The project developed a new roughness index and presented a methodology for conducting life-cycle cost analysis.

There is consensus among those involved in managing the nation's highway systems that pavement-investment strategies must consider both user and agency measures of pavement quality. Conventional user-oriented measures of pavement serviceability are based on automobile-occupant reaction to pavement condition. Such measures do not reflect the full range of vehicle classes, and their relationship to user costs is not well defined. A more useful measure would incorporate both pavement condition and user costs for all vehicle classes. User costs consist of vehicle-operating costs for the full range of vehicle classes (automobiles, buses, and light and heavy trucks); costs of delays due to construction/maintenance work zone activities; costs of transporting goods over the full spectrum of pavements; and costs attributable to driver and passenger discomfort. Therefore, there is a need to develop an improved pavement-investment decision methodology that incorporates user costs, condition measures, and agency inputs and that can also be integrated into pavement management systems.

The research reviewed literature on the relationships between user costs and pavement roughness, developed a new roughness index, and presented on a CD-ROM a method for conducting life-cycle cost analysis. However, the data needed to apply this method may not be readily available. The agency's final report has been distributed to all state highway agencies. The report is summarized in NCHRP Research Results Digest 246.