Patent Application
20130282264
This invention relates to methods and systems for determining lane level speed information for road sections. More specifically, the invention relates to methods and systems for obtaining historical lane speed profiles for road sections. The invention also extends to methods and systems of using the lane speed information in a navigation system, including providing lane information and/or guidance to users of navigation apparatus. Illustrative embodiments of the invention relate to the use of lane speed information in a navigation system including portable navigation devices (so-called PNDs), in particular PNDs that include Global Positioning System (GPS) signal reception and processing functionality, and to systems and methods involving such devices. The invention is also applicable to the use of lane level speed information in a navigation system including a navigation apparatus which forms part of an integrated navigation system, e.g. an in-vehicle navigation system.
The present invention is directed to methods and systems of obtaining lane level speed information, and to navigation systems and methods which may use such information. The navigation system may comprise navigation apparatus of any suitable form as discussed above, and in more detail below. One illustrative embodiment of the apparatus is a portable navigation device. Portable navigation devices (PNDs) that include GPS (Global Positioning System) signal reception and processing functionality are well known and are widely employed as in-car or other vehicle navigation systems.
In general terms, a modern PNDs comprises a processor, memory (at least one of volatile and non-volatile, and commonly both), and map data stored within said memory. The processor and memory cooperate to provide an execution environment in which a software operating system may be established, and additionally it is commonplace for one or more additional software programs to be provided to enable the functionality of the PND to be controlled, and to provide various other functions.
Typically these devices further comprise one or more input interfaces that allow a user to interact with and control the device, and one or more output interfaces by means of which information may be relayed to the user. Illustrative examples of output interfaces include a visual display and a speaker for audible output. Illustrative examples of input interfaces include one or more physical buttons to control on/off operation or other features of the device (which buttons need not necessarily be on the device itself but could be on a steering wheel if the device is built into a vehicle), and a microphone for detecting user speech. In a particularly preferred arrangement the output interface display may be configured as a touch sensitive display (by means of a touch sensitive overlay or otherwise) to additionally provide an input interface by means of which a user can operate the device by touch.
Devices of this type will also often include one or more physical connector interfaces by means of which power and optionally data signals can be transmitted to and received from the device, and optionally one or more wireless transmitters/receivers to allow communication over cellular telecommunications and other signal and data networks, for example Wi-Fi, Wi-Max GSM and the like.
PND devices of this type also include a GPS antenna by means of which satellite-broadcast signals, including location data, can be received and subsequently processed to determine a current location of the device.
The PND device may also include electronic gyroscopes and accelerometers which produce signals that can be processed to determine the current angular and linear acceleration, and in turn, and in conjunction with location information derived from the GPS signal, velocity and relative displacement of the device and thus the vehicle in which it is mounted. Typically such features are most commonly provided in in-vehicle navigation systems, but may also be provided in PND devices if it is expedient to do so.
The utility of such PNDs is manifested primarily in their ability to determine a route between a first location (typically a start or current location) and a second location (typically a destination). These locations can be input by a user of the device, by any of a wide variety of different methods, for example by postcode, street name and house number, previously stored “well known” destinations (such as famous locations, municipal locations (such as sports grounds or swimming baths) or other points of interest), and favourite or recently visited destinations.
Typically, the PND is enabled by software for computing a “best” or “optimum” route between the start and destination address locations from the map data. A “best” or “optimum” route is determined on the basis of predetermined criteria and need not necessarily be the fastest or shortest route. The selection of the route along which to guide the driver can be very sophisticated, and the selected route may take into account existing, predicted and dynamically and/or wirelessly received traffic and road information, historical information about road speeds, and the driver's own preferences for the factors determining road choice (for example the driver may specify that the route should not include motorways or toll roads).
In addition, the device may continually monitor road and traffic conditions, and offer to or choose to change the route over which the remainder of the journey is to be made due to changed conditions. Real time traffic monitoring systems, based on various technologies (e.g. mobile phone data exchanges, fixed cameras, GPS fleet tracking) are being used to identify traffic delays and to feed the information into notification systems.
PNDs of this type may typically be mounted on the dashboard or windscreen of a vehicle, but may also be formed as part of an on-board computer of the vehicle radio or indeed as part of the control system of the vehicle itself. The navigation device may also be part of a hand-held system, such as a PDA (Portable Digital Assistant) a media player, a mobile phone or the like, and in these cases, the normal functionality of the hand-held system is extended by means of the installation of software on the device to perform both route calculation and navigation along a calculated route.
Route planning and navigation functionality may also be provided by a desktop or mobile computing resource running appropriate software. For example, the Royal Automobile Club (RAC) provides an on-line route planning and navigation facility at http://www.rac.co.uk, which facility allows a user to enter a start point and a destination whereupon the server to which the user's PC is connected calculates a route (aspects of which may be user specified), generates a map, and generates a set of exhaustive navigation instructions for guiding the user from the selected start point to the selected destination. The facility also provides for pseudo three-dimensional rendering of a calculated route, and route preview functionality which simulates a user travelling along the route and thereby provides the user with a preview of the calculated route.
In the context of a PND, once a route has been calculated, the user interacts with the navigation device to select the desired calculated route, optionally from a list of proposed routes. Optionally, the user may intervene in, or guide the route selection process, for example by specifying that certain routes, roads, locations or criteria are to be avoided or are mandatory for a particular journey. The route calculation aspect of the PND forms one primary function, and navigation along such a route is another primary function.
During navigation along a calculated route, it is usual for such PNDs to provide visual and/or audible instructions to guide the user along a chosen route to the end of that route, i.e. the desired destination. It is also usual for PNDs to display map information on-screen during the navigation, such information regularly being updated on-screen so that the map information displayed is representative of the current location of the device, and thus of the user or user's vehicle if the device is being used for in-vehicle navigation.
An icon displayed on-screen typically denotes the current device location, and is centred with the map information of current and surrounding roads in the vicinity of the current device location and other map features also being displayed. Additionally, navigation information may be displayed, optionally in a status bar above, below or to one side of the displayed map information, examples of navigation information include a distance to the next deviation from the current road required to be taken by the user, the nature of that deviation possibly being represented by a further icon suggestive of the particular type of deviation, for example a left or right turn. The navigation function also determines the content, duration and timing of audible instructions by means of which the user can be guided along the route. As can be appreciated a simple instruction such as “turn left in 100 m” requires significant processing and analysis. As previously mentioned, user interaction with the device may be by a touch screen, or additionally or alternately by steering column mounted remote control, by voice activation or by any other suitable method.
A further important function provided by the device is automatic route re-calculation in the event that: a user deviates from the previously calculated route during navigation (either by accident or intentionally); real-time traffic conditions dictate that an alternative route would be more expedient and the device is suitably enabled to recognize such conditions automatically, or if a user actively causes the device to perform route re-calculation for any reason.
It is also known to allow a route to be calculated with user defined criteria; for example, the user may prefer a scenic route to be calculated by the device, or may wish to avoid any roads on which traffic congestion is likely, expected or currently prevailing. The device software would then calculate various routes and weigh more favourably those that include along their route the highest number of points of interest (known as POIs) tagged as being for example of scenic beauty, or, using stored information indicative of prevailing traffic conditions on particular roads, order the calculated routes in terms of a level of likely congestion or delay on account thereof. Other POI-based and traffic information-based route calculation and navigation criteria are also possible.
Although the route calculation and navigation functions are fundamental to the overall utility of PNDs, it is possible to use the device purely for information display, or “free-driving”, in which only map information relevant to the current device location is displayed, and in which no route has been calculated and no navigation is currently being performed by the device. Such a mode of operation is often applicable when the user already knows the route along which it is desired to travel and does not require navigation assistance.
Devices of the type described above, for example the GO950 LIVE model manufactured and supplied by TomTom International B.V., provide a reliable means for enabling users to navigate from one position to another.
While navigation systems are of great utility in providing route guidance, and traffic information, the Applicant has identified that further improvements in relation to obtaining speed information, i.e. traffic speed information for road sections, and providing guidance on the basis of such information would be desirable. In particular, the Applicant has realised that it would be desirable to be able to obtain traffic speed information at a lane level, and to provide guidance to users of navigation apparatus using such information.
