A runaway truck ramp, runaway truck lane, escape lane, emergency escape ramp or truck stopper bearing is a traffic device that enables vehicles with braking problems to stop safely. It is usually a long sand - or gravel filled lane attached to a steep downhill gradient designed to accommodate a main road section and a large truck or bus. The ramp allows the kinetic energy of a moving vehicle to be distributed gradually in a controlled and relatively harmless manner, helping the operator to stop safely without a violent collision.
Emergency escape ramps are often located in mountainous areas with high construction costs and difficult location selection. [1] A ramp can cost $ 1 million.
Surge arrester bed: a gravel-filled ramp adjacent to the road that uses the rolling resistance to stop the vehicle. [1] The required length of the bearing depends on the mass and speed of the vehicle, the grade of the surge arrester and the rolling resistance provided by the gravel. [3]
Gravity escape ramp: a long, upward sloping road parallel to the road. Considerable length is required. Control can be difficult for the driver; problems include rolling back after the vehicle has stopped.
Sand pile escape ramp: short length loosely stacked sand. Problems include sudden, strong slowing down; weathering (humidity and freezing) of sand; and vehicles that jump and / or tip over after contact with the sand pile.
Mechanical stopper escape ramp: A special system consisting of stainless steel nets that extend across a coated ramp to activate and delay a runaway vehicle. These types of ramps are typically shorter than gravity ramps and can operate even on a downhill slope. [4] These systems tend to be costly, but can save expensive real estate in crowded areas and prevent even more costly accidents. In Avon, Connecticut, in the United States, such a ramp features an electrically heated sidewalk surface to prevent snow and ice accumulation. [5]
Alternatives: like a vehicle stop barrier.