Roadway Widening Costs for Geometric Design Improvements To Accommodate Potential Larger Trucks

The substantial costs that could be required to accommodate potential future trucks on the existing roadway system are estimated. These costs have been shown to be sensitive to the size of the truck and the extent of the roadway system considered. Geometric requirements are considered for truck configurations that have greater offtracking and swept-path width than tractor-semitrailer combinations with a single 14.6-m (48-ft) trailer (longer combination vehicles). The truck configurations evaluated include larger tractor-semitrailers, Rocky Mountain doubles, B-train doubles, turnpike doubles, and triples. The extent and cost of roadway widening that would be necessary to accommodate the larger trucks are considered for horizontal curves on mainline roadways and interchange ramps and for ramp terminals and at-grade intersections. Potential costs also are included to provide staging areas to accommodate larger multitrailer trucks and the cost savings in geometric improvements that might be required if staging areas were provided. Tables illustrate both the estimated extent of geometric design improvements and the cost of those improvements to accommodate particular truck configurations on particular roadway networks. These costs have been estimated for truck configurations that are larger than the 14.6-m (48-ft) tractor-semitrailer combination that was used as the baseline vehicle for the study.