Navigation systems may provide information regarding the number of lanes present in a given road section, particularly in the region of an interchange, and may provide guidance to the user as to which is the appropriate lane for a given destination. However, the information provided is limited to information regarding the appropriate exit lane for a given destination. The Applicant has realised that drivers often make lane changes other than when required to follow a particular route e.g. to follow a particular exit or entry. For example, a driver may feel that another lane is moving faster in a region of congested traffic, prompting them to change lane. It is known that it is undesirable for overall traffic flow for drivers to repeatedly change lane, and such behaviour may increase the risk of dangerous situations developing, and increase the stress level of drivers. A driver may switch to an apparently faster moving lane only to find shortly that the lane is moving slower than other lanes e.g. because there are many trucks in it. When negotiating an interchange, the driver may not know the best lane to use to reach the exit of the interchange, particularly when there is congestion.
The present invention is directed to the problem of obtaining lane level traffic speed information, and to methods of using such information in a navigation system.
In accordance with a first aspect of the invention there is provided a method comprising using vehicle probe data to determine a historical lane speed profile for each of a plurality of lanes of a multi-lane road section, the lanes having the same given direction of travel.
In accordance with a second aspect of the present invention there is provided a system comprising means for using vehicle probe data to determine a historical lane speed profile for each of a plurality of lanes of a multi-lane road section, the lanes having the same given direction of travel.
The present invention therefore involves the use of vehicle probe data to obtain historical speed profiles for same direction lanes of a multi lane road section. The historical speed profiles are lane level speed profiles. Thus a specific speed profile is determined for each individual lane of the plurality of lanes. As used herein, a “lane” refers to one of the strips into which the carriageway of the road is demarcated in a given direction. A lane is a part of a carriageway which is intended to be used by a single line of vehicles. The lanes for which historical speed profiles are determined in accordance with the invention are same direction lanes, i.e. lanes belonging to the same carriageway of the road section.
It has been found that vehicle probe data may be advantageously used in this context, as it may provide the ability to determine vehicle speeds to a high level of definition enabling accurate and useful lane level information to be obtained.
Any references to “probe data” herein refer to vehicle probe data unless the context demands otherwise. As used herein, the term “vehicle probe data” takes on its customary meaning in the art. Vehicle probe data refers to data obtained from probe devices associated with individual vehicles. Thus the individual vehicles act as traffic sensors. A probe device is a device that is capable of determining its position at different times, and providing information about its position at different times to a central controller. For example, the probe device may upload its position with a timestamp to the central controller for different times. In this way the central controller is provided with position data for the probe device at different times which may be used to obtain a “trace” of the path taken by the device. In embodiments a central controller therefore collects individual position traces for each of a plurality of probe devices associated with probe vehicles. The position data is typically GPS position data for the device. For example, in some systems, the position of the probe device may be uploaded to a central controller every 5 seconds with a timestamp.
In accordance with the invention the probe data includes data enabling a vehicle speed to be determined. The data may include speed data, or data which may be used to derive speed data, i.e. position data, such as GPS or GSM position data, and time data. Such data may be obtained from any type of probe device associated with a vehicle, e.g. from vehicles provided with a specific position sensor, from a stand alone or in built navigation apparatus located in the vehicle, or from mobile communication devices located in the vehicle e.g. a mobile phone of an occupant of the vehicle which can act as a position sensor, or using any other permanent or temporary vehicle based apparatus that may act as a sensor providing data which may be used directly or indirectly to obtain a vehicle speed.
In preferred embodiments the probe data comprises time and position data obtained from probe devices. The time and position data may be in the form of a probe trace for a probe device. The data is preferably received by a central controller. A probe device may provide the position and time information to a central controller in any manner. The device may automatically and periodically determine position and time information and upload the position and time information to the central controller. For example, position information may be uploaded with a time stamp for different times. In these arrangements, the device may upload the information in real-time, i.e. periodically provide position information to the central controller for a current time e.g. via a wireless communications means, or may store the information locally and upload it to the remote central controller at intervals, or upon request of the central controller, upon user intervention etc. In some arrangements the probe device could store position information and upload the position information to a central controller only when suitably connected thereto e.g. when connected to a computer, or when the vehicle is at a charging location etc. Uploading may occur automatically or only on intervention of a user. In these arrangements the data may be uploaded at different times with a time stamp. This will enable a probe trace to be determined by a central controller. In embodiments, the system therefore comprises a central controller.
A “lane speed profile” as used herein refers to a profile for the speed of flow of traffic in a direction along the lane for the road section. Thus the lane speed profile is a lane traffic speed profile. The lane speed profile is a profile relating to the longitudinal speed of traffic along the lane. The lane speed profile is historical, in that it does not reflect real-time traffic speeds in the lane, but is based upon probe data relating to past traffic flows. It will be appreciated that each historical lane speed profile will relate to a length of the lane over at least a part of the road section or the entire length of the road section. Thus the typical speed of traffic flow along the lane may vary over the length of the lane considered, such that the speed profile may reflect a varying typical speed over the length of the lane to which the profile relates e.g. depending upon the existence of exits, entries etc affecting the lane. The lanes for which the historical lane speed profiles are determined are preferably at least partially coextensive along their length.
If not explicitly stated herein, the system of the invention may comprise means for carrying out any of the method steps described, and the method may comprise carrying out any of the steps the system is stated to be arranged to perform. The means for may be a set of one or more processors for carrying out the step mentioned.
In accordance with the invention, the method comprises processing vehicle probe data to determine the historical lane speed profiles, and the system comprises means for so doing e.g. a set of one or more processors.
Preferably the step of using the vehicle probe data to determine the historical lane speed profiles is carried out by a central controller, and the system comprises a central controller arranged to carry out the steps of the method described for determining lane speed profiles.
In embodiments the method further comprises obtaining the vehicle probe data for processing to determine the historical lane speed profiles, and preferably comprises collecting the vehicle probe data. The system may then comprise means for so doing. However, the vehicle probe data may be obtained in any manner. For example, the data may be data which has been collected and stored for another purpose, and the method of the invention may then involve processing already collected data. The method may comprise collecting the vehicle probe data at a central controller for processing in order to determine the historical lane speed profiles, and the system may comprise a central controller for collecting the data for processing. The probe data may be transmitted from individual vehicles for collection e.g. to a central controller. The data may be transmitted directly or indirectly to the central controller. For example, the data may be collected at a regional controller and forwarded to a central controller for processing with data from other regional controllers. In some embodiments therefore, the step of using the vehicle probe data to obtain the historical lane speed profiles is carried out by a central controller e.g. a set of one or more processors thereof. However, equally it is envisaged that the data could be collected and/or processed to determine lane speed profiles in other manners, e.g. by individual local navigation apparatus, or navigation devices having suitable processing power, or by a combination of a central controller and other apparatus e.g. local navigation apparatus.
The method may further comprise storing the vehicle probe data to be used in determining the historical lane speed profiles. The vehicle probe data may be stored locally or remote to a processor which determines the lane speed profiles. It will be appreciated that processing and/or storage of data may occur in multiple locations. The data may be stored by the central controller.
In embodiments the method comprises using probe vehicle data relating to the movement of each of a plurality of individual vehicles along each lane to obtain the historical lane speed profile for the lane, and the system comprises means for so doing. The vehicle probe data used to determine each historical lane speed profile comprises data which may be used to determine an overall traffic speed for the given lane. The data relates to the movement of a plurality of individual vehicles along the given lane. Thus the data may be lane level longitudinal speed data for individual vehicles or enables such data to be determined. The vehicle probe data may comprise speed data for each of a plurality of individual vehicles travelling along each lane, or data enabling speed data for each of a plurality of individual vehicles travelling along each lane to be determined. The data therefore enables speed data for individual vehicles to be directly or indirectly determined. For example, the probe data may comprise speed data, or may comprise data relating to the position of each individual vehicle with respect to time. Probe points and associated times may be used to determine a speed of travel of a probe vehicle. In some embodiments the vehicle probe data comprises probe traces for the position of individual vehicles travelling along each lane for which a historical lane speed profile is determined with respect to time i.e. longitudinal vehicle probe traces.
It will be appreciated that only probe data determined to relate to vehicles in a given lane is used to determine the historical lane speed profile for the lane. Thus each historical lane speed profile is determined using probe data relating to vehicle speeds for the lane. The probe data used to determine a historical speed profile for a given lane is thus probe data relating to a single lane.
Historical lane speed profiles may be derived using techniques similar to those used to determine historical speed profiles at a road level i.e. non lane level speed profiles. For example, some methods are described in the Applicant's co-pending WO 2009/053405A1, entitled “Method and Machine for Generating Map Data and Method and Navigation Device for Determining a Route using Map Data.”
