Patent Application
20230018669
N/A
N/A
A variety of traffic calming techniques are in use, including traffic roundabouts and lane markers. A traffic roundabout (also termed traffic circle or rotary) is a central island located at the intersection of several vehicle roadways around which vehicles entering from the roadways flow in a circular pattern. Roundabouts offer several benefits to traffic flow. Traffic congestion can be reduced compared to all-way-stop-sign and traffic light-controlled intersections. The speed of approaching vehicles can be reduced, providing gaps for entry of minor-road traffic.
Miniature roundabouts (mini-roundabouts) are characterized by a small diameter central circle with traversable central and splitter islands. Mini-roundabouts can double traffic-handling capacity compared to 4-way stop sign control. They can cost less than larger roundabouts by eliminating land purchase or utility/drainage relocation. Mini-roundabouts can result in greater safety for drivers, pedestrians, and bicyclists. They offer most of the benefits of larger diameter, non-traversable roundabouts with the added advantages of smaller footprint and lower cost, making them attractive improvements for many two- and three-lane intersections.
Many municipalities are employing safe street techniques such as speed bumps or humps, curb extensions, crossing islands, high visibility painted pavement markings, signage, lighting, and lanes specifically designated for bicyclists, pedestrians, and/or public transportation vehicles such as buses. Such techniques are intended to slow vehicle traffic and make streets more accessible to a variety of modes of travel and uses.
A modular block system for miniature roundabouts is described in WO 2017/044734 and US 2019/0040589. A modular roundabout with interconnectable boards is described in US 2020/0087867. In these roundabout systems, all or many of the boards, both perimeter boards and filler boards, are fastened to the ground surface, typically with two to four anchors per board. The number of boards in such roundabouts can range from about 12 to about 10,000 boards. This results in a large amount of material and a significant number of anchors. The anchor installation process can be the most time-consuming portion of the installation process.
Expediently installable traffic calming systems and methods of installation are provided. The traffic calming system can remain in place on the ground without additional attachment while a vehicle grazes or traverses it. The traffic calming system can be installed rapidly and can be removed rapidly. The traffic calming system can be used for temporary installations, such as a construction site or after a natural disaster, where temporary redirection of traffic may be appropriate. The traffic calming system can be used in situations that involve a loss of power and/or limited availability of emergency response personnel to direct traffic at uncontrolled intersections.
The traffic calming system includes a variety of modular units that can be laid out in any desired pattern as needed to direct a flow of traffic. In some embodiments, the modular units can be connected together in an arrangement such as for a roundabout or splitter island. In some embodiments, the modular units can be arranged individually as lane markers, such as for a bicycle lane or pedestrian lane, or to outline a roundabout or splitter island. In some embodiments, a modular unit can be used singly, such as for a reflective marker or to hold a sign. The modular units can surprisingly remain in place on the ground surface as vehicles graze or traverse over them without the need for additional ground attachment, such as ground anchors or an adhesive, and/or without the need for many additional modular units in the interior of an arrangement of connected modular units.
The traffic calming system can be installed rapidly and can be removed rapidly. The system is suitable for temporary installations, such as at a construction site or after a natural disaster, where temporary redirection of traffic may be appropriate. The system can be used for semi-permanent installations, such as for marking lanes during warm weather months, while allowing the system to be readily removed during winter months so that it does not interfere with snowplowing. The system can also be used for permanent installations. In some permanent installations, additional anchoring mechanisms can be used.
In some embodiments, the system can be used in a short term temporary installations with only a friction enhancement on the lower surface to remain in place. In some embodiments, the system can be used in a longer term temporary installation, with anchors that do not require bonding and are easily removable. In some embodiments, the system can be used in a permanent installation, with anchors bonded to the ground.
Further embodiments, aspects, and features include the following:
a body configured for placement on a ground surface, the body comprising an upper surface, a lower surface, and a side surface between the upper surface and the lower surface; and
wherein:
a plurality of the lane markers of any of 1-13, the lane markers arranged in a pattern on a roadway surface of asphalt or concrete, and
wherein the pattern comprises a roundabout, a splitter island, a bicycle lane, or a pedestrian lane.
a skeletal structure comprising:
wherein:
providing the traffic calming system of any of 15-27; and
installing the boards in the skeletal pattern on the ground surface at an intersection of vehicle roadways.
providing the lane marker of any of 1-13; and
installing the lane marker on the ground surface.
providing a plurality of the lane markers of any of 1-13; and
installing the lane markers in a pattern on the ground surface.
