Mitigation of expressway traffic congestion through transportation demand management with toll discount

The result of four transportation demand management (TDM) implementations in three major traffic concentration periods of 2007-2008 with discounts on tolls for electronic toll collection vehicles, as intended to mitigate traffic congestion in an uninterrupted flow section of the Tomei expressway is described. As a result of the TDM implementation, the peak-hour demand is estimated to decrease by 2-5-. Although traffic congestion continues to occur, partly because of the increased daily traffic demand and the insufficient shift of traffic demand from peak hours to off-peak hours, it is estimated that the total delay is reduced by 27-35- relative to the case in which there is no TDM implementation, resulting in a reduction in CO₂ emission of 6-8- and 65 ton-c for the four TDM implementations. It is seen that the average shift rate of traffic increases with the amount of the toll discount. Apparently, it is also difficult to expect a high shift rate of traffic if the amount of the discount is less than approximately 1000 yen. The estimated midpoint arc elasticity of the toll-discount time period ranges from -0.30 to -0.72, depending upon the holiday type and the details of the discount time period.