It will be appreciated that the techniques of the invention may require knowledge of the lane structure of the road section in at least the direction of travel of the plurality of lanes along the length of the road section. The lane structure information may include the number of lanes in the road section and/or a lane width for each lane. Lane structure information may be obtained in any manner. For example, existing lane level map data may be used. Lane level digital map data is already used to provide guidance to road users regarding lane selection to reach a particular destination.
The step of determining the historical lane speed profiles may comprise determining to which lane vehicle probe data for the road section relates, and the system may comprise means for so doing. This may enable the data to be used to calculate a lane speed profile. The method may comprise assigning vehicle probe data to each lane for which a historical lane speed profile is to be determined. For example, in embodiments, vehicle probe information may be collected which relates to all vehicles travelling along the road section in one or both directions. In order to determine a historical speed profile for a plurality of lanes of the road section in the given direction it may first be necessary to determine which data relates to vehicles in the lane of interest.
This may be done using lane structure information for the road section i.e. information regarding the position of the lanes in the road section. Data describing the lane structure of road sections is readily available, and it has been found that probe vehicle data may describe the position of vehicles to a degree of accuracy which enables it to be determined in which lane a vehicle is travelling by matching vehicle positions to the lanes. Alternatively, vehicle probe data may itself be used to determine lane structure information by consideration of a distribution of probe traces across a width of the road section.
In accordance with the invention in any of its embodiments, the method may further comprise aggregating data relating to the speeds of each of a plurality of individual vehicles along a lane to obtain the historical lane speed profile for the lane, and the system comprises means for carrying out such a step. The speed data may be probe data or data derived using probe data. The data may be averaged in any manner.
In embodiments, individual vehicle probe traces may be processed together, e.g. by determining clusters of traces that relate to the same lane. The term “cluster” refers to the assignment of a population of observations into subsets, each subset being similar in one or more respects. For example, in this context, the clusters of traces share spatial similarities, e.g. a spatial correlation of observations or a grouping of observations having a minimum density. In some embodiments the method therefore comprises determining clusters of vehicle probe traces that relate to vehicles in the same lane, and using the cluster of vehicle probe traces in determining a historical lane speed profile for the lane. The clustering may be by reference to the speeds of probe vehicles and/or a position across the width of a road.
The historical lane speed profile for a lane may provide a profile for the typical speed of travel of traffic along the lane. Lane speed will typically be dependent upon time, in particular time of day. In preferred embodiments, the determined historical speed profile for each lane is specific to a given time. This may be achieved by using vehicle probe data relating to vehicles travelling along the lane at the given time to determine the historical lane speed profile. The given time may be a specific time or a range of time i.e. a time period. Preferably the given time is a time of day. It will be appreciated that lane speed profiles may alternatively or additionally be obtained that are specific to other times e.g. time of week, time of month, part of day, day of the week, week of the year, season, hour range, day range, minute range, particular hour etc. An average speed profile for a lane for a specified time range of interest may be obtained by aggregating individual vehicle speed data for the lane over the time range.
In embodiments the speed profile for each given lane is thus an average speed profile with respect to the speeds of each of a plurality of individual vehicles travelling along the lane and/or with respect to time.
In embodiments a plurality of historical lane speed profiles are determined for each lane being specific to a plurality of different given times, preferably times of day. For example, historical lane speed profiles may be determined for different given times at a given interval throughout the day, or at least in a part of the day.
In embodiments the method comprises determining historical lane speed profiles for each lane of the road section in the given direction of travel, and the system comprises means for carrying out such a step. In embodiments the method may comprise determining historical lane speed profiles for a plurality of lanes of the road section in the same direction for each direction of travel, and preferably for each lane in each direction of travel, and the system comprises means for so doing.
The historical lane speed profile for each one of the plurality of lanes, and any additional lanes may be obtained in the manner described in relation to any of the embodiments for obtaining a historical lane speed profile above. Thus the above techniques are applicable to determining a or each lane speed profile. Of course, different historical lane speed profiles may be obtained in different manners.
The method may further comprise identifying a road section for which to determine the historical lane speed profiles, and the system may comprise means for so doing. The method may then further comprise selecting vehicle probe data relating to the road section for use in determining the historical lane speed profiles.
The road section may be any part of a road which includes multiple lanes in at least one direction of travel. The road section could be the entire length of a road, or a part of the length thereof. For example, the road section could be a section between first and second interchanges or intersections. The road section may include multiple lanes along the entire length thereof or only a part, and may comprise multiple lanes in one or both directions of travel. In some embodiments the road section is a section of a road having at least two lanes in one or both directions along the length thereof, and preferably at least three. Such roads may be motorways. Lane structure information is particularly readily available for such roads. However, it will be appreciated that the section may be a section of a road which does not have multiple lanes other than in the section or sections concerned. In some embodiments the road section is a road section in the region of an interchange.
While the invention could be used to determine historical lane speed profiles for lanes over the entire lengths of roads, it is particularly applicable to determining historical lane speed profiles for specific road sections, for example where congestion is known to be problematic, where the lane arrangement is complex, in the vicinity of interchanges, exits, etc. The road section may be a section which is only temporarily problematic e.g. being a road section in the region of road works. The road section may fall within these criteria at all times, or only at a time to which the lane speed profile relates. Applying the techniques of the invention to specific road sections may provide a balance between determining useful lane level information which may provide benefits when applied in the manners discussed below, and conserving processing power. The road section or sections may be selected as being road sections where it would be desirable for a navigation apparatus to be able to provide lane information to a user.
In some embodiments, the road section for which the historical lane speed profiles are determined is a road section which may be considered regularly congested at least at a time to which the historical lane speed profiles relate. Any definition of a congested road section may be used. In some embodiments, the road section is a road section along which traffic flow speed has been found to regularly be less than a given threshold value of a maximum theoretical speed for the road section at least for a time period to which the historical lane speed profile relates. For example, the threshold value might be 50% of the maximum theoretical speed for the road section at a given time. The level of congestion of a road section may be assessed using any type of traffic flow information for the road as a whole, or at least a given direction of travel. This traffic flow information need not be lane level information.
In some embodiments the road section is one or more of; a section of a road which has at least three lanes in each direction of travel, or a road section in the vicinity of or including one or more of; roadworks, a frequent accident hot spot, an exit or entry to a road, an interchange or intersection, a merger with a lane from another road, a splitting of a road, or a frequently congested section of road. Such possibilities are merely exemplary, and the methods of the present invention may be applied to any desired road section, for which it is deemed useful to determine historical lane speed profiles for any reason. The road section need not be a road section including a section of only a single road. The road section may include sections of more than one road, for example, including parts of roads meeting at an interchange etc. It is believed that the methods of the present invention may be applicable on a dynamic basis to determine historical lane speed profiles for lanes of road sections which are of interest at a given time. For example, it is envisaged that a navigation apparatus could request that a historical lane speed profile be derived for a particular road section where problems have been encountered, or even derive such a profile itself.
The method may further comprise storing each historical lane speed profile. The method may comprise storing the speed profile in association with information identifying the lane to which the data relates, and optionally a given time to which the profile relates. The method may further comprise storing each lane speed profile in association with information identifying the road section to which the speed profile relates. The system may comprise means for storing such data. The method may creating a database of historical lane speed profiles. The lane speed profiles may be stored by the central controller.
It will be appreciated that the above steps may be repeated for multiple road sections to enable a database of road sections and associated historical lane speed profiles to be built up. Multiple historical lane speed profiles may be associated with each road section e.g. for different times of day etc. Thus, in some embodiments the method may comprise using the vehicle probe data to determine historical lane speed profiles for each of a plurality of individual lanes of a plurality of multi-lane road sections, wherein the plurality of individual lanes are lanes for the same given direction of travel, and may comprise storing historical lane speed profiles for each of a plurality of individual lanes of each of a plurality of multi-lane road sections.
The historical lane speed profiles may be used in any suitable manner.
The plurality of individual lanes of the road section for which historical speed profiles are determined are different lanes. It has been found that it may be useful to use historical lane speed profiles relating to two different lanes of the plurality of lanes to determine a historical lane speed difference profile between the two lanes. In some embodiments the method further comprises using the historical lane speed profiles determined for two of the plurality of lanes to determine a historical speed difference profile between the lanes, and the system comprises means for so doing. Preferably the two lanes are adjacent lanes. Such a profile may provide an indication as to which of the lanes is typically faster or slower. The steps may be repeated for any pair of lanes of the plurality of lanes where the plurality of lanes for which historical lane speed profiles are determined comprise more than two lanes. If the historical lane speed profiles for each lane are specific to a given time, the speed difference profile will relate to the typical speed difference between the lanes at the given time e.g. time of day. Relative speed information may be useful in determining lane guidance as discussed below. The relative speed information may be determined by a central controller.
