FEDERAL-AID POLICY GUIDE
September 30, 1992, Transmittal 5
NS 23 CFR 658
OPI: HIA-20
(1) For example, a minimum lane width requirement of 12 feet would automatically eliminate a significant number of roads that may be able to safely accommodate STAA-dimensioned vehicles for purposes of access. The truck access study conducted by the Transportation Research Board (TRB) found that lane width has only a minor effect on the safe operation of STAA-dimensioned vehicles except for lane widths of 10 feet or less.
(2) Likewise, a 4-foot shoulder width requirement would automatically eliminate a large number of roads that would be able to safely accommodate STAA-dimensioned vehicles. Many States across the country permit operation of STAA-dimensioned vehicles on sections of road with lane widths less than 12 feet or without 4-foot shoulders; therefore, we find the absolute application of a 12-foot lane width or a 4-foot shoulder width provision unacceptable. The Federal regulation specifically attempts to direct the States to implement access policies which are consistent with the ability of the proposed route to accommodate the vehicle.