Ex-post Evaluation of Policy Measures on Traffic Congestion
LOOP H VAN DER, Ministry of Transport (AVV), PERDOK J, MuConsult and SCHRIEK A VAN, Ministry of Transport (Directorate Utrecht), The Netherlands
In the Netherlands in 1990 a national policy plan directed at accessibility, safety and the environment, the Second Transport Structure Plan, was approved. As part of this plan a monitoring system has been developed (described in another paper at ETC 2000
In the Netherlands in 1990 a national policy plan directed at accessibility, safety and the environment, the Second Transport Structure Plan, was approved. As part of this plan a monitoring system has been developed (described in another paper at ETC 2000: ""To measure is to know": results of a system for monitoring transport policy in the Netherlands"). One specific objective of this monitoring system is the identification of the effects of the policy measures after the plan has been implemented (ex-post evaluation). This paper deals with the identification of the effects of policy measures on congestion on the Dutch trunk road network.
In the period from 1996 until 1999 a new method was developed in the Netherlands to identify the effects of a policy programme designed to reduce congestion on the Dutch trunk road network. Apart from measures aimed at increasing road capacity (e.g. extra peak lanes) and measures directed at traffic management, measures influencing travel demand were also planned. The problem was how to evaluate the effects of these measures (ex post). The problem was how to deal with the many influencing factors: policy measures as well as external factors (developments in population, socio-economic changes, geographical factors, etc.) which influence the use of the trunk road network during a period of several years.
A first step was to identify a conceptual explanatory framework, the next step was to collect data. Furthermore, a method was developed which could deal with the identification of the relations between the explanatory factors and congestion, the phenomenon which was expected to be influenced by policy measures. This method uses statistics concerning external developments (e.g. population, labour participation, geographical data, traffic congestion), results from ex-post project evaluation studies and data from experts on local development and circumstances.
The method consists of an integrated approach in which regression analyses, known elasticities and expert opinions are used to separate external developments from the policy effects.
In this paper, a description of the conceptual framework will firstly be given as a basis for measurement and analysis. Then the methodology as developed and the results of this study in the central urban area of the Netherlands (the province of Utrecht) will be presented. Finally, conclusions will be formulated.
Association for European Transport