A Study of Adjusted Optimal Congestion Pricing with Speed-Flow Relationship in the Urban Express Way in Korea

Congestion pricing scheme has been in operation since 1996 at Namsan tunnel in Seoul Korea. Although many people against with this project in the first implementation year, this project had proven to be effective in reducing the congestion problem in this area. However, it's price never been changed for 4 years and no one knows current toll is optimal or appropriated. So the Metropolis of Seoul government wants to increase in its fares, furthermore they considered the Electronic Toll Collect system (ETC). This paper will not only offer theoretical method in its application but also calculated an actual congestion toll that corresponds to travel speed. There are two kinds of congestion toll estimation method. First, the estimation of congestion toll by speed-flow relationships, which based on engineering method. Second, the exact knowledge on economic and behavioral factors, such as, the demand functions and the generalized travel costs. In this paper we suggest an actual congestion toll by speed-flow relationships, the generalized Drake model, which representative well this region. And we were applying speed-elasticity function of the flow by Michael Z.F.Li. To the conclusion, current congestion toll is too low, which equivalent to 50km/h speed. Up to now the speeds were, on average 28.9km/h in this region, therefore travelers paid more that the travel speed exceed over 50km/h and paid less during the peak hour.