The method preferably further comprises using the historical lane speed profiles in a navigation method or system. In embodiments the method further comprises using the historical lane speed profiles to provide lane guidance or information to a user of a navigation apparatus. In some preferred embodiments the method comprises providing lane information or guidance to the user via the navigation apparatus. The system may further comprise means for providing lane information or guidance using the historical lane speed profiles to a user via a navigation apparatus. The system may comprise the navigation apparatus.
Lane guidance or information may be determined by individual navigation apparatus using the historical lane speed profiles. It will be appreciated that a navigation apparatus may comprise a set of one or more processors which determine the lane information or guidance. The navigation apparatus may determine the historical lane speed profiles if a central controller does not carry out this step. However, in other embodiments, the method comprises the step of providing the lane information to the navigation apparatus e.g. transmitting the information to the navigation apparatus. The information may be transmitted from a central controller. Preferably the user is a user travelling through the road section. In yet other embodiments, lane guidance or information may be determined by a combination of a central controller and a navigation apparatus.
The lane information or guidance may be provided to a user of a navigation apparatus at any stage. In preferred embodiments the lane information or guidance is provided when the user is travelling through the road section or is about to enter the road section. In embodiments, the navigation apparatus is a mobile apparatus. Preferably the apparatus is located in a vehicle. The current location of the navigation apparatus corresponds to that of the user (or vehicle). The method may therefore further comprise detecting when a current position e.g. a GPS position (of the user or navigation apparatus) is within the road section or about to enter the road section. Preferably the lane information or guidance is automatically provided to the user via the apparatus e.g. when the current position is within or about to enter the road section. However, it is envisaged that the information could be provided at any stage, e.g. in response to a user input, such as when planning a route, even if the user/navigation apparatus is not in the vicinity of the road section.
In some embodiments the lane information may be information regarding the expected speeds of travel along different lanes of the road section based on the historical lane speed profiles. The method may comprise displaying information regarding the expected speeds of travel along the different lanes of the road section. This may be in the form of information regarding absolute lane speeds or relative speeds between the lanes. The method may comprise displaying the information on a display of the navigation apparatus. In some embodiments the method may comprise using the information to enhance a displayed digital map. The information may, for example, be superimposed on a display of the lane structure of the road section. The user may then make their own decision as to whether to change lanes. For example, the user may be in slow moving traffic in the vicinity of an interchange. The displayed lane speed information may reassure the user that their current lane is likely to be the fastest once the interchange has been passed. Simply providing information to the user regarding the likely traffic flow speeds in each lane may help to reduce driver stress, and reduce the number of unnecessary lane manoeuvres performed, providing the potential to improve overall traffic flow. In these embodiments, the lane information preferably includes lane information at least for the region which lies ahead of the current position of the user.
In preferred embodiments the method comprises providing lane guidance. The lane guidance is preferably provided via a navigation apparatus. In some embodiments the guidance is guidance to a user regarding the selection of a lane or lanes in the road section. For example, this may be guidance regarding a lane selection when following a route through at least a part of the road section. The route may pass through the entire road section or a part thereof. For example, the route may pass through the first part of the road section before following an exit at an interchange included in the road section to reach a different road. The lane selection may comprise a lane recommendation for the user on the basis of the historical lane speed profiles. The lane guidance may be in accordance with predefined or user specified criteria. For example, the user may always wish to be notified of the lane with historically quickest speeds in a given road section, or may instead wish to travel in a slower lane, or a lane with typical speeds less than a given speed, e.g. if they drive a particular type of vehicle.
The lane guidance may comprise a lane selection which has been determined to provide the quickest expected route through at least a part of the road section, on the basis of the historical lane speed profiles. In some preferred embodiments the method therefore further comprises using the historical lane speed profiles to determine a lane selection providing the quickest expected route through at least a part of the road section. For example, a user may wish to travel from a first location to a second location along a route involving the multi-lane road section. Sometimes it may not be apparent to the user which lane to select. While the “inside” lane i.e. that closest to the centre of the carriageway may be intended to be the fastest lane, this may not always be the case, e.g. in the proximity of an exit, if the lane is used heavily by trucks etc. The present invention may set a user's mind at rest, providing them with the optimum lane selection for a route through a road section based on the historical lane speed profiles with respect to speed or any other specified criteria. In some embodiments the lane selection is a lane selection determined to result in the quickest expected route through only the road section or part thereof, while in other embodiments it may be a lane selection determined to result in a quickest expected route through the road section or part thereof as part of a route including the road section, i.e. which may extend to a destination beyond the road section.
In some preferred embodiments the lane guidance comprises a lane selection which is determined to provide the quickest expected route through the road section while minimizing the number of lane changes. The method may then comprise using the historical lane speed profiles to determine a lane selection providing the quickest expected route through at least a part of the road section while minimizing the number of lane changes. Such embodiments are useful in improving overall traffic flow by reducing the number of lane changes performed by drivers, which are known to have a negative impact on traffic flow.
In accordance with other embodiments, the road section may comprise a road interchange or intersection, and the lane guidance may be a lane selection including the lane expected to have the highest speed at the entrance to the interchange or intersection and the lane expected to have the highest speed at the exit of the interchange or intersection on the basis of the historical lane speed profiles. The method may comprise determining a lane selection for a route through the road section from a lane having the highest expected speed at the entrance to the interchange or intersection to the lane having the highest expected speed at the exit of the interchange or intersection on the basis of the historical lane speed profiles. The lane guidance may provide such a route. The route may be a quickest route. The route through the interchange may not necessarily be the quickest route, but may be a route which most efficiently navigates from the quickest entry lane to the quickest exit lane. For example, this may be done in a manner to minimise lane changes. The lanes having the highest expected speeds at the entrance and the exit of the interchange or intersection are preferably lanes on a route along which the user is being guided i.e. a route calculated by the navigation apparatus.
In accordance with any of the embodiments of the invention, the step of providing lane guidance may comprise providing at least one instruction regarding a lane selection to a user via the navigation apparatus. The or each instruction may be an instruction regarding a lane change or an instruction to maintain lane. The lane guidance may comprise a sequence of lane selection instructions. The lane change could be a change to a lane leading ultimately to a different destination e.g. an exit lane or to a different speed lane leading to the same destination. For example, the guidance may instruct a user to stay in their current lane rather than changing to an apparently faster moving lane, as the faster moving lane is expected to become the slower lane after the next interchange. It will be appreciated that one or more instructions may be provided. Thus the lane selection referred to herein may be a lane selection for a route through the road section, with the user being provided with a sequence of lane selection instructions along the route. In other embodiments, a lane selection for an entire route through the road section may be provided in a single instruction e.g. using a visual display of an interchange etc. The lane selection may be imparted to the user in a similar manner to the way in which instructions regarding a calculated route are given.
The lane selection instruction or instructions may be of any form. For example, the lane selection instruction may be audible and/or visual. The lane selection instruction may be provided in the same manner as any other navigation instruction provided by a navigation apparatus. A lane selection instruction could be provided by an enhancement to a displayed map.
Alternatively or additionally, in some embodiments the method may further comprise using the historical lane speed profiles to determine a timing for providing a lane selection instruction to a user of a navigation apparatus. In these embodiments the lane selection instruction may or may not be a lane selection instruction determined using the historical lane speed profiles. For example, the lane selection instruction may be dictated by a route that the user is following. In these embodiments the route calculation is preferably performed by a navigation apparatus. In some embodiments the timing is a timing which is determined to result in the quickest travel through the road section.
In some embodiments the method may further comprise calculating a route between a first location and a second location along which a user of a navigation apparatus is to be guided, the route including at least a part of the road section, wherein the method comprises using the historical lane speed profiles to determine a timing for providing a lane selection instruction to the user via the navigation apparatus required for the user to follow the route. In other embodiments the method may comprise determining a lane selection to provide a quickest route through at least a part of the road section, and using the lane speed historical profiles to determine a timing for providing an instruction to the user to enable the user to follow the lane selection.
In these embodiments in which the historical lane speed profiles are used to determine a timing for providing a lane selection instruction to the user of the navigation apparatus, it may be determined, for example, that although the user needs to move to a right hand lane in order to be able to continue straight ahead after an interchange, it is better not to do this immediately a direction indication suggests that a lane change will be needed, but instead to wait until after traffic in the right hand lane has left the road at an exit which results in a relatively lower lane speed for the right hand lane up to the exit.
