REAR and side underride have been required on commercial vehicles in the United Kingdom since 1986. Front underride is being discussed now, and regulations may be announced as early as 1999.
Has underride saved any lives in the United Kingdom? Bob Stacey, technical manager at the Road Haulage Association, says it's hard to know for sure. Statistical proof is lacking.
Still, virtually all commercial vehicles above 3.5 tonnes (7,700 pounds) gross vehicle weight must have the devices. The rear underride device is designed to absorb the impact of an automobile, but the side guards are just for pedestrians and bicyclists.
The regulation has a certain amount of flexibility and allows manufacturers to incorporate lighting assemblies and other systems into the rear underride. The variety was very evident in the tank trailers on display at TankCon 97 held in June in Derby, England.
Rear underride adds perhaps 100 pounds to British tank trailers, which is about the same for US tank trailers. Some tank operators have had difficulties as a result of reduced ground clearance on tank trailers equipped with rear underride. The lower bar sometimes gets knocked off when trailers are loaded on ferries.
The underride devices must be maintained. The rule states that the device shall be maintained free from any obvious defect that would be likely to adversly affect performance in the event of a rear impact.