Truck Escape Ramps

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.

"Many state departments of transportation (DOTs) build and operate escape ramps to allow heavy trucks that cannot maintain safe speeds on steep downgrades to safely exit the highway instead of losing control and crashing. Some escape ramps use upward-sloping beds of loose aggregate to slow the vehicles, while others employ passive or active mechanical devices such as cables to slow the vehicles. Some agencies use intelligent transportation technologies to detect trucks that are driving at excessive speeds for the location and to provide information to truckers regarding emergency escape ramp locations.NCHRP Synthesis 621: Truck Emergency Escape Ramp Design and Operation, from TRB's National Cooperative Highway Research Program, documents practices used by state DOTs to design and operate facilities to detect, guide, and capture out-of-control vehicles travelling on steep downgrades." -- publisher's website.