Another example might be that historical lane speed profiles suggest that the lane speed in a current lane is likely to be low up to and including the point where a lane change is required, e.g. a lane change to an exit lane. The timing may then be a timing intended to increase the time available for the user to perform the lane change. This may increase ease of negotiation of the road section.
The methods of the present invention may provide the ability to more accurately estimate durations for calculated routes. The method may further comprise using the historical lane speed profiles to determine an estimated duration for a calculated route including at least a part of the road section. It will be appreciated that it may be known which lane a user must follow in at least parts of the road section to follow a particular route, or due to certain lane prohibitions which might mean that the user has to travel in certain lanes. The duration may be communicated to a user via the navigation apparatus.
The historical lane speed profiles may also be used to provide an alert, message or warning to a user of a navigation apparatus following a route including at least a part of the road section. The alert, message or warning may be provided via the navigation apparatus. For example the user could be warned of expect heavy traffic in a particular lane, of high levels of traffic merging from one side etc.
References to an interchange herein refer to any form of interchange. For example the interchange may include one or more of an intersection or roundabout.
It will be appreciated that other information may be used in addition to the historical lane speed profiles to provide lane information or guidance to users of a navigation apparatus. For example, any or all of real-time traffic flow information, information regarding lane usage restrictions for the road section, information regarding lane manoeuvre restrictions for the road section etc. may be additionally used. For example, in some road sections it may not be possible to change back to an first lane after moving into a second lane from the first lane e.g. when the second lane is an exit lane. In other arrangements, certain lanes may be specifically designated for certain types of vehicle. Any form of lane guidance or information may be provided to the user via the navigation apparatus.
In accordance with the invention, the historical lane speed profiles are preferably determined by a central controller. In accordance with a further aspect of the invention, the present invention provides a central controller comprising means for using vehicle probe data to determine a historical lane speed profile for each of a plurality of lanes of a multi-lane road section, the plurality of lanes each having the same given direction of travel. The central controller may comprise means for carrying out any of the steps of the invention in accordance with the embodiments described. The steps of using the lane speed profiles may be carried out by a navigation apparatus and/or a central controller. For example, lane guidance information or instructions, timing information, route duration, warnings, alerts, messages etc may be determined using the profiles by the central controller, a navigation apparatus, or a combination thereof. The lane guidance information or instructions, timing information, alerts, messages, route duration etc are preferably communicated to a user via a navigation apparatus.
Any or all of the steps said to be carried out by a central controller may all be carried out by the same central controller.
It will be appreciated that any of the further aspects of the invention may include any or all of the features of the invention described in relation to any other aspects and embodiments of the invention to the extent they are not mutually inconsistent therewith.
The principles of the present invention are applicable to any form of navigation apparatus. In accordance with any of the aspects or embodiments of the invention the apparatus may comprise a display for displaying a digital map to a user, a processor configured to access digital map data and cause a digital map to be displayed to a user via the display, and a user interface operable by a user to enable the user to interact with the apparatus.
References to a processor may refer to a set of one or more processors. References to a system, apparatus or central controller comprising “means for” carrying out a step in accordance with any of the aspects or embodiments of the invention described herein may be replaced by a reference to a set of one or more processors for carrying out the step. Thus the means for carrying out any of the steps described herein may be a set of one or more processors.
One particular area of utility is in relation to portable navigation devices (PND). In embodiments, therefore, the navigation apparatus is an apparatus of a portable navigation device (PND). In accordance with a further aspect, the navigation apparatus referred to in the aspects and embodiments of the invention above is a portable navigation device (PND).
The invention is also applicable to navigation apparatus which is provided as part of an integrated navigation system. For example the apparatus may form part of an in-vehicle integrated navigation system. In accordance with another aspect of the invention, the navigation apparatus described herein may form part of a navigation system. The navigation system may be an integrated in-vehicle navigation system.
Regardless of its implementation, a navigation apparatus used in accordance with the present invention may comprise a processor, memory, and digital map data stored within said memory. The processor and memory cooperate to provide an execution environment in which a software operating system may be established. One or more additional software programs may be provided to enable the functionality of the apparatus to be controlled, and to provide various other functions. A navigation apparatus of the invention may preferably include GPS (Global Positioning System) signal reception and processing functionality. The apparatus may comprise one or more output interfaces by means of which information may be relayed to the user. The output interface(s) may include a speaker for audible output in addition to the visual display. The apparatus may comprise input interfaces including one or more physical buttons to control on/off operation or other features of the apparatus.
In other embodiments, the navigation apparatus may be implemented by means of an application of a processing device which does not form part of a specific navigation device. For example the invention may be implemented using a suitable computer system arranged to execute navigation software. The system may be a mobile or portable computer system e.g. a mobile telephone or laptop, or may be a desktop system.
The present invention extends to a computer program product comprising computer readable instructions executable to perform a method according to any of the aspects or embodiments of the invention, or to cause a navigation apparatus or central controller to perform such methods.
Advantages of these embodiments are set out hereafter, and further details and features of each of these embodiments are defined in the accompanying dependent claims and elsewhere in the following detailed description.
Various aspects of the teachings of the present invention, and arrangements embodying those teachings, will hereafter be described by way of illustrative example with reference to the accompanying drawings, in which:
Some preferred embodiments of the invention will now be described by way of example only, and with reference to
Preferred embodiments of the present invention will now be described with particular reference to a PND. It should be remembered, however, that the teachings of the present invention are not limited to PNDs but are instead universally applicable to any type of processing device that is configured to execute navigation software so as to provide route planning and navigation functionality. It follows therefore that in the context of the present application, a navigation device is intended to include (without limitation) any type of route planning and navigation device, irrespective of whether that device is embodied as a PND, a navigation device built into a vehicle, or indeed a computing resource (such as a desktop or portable personal computer (PC), mobile telephone or portable digital assistant (PDA)) executing route planning and navigation software.
It will also be apparent from the following that the teachings of the present invention even have utility in circumstances where a user is not seeking instructions on how to navigate from one point to another, but merely wishes to be provided with a view of a given location. In such circumstances the “destination” location selected by the user need not have a corresponding start location from which the user wishes to start navigating, and as a consequence references herein to the “destination” location or indeed to a “destination” view should not be interpreted to mean that the generation of a route is essential, that travelling to the “destination” must occur, or indeed that the presence of a destination requires the designation of a corresponding start location.
With the above provisos in mind,
The GPS system is implemented when a device, specially equipped to receive GPS data, begins scanning radio frequencies for GPS satellite signals. Upon receiving a radio signal from a GPS satellite, the device determines the precise location of that satellite via one of a plurality of different conventional methods. The device will continue scanning, in most instances, for signals until it has acquired at least three different satellite signals (noting that position is not normally, but can be determined, with only two signals using other triangulation techniques). Implementing geometric triangulation, the receiver utilizes the three known positions to determine its own two-dimensional position relative to the satellites. This can be done in a known manner. Additionally, acquiring a fourth satellite signal will allow the receiving device to calculate its three dimensional position by the same geometrical calculation in a known manner. The position and velocity data can be updated in real time on a continuous basis by an unlimited number of users.
As shown in
The spread spectrum signals 160, continuously transmitted from each satellite 120, utilize a highly accurate frequency standard accomplished with an extremely accurate atomic clock. Each satellite 120, as part of its data signal transmission 160, transmits a data stream indicative of that particular satellite 120. It is appreciated by those skilled in the relevant art that the GPS receiver device 140 generally acquires spread spectrum GPS satellite signals 160 from at least three satellites 120 for the GPS receiver device 140 to calculate its two-dimensional position by triangulation. Acquisition of an additional signal, resulting in signals 160 from a total of four satellites 120, permits the GPS receiver device 140 to calculate its three-dimensional position in a known manner.
The navigation device 200 is located within a housing (not shown). The housing includes a processor 210 connected to an input device 220 and a display screen 240. The input device 220 can include a keyboard device, voice input device, touch panel and/or any other known input device utilised to input information; and the display screen 240 can include any type of display screen such as an LCD display, for example. In a particularly preferred arrangement the input device 220 and display screen 240 are integrated into an integrated input and display device, including a touchpad or touchscreen input so that a user need only touch a portion of the display screen 240 to select one of a plurality of display choices or to activate one of a plurality of virtual buttons.
The navigation device may include an output device 260, for example an audible output device (e.g. a loudspeaker). As output device 260 can produce audible information for a user of the navigation device 200, it is should equally be understood that input device 240 can include a microphone and software for receiving input voice commands as well.
