This synthesis will be of interest to highway design engineers, maintenance personnel, safety and enforcement officials, traffic engineers, and others responsible for the safe operation of large trucks on highways. Information is provided on the critical aspects of site location, design criteria, and maintenance procedures, and their relationship to truck escape ramp performance. The safety of truck drivers, other road users, and occupants of roadside properties is often imperiled by the combination of heavy trucks and steep downgrades on highways. Frequently, gearing down, applying the brakes, and using the retarding power of the engine are not sufficient to control the truck, and serious crashes can result. Many states have constructed truck escape ramps to safely remove runaway trucks from the traffic stream. This report of the Transportation Research Board provides information on the location, design, construction materials, geometrics, and construction costs of truck escape ramps. Operational considerations, such as descriptions of advance warning signs, traffic control devices at the ramp, and vehicle removal procedures are described. Information on frequency and type of usage, maintenance of the ramps, and driver-related issues is also included. (A)
Abstract