ALLOCATING HIGHWAY PROGRAM COSTS TO WASHINGTON STATE HIGHWAY USERS

This paper analyzes a Washington State highway cost-allocation study that determined road-user cost responsibilities for support of the state-aided highway program at both the state and local levels. The study used an incremental cost-allocation model for over 350 individual highway user subclasses correlated with vehicle type, use class, power type, and registered gross vehicle weight. Cost responsibilities for alternative funding programs were compared with user tax payments to assess equity performance. There is considerable variance among vehicle classes in the degree to which tax payments meet cost responsibility. The automobile consistently fails to meet its cost responsibility, trucks generally attain measures of equity comparable to that of the automobile, and intercity buses generate the lowest level of tax payment relative to cost responsibility. Equity performance among trucks varies with engine power type and use class; commercial-class and gasoline-powered trucks generally attain the highest equity levels. Cost responsibility for heavier vehicle sub-classes varies significantly with changes in budget composition. The proportion of the budget devoted to construction--and in particular to pavement--is a prime factor. The sensitivity of the results to allocation model variations and input data is also addressed. /Author/