In the navigation device 200, processor 210 is operatively connected to and set to receive input information from input device 220 via a connection 225, and operatively connected to at least one of display screen 240 and output device 260, via output connections 245, to output information thereto. Further, the processor 210 is operably coupled to a memory resource 230 via connection 235 and is further adapted to receive/send information from/to input/output (I/O) ports 270 via connection 275, wherein the I/O port 270 is connectible to an I/O device 280 external to the navigation device 200. The memory resource 230 comprises, for example, a volatile memory, such as a Random Access Memory (RAM) and a non-volatile memory, for example a digital memory, such as a flash memory. The external I/O device 280 may include, but is not limited to an external listening device such as an earpiece for example. The connection to I/O device 280 can further be a wired or wireless connection to any other external device such as a car stereo unit for hands-free operation and/or for voice activated operation for example, for connection to an ear piece or head phones, and/or for connection to a mobile phone for example, wherein the mobile phone connection may be used to establish a data connection between the navigation device 200 and the internet or any other network for example, and/or to establish a connection to a server via the internet or some other network for example.
Further, it will be understood by one of ordinary skill in the art that the electronic components shown in
In addition, the portable or handheld navigation device 200 of
Referring now to
The establishing of the network connection between the mobile device (via a service provider) and another device such as the server 302, using an internet (such as the World Wide Web) for example, can be done in a known manner. This can include use of TCP/IP layered protocol for example. The mobile device can utilize any number of communication standards such as CDMA, GSM, WAN, etc.
As such, an internet connection may be utilised which is achieved via data connection, via a mobile phone or mobile phone technology within the navigation device 200 for example. For this connection, an internet connection between the server 302 and the navigation device 200 is established. This can be done, for example, through a mobile phone or other mobile device and a GPRS (General Packet Radio Service)-connection (GPRS connection is a high-speed data connection for mobile devices provided by telecom operators; GPRS is a method to connect to the internet).
The navigation device 200 can further complete a data connection with the mobile device, and eventually with the internet and server 302, via existing Bluetooth technology for example, in a known manner, wherein the data protocol can utilize any number of standards, such as the GPRS, the Data Protocol Standard for the GSM standard, for example.
The navigation device 200 may include its own mobile phone technology within the navigation device 200 itself (including an antenna for example, or optionally using the internal antenna of the navigation device 200). The mobile phone technology within the navigation device 200 can include internal components as specified above, and/or can include an insertable card (e.g. Subscriber Identity Module or SIM card), complete with necessary mobile phone technology and/or an antenna for example. As such, mobile phone technology within the navigation device 200 can similarly establish a network connection between the navigation device 200 and the server 302, via the internet for example, in a manner similar to that of any mobile device.
For GPRS phone settings, a Bluetooth enabled navigation device may be used to correctly work with the ever changing spectrum of mobile phone models, manufacturers, etc., model/manufacturer specific settings may be stored on the navigation device 200 for example. The data stored for this information can be updated.
In
The server 302 includes, in addition to other components which may not be illustrated, a processor 304 operatively connected to a memory 306 and further operatively connected, via a wired or wireless connection 314, to a mass data storage device 312. The processor 304 is further operatively connected to transmitter 308 and receiver 310, to transmit and send information to and from navigation device 200 via communications channel 318. The signals sent and received may include data, communication, and/or other propagated signals. The transmitter 308 and receiver 310 may be selected or designed according to the communications requirement and communication technology used in the communication design for the navigation system 200. Further, it should be noted that the functions of transmitter 308 and receiver 310 may be combined into a signal transceiver.
Server 302 is further connected to (or includes) a mass storage device 312, noting that the mass storage device 312 may be coupled to the server 302 via communication link 314. The mass storage device 312 contains a store of navigation data and map information, and can again be a separate device from the server 302 or can be incorporated into the server 302.
The navigation device 200 is adapted to communicate with the server 302 through communications channel 318, and includes processor, memory, etc. as previously described with regard to
Software stored in server memory 306 provides instructions for the processor 304 and allows the server 302 to provide services to the navigation device 200. One service provided by the server 302 involves processing requests from the navigation device 200 and transmitting navigation data from the mass data storage 312 to the navigation device 200. Another service provided by the server 302 includes processing the navigation data using various algorithms for a desired application and sending the results of these calculations to the navigation device 200.
The communication channel 318 generically represents the propagating medium or path that connects the navigation device 200 and the server 302. Both the server 302 and navigation device 200 include a transmitter for transmitting data through the communication channel and a receiver for receiving data that has been transmitted through the communication channel.
The communication channel 318 is not limited to a particular communication technology. Additionally, the communication channel 318 is not limited to a single communication technology; that is, the channel 318 may include several communication links that use a variety of technology. For example, the communication channel 318 can be adapted to provide a path for electrical, optical, and/or electromagnetic communications, etc. As such, the communication channel 318 includes, but is not limited to, one or a combination of the following: electric circuits, electrical conductors such as wires and coaxial cables, fibre optic cables, converters, radio-frequency (RF) waves, the atmosphere, empty space, etc. Furthermore, the communication channel 318 can include intermediate devices such as routers, repeaters, buffers, transmitters, and receivers, for example.
In one illustrative arrangement, the communication channel 318 includes telephone and computer networks. Furthermore, the communication channel 318 may be capable of accommodating wireless communication such as radio frequency, microwave frequency, infrared communication, etc. Additionally, the communication channel 318 can accommodate satellite communication.
The communication signals transmitted through the communication channel 318 include, but are not limited to, signals as may be required or desired for given communication technology. For example, the signals may be adapted to be used in cellular communication technology such as Time Division Multiple Access (TDMA), Frequency Division Multiple Access (FDMA), Code Division Multiple Access (CDMA), Global System for Mobile Communications (GSM), etc. Both digital and analogue signals can be transmitted through the communication channel 318. These signals may be modulated, encrypted and/or compressed signals as may be desirable for the communication technology.
The server 302 includes a remote server accessible by the navigation device 200 via a wireless channel. The server 302 may include a network server located on a local area network (LAN), wide area network (WAN), virtual private network (VPN), etc.
The server 302 may include a personal computer such as a desktop or laptop computer, and the communication channel 318 may be a cable connected between the personal computer and the navigation device 200. Alternatively, a personal computer may be connected between the navigation device 200 and the server 302 to establish an internet connection between the server 302 and the navigation device 200. Alternatively, a mobile telephone or other handheld device may establish a wireless connection to the internet, for connecting the navigation device 200 to the server 302 via the internet.
The navigation device 200 may be provided with information from the server 302 via information downloads which may be periodically updated automatically or upon a user connecting navigation device 200 to the server 302 and/or may be more dynamic upon a more constant or frequent connection being made between the server 302 and navigation device 200 via a wireless mobile connection device and TCP/IP connection for example. For many dynamic calculations, the processor 304 in the server 302 may be used to handle the bulk of the processing needs, however, processor 210 of navigation device 200 can also handle much processing and calculation, oftentimes independent of a connection to a server 302.
As indicated above in
The navigation device 200 may sit on an arm 292, which itself may be secured to a vehicle dashboard/window/etc. using a suction cup 294. This arm 292 is one example of a docking station to which the navigation device 200 can be docked.
As shown in
The present invention involves the creation of historic lane speed profiles for road sections using vehicle probe data. Some exemplary embodiments regarding the way in which such profiles may be determined using vehicle probe data will now be described, before exemplary uses of the historic lane speed profiles are described.
The method may first involve a step of identifying a road section for which historic lane speed profiles are to be derived. The road section is a road section with at least one carriageway having at least two lanes. By a carriageway, it is meant the part of the road for travel in a single direction. Thus a two-way road includes two carriageways, each of which may comprise one or more lanes. The selection of the road section may be carried out in any manner.
The techniques of the invention are particularly applicable to road sections which are often susceptible to congestion. One way of identifying such road sections may be to consider the traffic flow speeds on road sections compared to a maximum theoretical speed for the road section. For example, road sections may be selected which are found to have traffic flow speeds at or lower than 50% of a maximum theoretical speed for the road section on the basis of traffic data such as TomTom's HD Traffic™ data. This may be by reference to the level of congestion for the road section, or a carriageway thereof as a whole, rather than by consideration of lane level traffic speeds. Other definitions of a congested or semi-congested road can of course be used. Rather than considering road sections that are susceptible to congestion, road sections may alternatively or additionally be chosen as they include an interchange, intersection, complicated lane structure, one or more entries or exits, roadworks, accident hotspots, regions where a road merges or splits etc, or any road section where it may be advantageous to obtain lane level speed information to be able to provide enhanced guidance to users of navigation devices. Such road sections may be road section where there are often significant differences in speed profile between different lanes in the same direction.