Reference is made to the following detailed description taken in conjunction with the accompanying drawings in which:
In some embodiments, a traffic calming system can include one or more lane markers that can be located individually or in a group on a ground surface. The lane marker can surprisingly remain in place on a roadway surface of asphalt or concrete as a vehicle grazes or traverses the lane marker without the need for additional attachment, such as anchors or adhesive. The lane marker can have a variety of configurations in plan view, such as circular, sometimes referred to as a dot, or rectangular, such as a board.
Referring to
Referring to
When the load is applied at another angle to the surface, the load (indicated schematically at A in
Another component specific to the lane marker is the height of the leading edge, or the height of the upper edge of the side surface (the dimension between the lower surface and the upper surface), along the portion of the marker likely to be impacted by a vehicle tire. Vehicles have different diameter tires, and the load components on the marker can vary depending on how each tire diameter interacts with the geometry of the lane marker. The leading edge can be located at a height at which a tire of a particular diameter does not contact the leading edge, but rather contacts the sloped upper surface, which yields the same load components (normal, parallel) regardless of tire diameter. However, if the leading edge is sufficiently high, it can receive tire contact first, before the tire contacts the sloped surface. In this case, the tire diameter can yield different load components, with larger tire diameters being better for achieving the goal of no movement (or less lateral load). Since the friction load and lateral load are both a function of the applied load of the vehicle, the vehicle's weight is not determinative, and only the ratio of the two loads determines if the lane marker moves.
Thus, the height of the leading edge and the angle of the upper surface at the leading edge can be selected to decrease the lateral force component and increase the downward force component, thereby increasing the frictional force component relative to the lateral force component. Additionally, the static coefficient of friction of the lower surface of the lane marker can be selected to increase the magnitude of the frictional force. In this manner, the lateral force component of the tire can be offset by the frictional force on the lower surface, and the marker can remain in place.
An analysis was performed based on a lane marker configuration as illustrated in
For example, for a static coefficient of friction of 0.25, the sum of the lateral force components (the tire lateral force component and the frictional force component) is equal to −2%. Since this number is negative, the lane marker does not move.
In this analysis, a CoF of 0.25 results in a negative resultant lateral load because the angle is so shallow, and the majority of the vehicle's weight is applied normally to the friction surface as opposed to laterally (about a 4-1 ratio). However, other factors can also affect the coefficient of friction of the lower surface of the lane marker in the field. For example, the ground surface can be wet or can be coated with debris such as loose dirt or sand particles. The lane marker can degrade over time. Thus, the coefficient of friction of the friction enhancement of the lane marker can be selected to account for such variables. For example, in some embodiments, a CoF can be provided to generate at least a −50% resultant load to provide a margin for a change in the CoF over time.
In some embodiments, the angle of the upper surface can range from 5° to 30° with a tolerance of ±5%. In some embodiments, the angle of the upper surface can range from 5° to 25° with a tolerance of ±5%. The angle is constant from the leading edge to at least a distance of 2 inches from the center or from a highest location of the marker. The maximum height of the lane marker is 2 inches ±5% and is preferably no greater than 3 inches ±5% to remain below the lowest vehicle clearance allowable under the Federal Highway Administration regulations. However, greater heights may be used, depending on the application. In some embodiments, the angle of the upper surface is less than 30° with a tolerance of ±5%. It will be appreciated that the larger the angle, the greater the lateral load component, tending to result in movement of the lane marker when impacted by a vehicle.
In some embodiments, the height of the leading edge of the lane marker, or the dimension of the side surface between the lower surface and the upper surface, is less than 2 inches with a tolerance of ±5%. In some embodiments, the height of the leading edge can range from 0.0625 inch to 2.0 inches with a tolerance of ±5%. The side surface is preferably vertical or orthogonal with respect to the ground surface with a tolerance of 5%. In some embodiments, the height of the leading edge can be less than 0.625 inch; however, this can result in an edge that is too sharp and subject to excessive wear from impacts.
