Investigating traffic congestion in Shanghai: a system dynamics approach

Road congestion happens when road demand exceeds road supply. Therefore, people deem that constructing new roads – increasing the supply – can solve the problem. Shanghai has invested heavily in road construction since 1990s. Consequently, road congestion in Shanghai has been relieved. However, road supply can also stimulate road demand. Mainly, private cars will be more frequently used. This feedback was ignored before due to low personal income. Nowadays, with the fast economic development, an increasing amount of people can afford a car. Hence, it is necessary to consider this feedback when investigating the traffic problem. The system dynamics model developed in this study shows that road congestion will become more severe in the future if only increasing road supply. This result suggests that alternative policies, such as promoting public transportation should be emphasised. © 2006 Inderscience Enterprises Ltd.