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.