The vehicle probe data for the selected road section is first collected. In some preferred embodiments of the invention, the data is collected at a central controller for processing at the central controller to obtain historical lane speed profiles. However, it is envisaged that data could be collected and/or processed at individual PND's in other embodiments. The location at which data is collected and/or processed is not significant.
Vehicle probe data may be obtained from any suitable source, such as using a GPS and/or GSM probe collection system. The Applicant's HD Traffic™ systems use vehicle probe data to provide accurate traffic flow information at a road level. In embodiments of the present invention, vehicle probe data is instead used to determine lane level traffic flow information. The core sources of probe data are cell phone operators in various countries as well as GPS probes from suitably connected vehicle based navigation apparatus, or commercial fleets with appropriate sensors.
Probe data relating to the movement of individual vehicles along lanes in the road section is collected. This may be in the form of individual vehicle probe traces per lane i.e. longitudinal traces representative of the position of vehicles with respect to time along the length of the lane. The probe data should have a resolution i.e. points per minute sufficient to enable accurate speed data for individual vehicles to be determined at a lane level of resolution. It has been found that use of probe data with probe points at least every second may be appropriate to allow vehicle speeds to be accurately determined.
The probe data for the road section is collected for a specific time of day. For example data may be collected over a time period of one minute on a particular day to obtain a particular historic lane speed profile. Additional sets of probe data for other time periods may then be obtained to build up a set of historic lane speed profiles for different times over an entire day, and for each day of the week.
Individual vehicle speeds obtained by consideration of individual vehicle probe traces are aggregated to obtain an average lane speed profile for the time period. The lane speed profile may be validated over time.
Lane speed profiles may be calculated using the probe data in a similar manner to the way in which road speed profiles are calculated, for example as described in the Applicant's WO 2009/053405A1. In an exemplary embodiment it is assumed that the vehicle speeds over the road section are constant over a period of one minute. Vehicle probe traces i.e. longitudinal traces formed by probe position data over time for individual vehicles, are collected over a 60 second time domain for the road section. Probe traces may be allocated to sub-groups having different speed categories on the basis of the vehicle speeds indicated by the probe traces. The sub-groups may be matched to different lanes, by consideration of the position of the traces with respect to the width of the road section. In this way a speed per lane value may be determined. This may be carried out along the length of a lane to obtain an overall lane speed profiles. In some embodiments a speed difference or a speed variance between different lanes may be determined.
It will be appreciated that in order to derive lane level speed profiles it is necessary to determine which probe data relates to which lane i.e. in which lane individual probe vehicles are travelling. There are various ways of doing this. With sufficient probe points densities with respect to time, a position accuracy for probe vehicles of up to 1 m can be obtained. GNSS constellations currently in development are expected to be able to provide even higher levels of positioning accuracy which will still further improve the precision with which probes can be matched to lanes. Thus with knowledge of the lane structure of a road section it is possible to determine to which lane a probe vehicle belongs. This may be done by reference to map data describing the lane structure of road sections i.e. the number of lanes and the width of the lanes in each carriageway.
Map data should be used which is accurate in terms of the number of lanes in a road section, as well as the lane width and the beginning and ending of the lanes. The invention is particularly applicable to motorway type roads where lane structure information to a high degree of accuracy is already known from a variety of sources. For example, PND devices may rely upon such data to provide instructions to a user as to which lane to select to follow a particular route, e.g. to ensure that they will ultimately end up in an exit lane at the next interchange. Advanced Driver Assistance Systems (ADAS) quality maps may provide such levels of accuracy for different road types.
Rather than relying upon map data to provide lane information, in alternative techniques, the vehicle probe data itself can provide information regarding the lane structure of a road section. This may enable lane speed profiles to be determined without reliance upon third party map data, for example. This may be done by reference to a distribution of probes across the width of the road.
A historic lane speed difference profile may also be determined for the speed difference between lanes.
Once calculated the historical lane speed profiles determined may be stored in a database, together with any historic lane speed difference profiles determined. The historical lane speed profiles may be stored in conjunction with a time of day to which the profile applies, and information identifying the lane to which it relates. It is envisaged that historical lane speed profiles may be determined for a range of different times of interest to ensure that there are speed profiles available from which a profile which may provide a reasonable match to the current conditions a user of a navigation apparatus may expect to encounter can be selected. Speed profiles may be stored by a central controller.
Currently speed profiles for roads as a whole, rather than lane level speed profiles may be determined for example, for 5 minute intervals on everyday of the week in the TomTom Traffic™ system. Similar numbers of historical lane speed profiles could be derived in accordance with the invention. Alternatively, historical lane speed profiles could only be derived for certain parts of the day where congestion is known to be more of a problem, and when detailed knowledge of traffic levels per lane may provide greater benefits.
Once the historical lane speed profiles have been obtained, a suitable algorithm may be run on the data to provide lane guidance or information to a user of a PND. Such an algorithm may be run by an individual PND, or at a central traffic centre e.g. by a central controller. Where the lane guidance or information is determined centrally, the instructions e.g. a lane recommendation, or timing for providing a lane selection instruction may be transmitted to an individual PND for conveying to a user.
In accordance with the invention, the historical lane speed profiles may be used in a number of ways to provide guidance or information to a user of a PND.
To illustrate the significant variation in speed profile which may occur between lanes of a road section we will now refer to
The direction of travel in this case is from the bottom to the top of the Figure as indicated schematically by the arrows. The arrows indicate paths through the lanes which may be taken by a vehicle wishing to travel along the R0 road before taking a left hand turn onto the A10/E40 road toward Ghent as shown.
This road section includes a number of features which may influence lane speed. Starting from the bottom of the Figure, and considering a direction of travel according to the arrows from the bottom to the top of the Figure, in region a) there are three lanes in the main road, the R0. In this region typical lane speeds might be 75 kilometers an hour, 50 kilometers and hour and 10 kilometers an hour respectively for the left, middle and right hand lanes. At section b), typical lane speeds are 60 kilometers an hour, 40 kilometers and hour and 10 kilometers an hour for the left, middle and right-hand lanes. At section C, there are five lanes having typical speeds of 60 kilometers an hour, 50 kilometers an hour, 20 kilometers an hour, 20 kilometers an hour and 10 kilometers an hour from the left-hand lane towards the right-hand lane.
In the region of point d), the road divides, and the section leading towards the left-hand turn onto the A10/E40 has only two lanes, with typical lane speeds of 60 kilometers an hour and 10 kilometers an hour for the left and right lanes. Moving on to point e), this section includes only one lane along the desired route, with a typical lane speed of 20 kilometers an hour. Once section f) is reached, lane speeds increase again towards 70 kilometers an hour. At section g), there once again are three lanes, having lane speeds 50 kilometers an hour, 30 kilometers and hour and 10 kilometers an hour from left to right. At point h) the carriageway decreases from three lanes to two lanes, again causing disturbance.
It will be seen that there are therefore some significant differences between the lane speeds over the road section shown in
While typical traffic flow data for carriageways as a whole would simply show that the entire road section was congested, the lane level analysis of
In this example, a driver is initially at point a). In order to take the left-hand turn onto the E40/A10 just after point g), the driver will need to be in a lane to the right hand side of the carriageway by around section c). Using the lane speed information provided by lane speed profiles, it is apparent that there is no point in the driver moving over to the right-hand lane too soon, for example by point b), as the right-hand lane is moving very slowly in this section. Instead a lane selection instruction may be provided to the driver to stay in the left hand lane until after point a), to move to the middle lane by section b), and then by section c) move over to the third lane from the left which may lead to the desired exit.
In this instance, it is determined that in order to provide the fastest route through the road section, it is appropriate to defer providing a lane manoeuvre instruction to a driver initially in the left hand lane to make the lane change needed to enable them to follow their route in order to reduce the amount of time spent travelling in the slow right-hand lane. The recommended lane selection is indicated by the solid left-hand set of arrows between sections a), b) and c) in
This illustration shows how detailed information regarding the lane speed profiles for the lanes of a road section may be used to provide recommendations to a driver via a PND of the most appropriate lane selection for example to provide a fastest route through the road section. This also illustrates that the lane speed information may be used to determine a timing for providing a lane selection instruction i.e. an instruction to change lanes, for example to maximise the speed of travel through the road section. The lane selection instruction may be an instruction to a user to make a lane change necessary to follow a particular route. For example this is the case in the
The illustration with respect to
It would normally be expected that the left-hand lane would be the fastest lane. This is the inside carriageway for travel on the right-hand side of the road. However, it may be seen that traffic flow speeds in the left-hand lane are in fact lower than those in the middle lane in the region before the left-hand exit. This is because on this particular road section, slow moving trucks tend to move over to the left-hand lane in preparation for taking the left-hand exit. Thus, for a driver wishing to take the main carriageway straight ahead, the fastest lane selection would be stay in the middle lane until just past the left-hand exit, before moving to the left-hand lane again. This is shown by the solid line with arrows indicating the travel of a vehicle according to the preferred lane selection for fastest travel.
