Emergency escape ramps are usually located in mountainous areas which cause high construction costs and present difficult site selection. Designs include: •
Arrester bed: a gravel-filled ramp adjacent to the road that uses
rolling resistance to stop the vehicle. while setting a standard for bed material in the US. •
Gravity escape ramp: a long, upwardly inclined path parallel to the road. Substantial length is required. Control can be difficult for the driver; problems include rollback after the vehicle stops. •
Sand pile escape ramp: a short length of loosely piled sand. Problems include sudden, forceful deceleration; sand being affected by weather conditions (moisture and freezing); and vehicles vaulting and/or overturning after contacting the sand pile. •
Mechanical-arrestor escape ramp: a proprietary system of stainless-steel nets transversely spanning a paved ramp to engage and retard a runaway vehicle. Ramps of this type are typically shorter than gravity ramps, and can work even on a downhill grade. These systems tend to be costly, but may save expensive real estate in crowded areas and prevent even more costly crashes. One such ramp at
Avon, Connecticut in the United States has an electrically heated pavement surface to prevent snow and ice accumulation. •
Alternatives: such as a vehicle arresting barrier. ==Location==