In some embodiments, the lower surface has a static coefficient of friction of at least 0.25 ±5% with respect to a ground surface of asphalt or concrete. In some embodiments, the lower surface has a static coefficient of friction of least 0.75 with respect to a ground surface of asphalt or concrete. In some embodiments, the static coefficient of friction is at least 0.25, at least 0.5, at least 0.75, at least 1.0, at least 1.25, at least 1.5, at least 1.75, or at least 2.0, with a tolerance of ±5%. The static coefficient is typically greater than a dynamic coefficient of friction. To minimize sliding of the lane marker should it start moving, in some embodiments, the dynamic coefficient of friction is within 20% of the static coefficient of friction. In some embodiments, the dynamic coefficient of friction within 5% of the static coefficient of friction.
The coefficient of friction can be determined by several factors, including the surface topography or texture, how the surface behaves under deformation, the hardness of the surface material, and similar characteristics of the mating surface (e.g., the road surface).
In some embodiments, a friction enhanced lower surface can include a texture on the lower surface of the lane marker. For example, the lower surface 30 can be formed with multiple upraised portions 32 arranged in any suitable pattern. In some embodiments, upraised portions have a dimension of at least 0.005 inch ±5%.
One example of a suitable pattern is shown in
In some embodiments, a friction enhanced lower surface can be fabricated with an elastomeric material having a Shore A hardness of 90 or less, 80 or less, 60 or less, or 40 or less. In some embodiments, a friction enhanced lower surface can be fabricated with an elastomeric material having a Shore D hardness of 75 or less. In some embodiments, the material can be a urethane material or a rubber material.
In some embodiments, the body, the upper body, and/or the lower body of the lane marker can be fabricated from a thermoset or thermoplastic elastomer, urethane, thermoplastic olefin, ethylene propylene diene monomer (EPDM), nitrile, amide, or polyester-based elastomer. In some embodiments, the body, the upper body, and/or the lower body of the lane marker can be fabricated from a polymer material or a metal or metal alloy material, or combinations thereof. In some embodiments, the upper body of the lane marker can be fabricated from a polymer material such as polyvinyl chloride (PVC) or acrylonitrile butadiene styrene (ABS). In some embodiments, the friction enhanced lower surface can be fabricated with a material having a hardness less than the hardness of the upper body of the lane marker. In some embodiments, the body or the upper body of the lane marker is fabricated from a material that can be driven over without cracking or breaking.
A lane marker can have a variety of configurations in plan view, such as circular, sometimes referred to as a dot, or rectangular, such as a board. In some embodiments, a circular lane marker or dot can have a conical shape with a circular configuration in plan view rising to a maximum height at the center (as in
The lane markers can be laid out by a suitable lay-out machine that can place them at suitable intervals. Lane markers with a circular plan configuration can be laid out in any orientation. The lane markers can also be picked up by machine. The lane markers can also be laid out and/or picked up manually.
The lane markers can be laid out in any desired pattern to direct the flow of traffic. For example, lane markers can be used to demarcate a roundabout, a splitter island, a bicycle lane, a pedestrian lane, a traffic diverter, or a lane divider.
The lane markers can be used in permanent installations or in temporary installations. In some embodiments, the lane marker can also be affixed to the ground surface with another mechanism, such as ground anchors, adhesive, or magnetic fasteners. The lane marker can include an opening therein for a ground anchor.
In some embodiments, the lane marker can include an opening in the upper surface to hold a vertical marker, delineation post, reflector, light, or sign.
In some embodiments, the lane marker can be solid. In some embodiments, the lane marker can be hollow. In some embodiments, the lane marker can include a hollow interior that can be filled with another material, such as water, sand, or recycled materials. Recycled materials can include recycled car tires.
In some embodiments, the lane marker can house electronic components or sensors. In some embodiments, the lane marker can house a solar or piezoelectric energy generator. In some embodiments, the lane marker can house smart devices to enable communication with other smart devices, such as in a bus, car, truck, bicycle, or a communication hub. In some embodiments, the lane marker can communicate with other lane markers to control attached features such as lights, signs, and reflectors.
The roundabout can surprisingly be driven over after installation without shifting on the ground surface and without the need for additional attachments to the ground surface, such as ground anchors or an adhesive. The roundabout can surprisingly be driven over after installation without the need for any additional boards in the interior of the roundabout. The roundabout system can handle lateral loading on the perimeter from vehicles that graze or traverse the roundabout.
