| Improved highway networks result in net benefits to society. A principle benefit of highway improvement is the reduction of user travel time while in the network. Assigning a value to travel (or delay) time is a difficult task since highways are used by a myriad mix of individuals, each of whom values his or her time differently. While the wage rate method of valuing user time is convenient, new, alternative approaches based on leisure or survival should be considered. This new avenue of thinking appears to be applicable and somewhat consistent with conventional practices. This leads to the thinking that local statistical information concerning the user value of time should be incorporated into benefit/cost calculations to more rationally represent the local user population. Even though users experience benefits once a project is completed, there can be considerable user delay costs for lane closures and/or detouring associated with construction and subsequent maintenance that are neglected from the initial benefit/cost analysis. Due to its economic as well as social complexity, alternative measures of user travel time valuation and its network effects need to be considered. User benefit software are a useful resource for highway project evaluation but can be highly sensitive to input parameters. The interaction of discount rate, value of time, and analysis period need to be understood in order to assure a valid analysis as well as to accurately understand the sensitive behavior of these interactions. |
