Safety and Operational Impacts of 53-Foot Truck-Trailers in Michigan

摘要

The interest in greater transport efficiency argues for permission to use longer trailers on the Michigan road system. The performance characteristics of 53' semitrailers were studied to determine whether penalties in cost or safety would accompany their introduction. Operated with the tandem axles in the full-rearward position, the larger offtracking of the 53' semitrailers is incompatible with the geometry of many intersections in Michigan. On the basis a maximum wheelbase of 40.5' (measured from kingpin to center of the tandem axles) is recommended. At this wheelbase, dynamic behavior at high speeds is comparable to that of other trailers currently in use on the road system, although further decreases in the wheelbase can degrade dynamic performance. When loaded to its full volume capacity the 53' semitrailer is expected to experience a slightly higher rollover frequency, but total rollover accidents would be unchanged due to the fewer number of trailers that would be required on the road. The ability to operate at greater weights is estimated to produce a 20 percent increase in pavement damage.