WHY STANDARD MODELLING AND EVALUATION PROCEDURES ARE INADEQUATE FOR ASSESSING TRAFFIC CONGESTION MEASURES

As traffic congestion in Hong Kong worsens with the growing use of motor vehicles, to determine what has to be done to achieve and maintain an acceptable level of mobility for persons and goods becomes the subject of intense debate by economists, planners and politicians. Although many traffic congestion measures have been suggested and investigated, they are mainly confined to expansion of transport infrastructure and measures to make effective use of roads. New roads and public transport improvements may encourage increases in traffic and changes in the patterns of trips, while traffic management and regulation measures may in turn lead to suppression in road traffic. In order to evaluate these measures, it is required to make use of a transport model in assessing their traffic impacts. However, there are always discrepancies between the traffic forecasts and the actual flows on the roads. This paper investigates why the standard modelling and evaluation procedures currently used by the Hong Kong Government are inadequate for assessing the traffic congestion measures. Empirical evidence is given together with discussion on modelling and evaluation issues raised by the existence of suppressed/induced traffic.

[1]  Dietrich Braess,et al.  On the Existence of Equilibria in Asymmetrical Multiclass-User Transportation Networks , 1979 .

[2]  S. Erlander.  ACCESSIBILITY, ENTROPY AND THE DISRUPTION AND ASSIGNMENT OF TRAFFIC , 1977 .

[3]  H. Williams.  On the Formation of Travel Demand Models and Economic Evaluation Measures of User Benefit , 1977 .

[4]  Larry J. LeBlanc,et al.  Methods for Combining Modal Split and Equilibrium Assignment Models , 1979 .

[5]  David E. Boyce,et al.  Urban Transportation Network-Equilibrium and Design Models: Recent Achievements and Future Prospects , 1984 .

[6]  Haijun Huang,et al.  A combined trip distribution and assignment model for multiple user classes , 1992 .

[7]  W H Scheltes,et al.  EQUILIBRIUM TRAFFIC ASSIGNMENT WITH MULTIPLE USER CLASSES , 1986 .

[8]  J. A. Tomlin,et al.  A Mathematical Programming Model for the Combined Distribution-Assignment of Traffic , 1971 .

[9]  Sang Nguyen,et al.  Solution Algorithms for Network Equilibrium Models with Asymmetric User Costs , 1982 .

[10]  Tore Langmyhr,et al.  Managing equity: The case of road pricing , 1997 .

[11]  Hai-Jun Huang,et al.  Calibration of the combined trip distribution and assignment model for multiple user classes , 1992 .

[12]  M. Florian,et al.  A combined trip distribution modal split and trip assignment model , 1978 .

[13]  Carlos F. Daganzo,et al.  Computation of Equilibrium Over Transportation Networks: The Case of Disaggregate Demand Models , 1980 .

[14]  Larry J. LeBlanc,et al.  COMBINED MODE SPLIT-ASSIGNMENT AND DISTRIBUTION-MODEL SPLIT-ASSIGNMENT MODELS WITH MULTIPLE GROUPS OF TRAVELERS , 1982 .

[15]  Terry L. Friesz.  An equivalent optimization problem for combined multiclass distribution, assignment and modal split which obviates symmetry restrictions , 1981 .

[16]  Larry J. LeBlanc,et al.  Efficient Algorithms for Solving Elastic Demand Traffic Assignment Problems and Mode Split-Assignment Problems , 1981 .

[17]  M. Florian.  A Traffic Equilibrium Model of Travel by Car and Public Transit Modes , 1977 .

[18]  Sang Nguyen,et al.  On the Combined Distribution-Assignment of Traffic , 1975 .

[19]  Suzanne P. Evans,et al.  DERIVATION AND ANALYSIS OF SOME MODELS FOR COMBINING TRIP DISTRIBUTION AND ASSIGNMENT , 1976 .