THIS PAPER IS CONCERNED WITH THE ECONOMICS OF SEPARATE FACILITIES (ROADS OR LANES WITHIN ROADS) FOR AUTOMOBILES AND BUSES IN CONGESTED URBAN AREAS. IT SHOWS THAT ASSIGNING SEPARATE FACILITIES MAY BE OPTIMUM BOTH WHEN A CONGESTION TOLL IS CHARGED TO AUTOMOBILE DRIVERS ('FIRST BEST') AND WHEN NO SUCH TOLL IS CHARGED ('SECOND BEST'). THIS PAPER IS BASED EXCLUSIVELY ON DIFFERENCES IN THE CHARACTERISTICS OF MODES. TWO MAIN DIFFERENCES BETWEEN MODES ARE DISTINGUISHED. (1) MODES DIFFER IN THE CONTRIBUTION OF A PASSENGER TRIP TO CONGESTION; (2) THEY DIFFER IN THE EFFECT OF CONGESTION ON COST, DEFINED AS AVERSION TO CONGESTION. THE PAPER ELABORATES ON THE ROLE OF THESE TWO KINDS OF DIFFERENCES BETWEEN MODES IN JUSTIFYING SEPARATION OF FACILITIES. A COMPARISON IS MADE BETWEEN THE CHARACTERISTICS OF THE ALLOCATIONS UNDER COMMON AND SEPARATE USE OF TRANSPORT FACILITIES, AND BETWEEN FIRST AND SECOND-BEST FOR EACH REGIME. FINALLY, THE QUESTION OF A SECOND-BEST OPTIMUM POLICY OF BUSES IS EXAMINED. THE ANALYSIS IMPLIES THAT UNDER A REGIME OF SEPARATE FACILITIES IT IS LESS LIKELY (RELATIVE TO THE COMMON USE OF FACILITIES EXTENSIVELY ANALYSED IN LITERATURE) THAT THE BUSES SHOULD BE SUBSIDISED. DETAILS ARE GIVEN OF THE MODEL USED IN THE STUDY.
Abstract