Speed Limiting Apparatus

The present disclosure relates to the field of traffic control and safety devices. More specifically, it relates to apparatuses designed for traffic calming, particularly for limiting the speed of vehicles in designated areas.

Controlling vehicle speed is a critical aspect of ensuring safety in residential areas, school zones, parking facilities, and other locations with pedestrian traffic or specific speed regulations. The most common device used for this purpose is the speed bump, also known as a speed hump or traffic calmer.

Traditional speed bumps are typically constructed from asphalt, concrete, solid rubber, or plastic. They present a fixed vertical obstacle in the roadway that forces vehicles to slow down to avoid occupant discomfort and potential vehicle damage. Their static and rigid nature means they affect all vehicles equally. A vehicle traveling at or below the desired speed still encounters a jarring impact with the speed bump. Although a high-speed vehicle may risk damage, this can lead to an unnecessarily uncomfortable experience for compliant drivers and their passengers.

A speed bump's abrupt obstacle can cause damage to a vehicle, particularly those with low ground clearance or stiff suspension systems. They also pose an impediment to emergency vehicles, such as ambulances and fire trucks, where response time is critical. The passage of these heavy vehicles over rigid bumps can cause discomfort to patients being transported and potentially damage sensitive equipment. The noise generated by vehicles, especially larger trucks, traversing these bumps can be a source of disturbance for nearby residents. Installation and removal of these permanent or semi-permanent structures can also be costly, labor-intensive, and disruptive to traffic flow.

More complex, active, or automated systems have been proposed. Such systems may involve sensors to detect vehicle speed and mechanical or hydraulic actuators to raise an obstacle. However these solutions are often mechanically complex, expensive to install and maintain, and require a power source. Their reliance on electronic sensors and moving parts makes them susceptible to failure in adverse weather conditions, or the results of wear and tear or vandalism.

There is an unmet need in the art for a traffic-calming device that can effectively differentiate vehicle speeds, is passive in its operation, and does not use complex electronics or mechanical actuators.

The present invention is an apparatus for moderating the speed of a vehicle. A non-Newtonian fluid is encased in a durable, flexible enclosure. The enclosure may be any of a range of rubber, castable elastomers, or flexible polymers such as high-density polyethylene (HDPE).

Among appropriate non-Newtonian fluids, shear-thickening fluids are known to increase their viscosity when subjected to high-shear force. Encased in a flexible enclosure to form, for example, a road obstacle, such a fluid would deform to slow yet allow passage of a slow-moving vehicle. A fast-moving vehicle, however, would hit the obstacle with more force, encountering the non-Newtonian fluid as a solid mass. The properties of non-Newtonian fluids could be employed to make effective speed bumps.

Bingham plastic is a non-Newtonian fluid having the opposite effect. When impacted at low stress, it responds as a rigid solid. At high stress, it responds as a viscous fluid. A flexible road obstacle containing Bingham plastics could be effective at controlling traffic to move at a steady pace.

Viscoelastic fluids, when deformed, exhibit both viscous and elastic characteristics. Viscoelastic fluids can absorb and dissipate energy. A speed-limiting apparatus containing viscoelastic fluid may ease the usual discomfort of speed bumps when encountered at lower speeds, and at higher speeds, slow a vehicle by absorbing energy.

The non-Newtonian fluid is contained in a housing and is characterized by a specific impact threshold, below which it behaves as a liquid and above which it behaves as a solid.

A first embodiment is a form that is higher than a road surface. A vehicle approaching the apparatus at a low speed imparts an impact force below the threshold, causing the fluid to remain in its liquid state. This allows the vehicle's wheels to depress into the apparatus, thereby passing over the apparatus with little to no resistance. A vehicle approaching the apparatus at a high speed imparts an impact force above the threshold, causing the fluid to behave as a solid, thus impeding or stopping the vehicle's movement.

A second embodiment is a form that is lower than a road surface. A channel in the surface houses a membrane form containing a non-Newtonian fluid. A vehicle approaching the apparatus at a low speed imparts an impact force below a specific impact threshold, causing the fluid to remain in its liquid state. This causes the vehicle's wheels to depress into the membrane, falling into the channel of the apparatus, slowing or stopping the vehicle. A vehicle approaching the apparatus at a high speed imparts an impact force above a specific threshold, causing the fluid to behave as a solid, allowing the vehicle to pass over the apparatus with little to no resistance.

shows an example embodiment wherein a flexible membranecreates a form. In some embodiments the form is tapered at the edgesand relatively thicker in its center. The formis configured to contain a non-Newtonian fluid.

shows a cross-section wherein the flexible to semi-flexible membranehas a relatively flat bottom surface, tapered edges, and an interior spacefor containing a non-Newtonian fluid. The form protrudes from the road surface. The non-Newtonian fluid has an impact threshold. Beneath that threshold, the non-Newtonian fluid behaves like a liquid; above it, the fluid behaves like a solid. At a speed delivering an impact beneath the threshold, the wheels of a vehicle passing over the embodiment encounter the non-Newtonian fluid as a liquid, and pass with minimal resistance over the embodiment. Conversely, at a speed that delivers an impact above the threshold, the wheels of a vehicle passing over the embodiment will encounter the non-Newtonian fluid as a solid, and pass with maximum resistance against the embodiment.

andshow an example iteration of the embodiment;is a perspective view andis an exploded view. A flexible membranecontains a non-Newtonian fluid. The flexible membranecontaining the non-Newtonian fluid is housed in a rigid formhaving a channelconfigured to contain and support the flexible membrane.

The non-Newtonian fluid has a threshold impact. Beneath it, the non-Newtonian fluid behaves like a liquid; above it, behaves like a solid. At a speed delivering an impact below the threshold, the wheels of a vehicle passing over the embodiment encounter the non-Newtonian fluid as a liquid, dropping into the channel, which slows or stops the vehicle. At a speed delivering an impact above the threshold, the wheels of a vehicle passing over the embodiment encounter the non-Newtonian fluid as a solid and pass over the embodiment unimpeded.