The boards can be arranged in any desired skeletal pattern. For example, the perimeter boards, which can be trapezoidal in plan view, can be arranged in any polygonal pattern, such as hexagonal, octagonal, or dodecagonal. The trapezoidal boards can be arranged as straight-line segments of arcs of a circle, to form a generally circular roundabout of any diameter. The interior boards can be arranged to also connect to the joints between adjacent perimeter boards to provide cross bracing, thereby stabilizing the skeletal structure. Typically, at least three boards are connected at a joint to stabilize the boards in the skeletal pattern. Portions between the boards within the area of the skeletal pattern can be left free of other boards.
Connectors 150 are provided to attach ends of adjacent boards together at the joints to form the desired pattern. More particularly, end regions of each board are shaped to abut end regions of one or more adjacent boards. A connector is attached to each of the end regions of the adjacent abutting boards, thereby connecting the boards at a joint.
In some embodiments, a connector 150 can be a plate that overlies each of the end regions of adjacent boards. See
It will be appreciated that other configurations of the end regions of the boards can be used. Similarly, a different number of radial boards can be used, for example, for smaller or larger roundabouts.
In some embodiments, a recess, which can have a complementary shape with each portion of the connector, can be machined or molded into the upper surfaces of the boards to form a seat for each portion of the connector so that the connector is flush or below the surrounding upper surface. In some embodiments, the connector can be mounted on the surface with no recess.
Any suitable fasteners can be used to attach the connectors to the boards. In some embodiments, fasteners can include bolts or screws and washers. In some embodiments, apertures for the fasteners can be predrilled in the boards, and in some embodiments, no pre-drilling is required to install the fasteners. In some embodiments, apertures can include wider portions for sub-flush washers. In some embodiments, the fasteners can be taken out and replaced multiple times with no or minimal loss in thread strength. For example, the connectors can be readily removed to replace a damaged board or section of boards or to remove the roundabout.
Fastening the connectors from above to the upper surface of the boards, as illustrated in
In some embodiments, the connector can be provided as a bar at a midplane of the board thickness between the upper and lower surfaces. Fasteners, such as bolts or screws, can go through aligned apertures in the board and the bar. Midplane bars are illustrated schematically in
The connector can have any suitable configuration. In the embodiments shown, the connector is configured as a rectangular plate or bar. In some embodiments, the connector can have other configurations, such as, without limitation, a square shape, a dovetail shape, a T-shape, an I-shape, or a dog-bone shape.
The traffic calming system can be placed on top of any suitable supporting ground surface, such as a road surface of asphalt or concrete. The traffic calming system can be installed over existing pavement with no modification to the existing pavement. The traffic calming system can be installed relatively rapidly, more quickly than traditional roundabouts, resulting in minimal traffic disruption.
In some embodiments, additional friction enhancements can be applied to or formed in or on the lower surface of the modular units, as described above with respect to the lane marker. Friction enhancements can include a textured surface on the lower surface of the modular unit. In some embodiments, a textured surface can be molded into the unit during fabrication. In some embodiments, a textured surface can be applied to the lower surface of the unit, as illustrated in
The components of the traffic calming system can be fabricated off site in advance and shipped to the installation site as a kit. The components (e.g., boards, connector plates, and fasteners) can be palletized and, in some embodiments, can be movable using a single forklift vehicle. See
Optionally, the modular units can also be anchored to the ground via ground anchors if desired. One or more apertures can be provided in the units for this purpose. For example,
In some embodiments, the modular units can be formed into other configurations and skeletal patterns, in addition to a generally circular roundabout. For example, boards can be formed into a splitter island, which can have a variety of configurations, such as triangular, trapezoidal, rectangular, and square and combinations thereof. The configuration can depend on the traffic conditions and roadway type, size, and application. For example, a splitter island configuration can include a long rectangular section with a widened rounded section at one end. Perimeter boards can be arranged and connected to define the perimeter, and interior boards can be arranged and connected as cross members within the perimeter to stabilize the skeletal structure.
The modular units, e.g., boards and or lane markers, can be made of any suitable material. In some embodiments, a polymer material can be used. The material can be elastomeric, thermoplastic, or a combination of thereof to achieve desired characteristics. A material that can be driven over without damage can be used.
