Text Size:  | Share:

The fundamental problem involved in evaluating proposals for changes in truck dimensions is that their effects can often only be estimated or modeled. The data available for estimating safety consequences in particular are inadequate and probably always will be. Thus, the committee that conducted the study on federal policies regarding commercial vehicle dimensions (whose findings with regard to productivity were discussed earlier in the section on productivity-enhancing truck regulation) concluded that the resulting analyses usually involve a high degree of uncertainty. What is needed is some way to evaluate potential changes through limited and carefully controlled trials, much as proposed new drugs are tested before being allowed in widespread use.

The fundamental problem involved in evaluating proposals for changes in truck dimensions is that their effects can often only be estimated or modeled. The data available for estimating safety consequences in particular are inadequate and probably always will be. Thus, the committee that conducted the study on federal policies regarding commercial vehicle dimensions (whose findings with regard to productivity were discussed earlier in the section on productivity-enhancing truck regulation) concluded that the resulting analyses usually involve a high degree of uncertainty. What is needed is some way to evaluate potential changes through limited and carefully controlled trials, much as proposed new drugs are tested before being allowed in widespread use.

The committee recommended that a new independent entity be created to work with private industry in evaluating new concepts and recommending changes to regulatory agencies (Special Report 267: Regulation of Weights, Lengths, and Widths of Commercial Motor Vehicles; TRB 2002). Limited pilot tests would be required, which would need to be carefully designed to avoid undue risk and ensure proper evaluation. Special vehicles could be allowed to operate under carefully controlled circumstances, just as oversize and overweight vehicles are allowed to operate under special permits in many states. Changes in federal laws and regulations would be required to allow states to issue such permits on an expanded network of highways, under the condition that a rigorous program of monitoring and evaluation be instituted.