In this situation, the PND provides a lane selection instruction which will provide the fastest journey though the road section, rather than being one that is essential to follow a route e.g. to make a particular exit. In this instance, the PND will defer providing a lane instruction to the user to move from a middle lane to a left-hand lane until after the left-hand exit, determining that this is the appropriate timing using the lane speed profiles.
A lane selection recommendation may take into account other factors. For example in the illustrated section of road, there is a firm lane divider between the left-hand and middle lanes. Thus, if a driver moves too early to the left hand lane they will not be able to return to the left-hand lane. This may be taken into account when providing a recommended lane selection to a driver. This factor again makes it preferable to select the middle lane in the region before the left-hand exit to avoid being stuck in slow moving traffic as trucks take the left exit.
Accordingly, it may be seen that the detailed lane speed information in accordance with the invention may enable more useful guidance to provided to a driver via a navigation apparatus e.g. PND than simply to keep to a left-hand lane (for travel on the right-hand side of a road) in order to provide a fastest journey time. The PND may determine a lane selection through a road section, or along a route being navigated to result in the fastest travel along the route or through the road section, based on historical lane speed profile data, effectively resulting in local information regarding usual conditions being taken into account. The system may use the information to determine when to provide instructions to a user via a PND regarding a lane selection e.g. when to perform a lane manoeuvre i.e. to change lane, or when to maintain a current lane.
The Applicant has found that in particular in complex road sections where there are exits, entries, regulations and incidents, traffic flow speeds in different lanes may vary considerably, for example due to merging lane situations, temporary lane closures, exits that take the pressure out of the lane, truck overtaking prohibit situations, and incidents e.g. temporary lane closures. The method of the present invention enables a driver to be guided in a manner which may increase their rate of travel through such road sections.
Some other applications of historical lane speed profiles will now be discussed.
Another application of the invention may be to provide the user with guidance regarding the selection of lanes when passing through an interchange. The system may determine the lane having the greatest speed at the entry to the interchange, and the lane having greater speed at the exit of the interchange. A lane selection may be calculated providing the most efficient route from the quickest lane at the entrance of the interchange to the quickest lane at the exit of the interchange. The lane selection may be illustrated to the user via a display of the PND with a suitable graphical illustration.
Rather than providing a lane selection recommendation to result in a fastest route through a road section, or a fastest travel time along a route including the road section, other criteria could be taken into account. These criteria may be user specified criteria. For example, a user may specify that they do not wish to exceed a particular speed, or would prefer to be in a slower lane, one less heavily used by trucks etc. A suitable lane selection may be then provided to the user using the historical lane speed profiles.
Rather than providing lane guidance to a user, it may be desirable to simply provide information to a user of a PND regarding the likely lane speeds in a road section where the user is travelling, or about to travel. For example, a user may not be familiar with the road section, and may not know that while the left-hand lane is moving quite slowly, this should ease once a left-hand exit is passed. If a user is unaware of the likely traffic situation ahead, they may change lane repeatedly to try to move to an apparently faster moving lane. Such lane changes are known to have an overall negative effect on overall traffic flow, and it has been established that it is desirable to minimise the number of lane changes performed by drivers in congested zones to ease traffic flow. If a user is presented with information regarding the lane speed profiles ahead, they may be less likely to perform unnecessary lane manoeuvres, and may be reassured, reducing their stress levels. The user may make their own lane selection based upon the information or may be provided with a recommendation. Lane speed information may be presented to the user by displaying it on the digital map displayed by the PND e.g. as a map enhancement. For example, lane speed information could be superposed in any suitable form, e.g. in a text form, or graphically, for example using colours, or other graphical representations of a traffic flow per lane.
In addition to or alternatively to providing a recommendation to a user to change lane, a user may be provided with a recommendation to maintain a current lane. For example this might be the case in relation to the
The user could be instructed to leave a given, or larger or smaller gap to the next vehicle, or maintain a certain speed to minimise the elastic wave effect in a particular lane in order to improve overall traffic flow in the lane where lane level speed information suggests that this would be beneficial based on the historical profiles.
A further benefit of the present invention is that more accurate journey durations through the road section, and hence estimated times of arrival may be determined. The system will have detailed knowledge of the likely lane speeds to be encountered by a vehicle and may calculate a journey duration accordingly. Such possibilities are particularly beneficial in the context of trucking systems. Often trucks must travel in certain lanes. The system may have knowledge of regulations governing lanes used by trucks, making it possible to accurately determine the lane speed profiles for the lanes likely to be occupied by trucks. Professional drivers, such as truck drivers need to follow regulations and driving and rest times which specify that they may not drive longer than a certain number of hours without a break.
Another example of a situation in which the methods of the present invention may be of benefit is where a user needs to take a given exit e.g. a left hand exit in order to follow a planned route. Lane speed information may reveal that the driver's current lane is likely to have a relatively low lane speed up to and past this exit. The PND may then provide an instruction to the driver to move into the left-hand lane comparatively soon in order to maximise the time for them to make the lane change, given the difficulties resulting from the relatively slow traffic speed expected in their current lane.
In another example, a driver may be provided with an advance warning that there is likely to be heavy traffic i.e. low lane speeds in a lane merging with their current lane, or other such warnings based on the historical lane speed information. Such information may enable the user to prepare appropriately, for example by changing to another lane, or modifying their speed appropriately.
The methods and systems of the present invention may provide improved levels of safety, by providing greater driver awareness of expected speed levels affecting different lanes e.g. of a motorway, or of sudden lane speed decreases ahead using the historical lane speed profiles. The methods may also provide greater efficiency, by providing the ability for a user to select a most appropriate lane at an earlier stage, and keep to this lane, reducing the number of unnecessary lane changes, providing potential traffic flow improvements. This may also improve the fuel efficiency of driving, providing improved environmental benefits.
The methods of the present invention involve using historical rather than real-time lane speed profiles. However, as has already been established using road level systems, historical traffic information can be highly reliable in predicting the likely conditions a user will experience, and the present invention may therefore provide accurate and useful recommendations and information to a user which may help ease traffic flow, decrease levels of user stress and provide more efficient travel. As the historical lane speed profiles in accordance with the invention are based upon vehicle probe data, they may provide greater levels of flexibility and accuracy, and greater ease of calculation and processing.
Lane selection instructions may be provided to users via a PND in any manner, for example using audio or visual type instructions. Lane selection guidance may be similar to the guidance which is currently offered regarding the selection of a lane at an interchange to reach an appropriate destination.
While the invention has been described in relation to PND navigation devices, it will be appreciated that the invention is equally applicable to providing guidance via other types of navigation apparatus, including, for example, integrated in-vehicle navigation systems.
The steps of determining the lane speed profiles may advantageously be carried out by a central controller, which may also collect probe data. The steps of using the data to provide lane guidance or information or other functionality to a user via a navigation apparatus may be carried out be the central controller and/or a navigation apparatus. For example, instructions may be determined using the central controller and transmitted to a PND, or the PND may also carry out some processing of lane speed profiles. Other apparatus may also be involved in using the data in this manner to control a navigation apparatus, or for any other purpose.
A lane is a part of a carriageway of a road which is intended to be used by a single line of vehicles. A road will typically have at least two lanes, one for travel in each direction. Major roads may have more than one carriageway separated by a median, each of which may have multiple lanes. Lane changes occur during overtaking manoeuvres, or may occur in order to follow a given route e.g. to take an exit lane etc. Lane usage varies in different regions of the world. For example, in continental Europe the left hand lane is intended to be a fastest lane, while overtaking is normally carried out by passing a slower vehicle on its left side. The reverse applies in the UK where travel is on the left hand carriageway for a given direction of travel. In the US, drivers should stay in their given lane, which means that the left lane is not necessarily fastest. The historical speed profiles of the invention may be used for different purposes in different regions, depending upon local lane usage rules or customs.
| Filing Document | Filing Date | Country | Kind | 371c Date |
|---|---|---|---|---|
| PCT/EP10/70969 | 12/31/2010 | WO | 00 | 7/1/2013 |