Suitable material compositions can include one or more of a polyolefin, poly(methyl methacrylate), acrylonitrile butadiene styrene, polyethylene terephthalate (PET), polybutylene terephthalate, polycarbonate, polyamide, and polyoxymethylene. In some embodiments, polyolefins such as polypropylene (PP), polyethylene (PE), or high density polyethylene (HDPE) can be used as a base polymer. In some embodiments, engineering polymers such as polyethylene terephthalate (PET) or polyamide (Nylon) can be used as a base polymer. In some embodiments, the modular units can be made from recycled and/or recyclable materials. In some embodiments, crumb rubber (CR), obtained from recycled tires, can be used as an additive to a base polymer. In some embodiments, a thermoplastic urethane or polyurethane (TPU) can be added to improve toughness, particularly to PET. In some embodiments, the units can be made of primarily high density polyethylene (HDPE) with the addition of fiber reinforcement, such as fiberglass, added for stiffness and strength. In some embodiments, the units can be made of HDPE with no additional fiber reinforcement.
Modular units can be manufactured in any suitable manner, such as by molding, an extrusion process, or a pultrusion process. In some embodiments, the units can be produced by a molding process, such as compression molding, which uses high pressure to force a thermoplastic material into a tool. The process can be selected as appropriate for the application, accounting for factors such as large complex parts and extremely high viscosity resins. A mold for each size and shape of unit can be provided. In some embodiments, board stock from suitable materials is also commercially available in a variety of sizes and lengths and can be purchased. Multiple boards can be cut to appropriate sizes from a single longer board.
Connectors for connecting the modular units together can be made from any suitable material. In some embodiments, the connector can be made from a metal or metal alloy. In some embodiments, the connector can be made from a urethane rubber. In some embodiments, the connector can have a hardness ranging from about Shore Hardness 30 A to about Shore Hardness 50 D. In some embodiments, the connector can have a Shore 90 A hardness. In some embodiments, a connector plate can have a thickness that can range from 1/16 inch ±5% to 2.5 inches ±5%. In some embodiments, the connector can be 0.5″ thick ±5%.
A traffic calming system as described herein can be placed on top of any suitable supporting surface. In some embodiments, the roundabout can be placed directly over an existing road surface, for example, of asphalt or concrete. The traffic calming system be installed over existing pavement with no modification to the existing pavement.
The traffic calming system can be used for a variety of applications such as roundabouts, splitter islands, perimeter islands, bicycle lanes, pedestrian refuge areas, elevated platforms, and speed mitigation.
A traffic calming system as described herein can be installed relatively rapidly, often more quickly than traditional traffic calming, resulting in minimal traffic disruption. The traffic calming system can be driven over after installation. In some embodiments, installation time can be reduced by 75%, 85%, 90% or 95% using this system and method. In some embodiments, the cost of fabricating and installing a traffic calming system can be reduced by 25%, 50%, 75%, 85%, 90% or 95%.
A traffic calming system as described herein can have minimal maintenance costs. If a modular unit is damaged, it can be replaced easily and quickly. The traffic calming system does not need to be painted. Modular units can be manufactured in a variety of colors and any desired color scheme can be selected.
As used herein, “consisting essentially of” allows the inclusion of materials or steps that do not materially affect the basic and novel characteristics of the claim. Any recitation herein of the term “comprising,” particularly in a description of components of a composition or in a description of elements of a device, can be exchanged with “consisting essentially of” or “consisting of.”
It will be appreciated that the various features of the embodiments and aspects described herein can be combined in a variety of ways. For example, a feature described in conjunction with one embodiment or aspect may be included in another embodiment or aspect even if not explicitly described in conjunction with that embodiment or aspect.
To the extent that the appended claims have been drafted without multiple dependencies, this has been done only to accommodate formal requirements in jurisdictions that do not allow such multiple dependencies. It should be noted that all possible combinations of features that would be implied by rendering the claims multiply dependent are explicitly envisaged and should be considered part of the invention.
The present technology has been described in conjunction with certain preferred embodiments and aspects. It is to be understood that the technology is not limited to the exact details of construction, operation, exact materials or embodiments or aspects shown and described, and that various modifications, substitution of equivalents, alterations to the compositions, and other changes to the embodiments and aspects disclosed herein will be apparent to one of skill in the art.
