Ex-post Evaluation of National Policy Programmes On Traffic Congestion

Ex-post Evaluation of National Policy Programmes On Traffic Congestion


H Van der Loop, Ministry of Transport (AVV); J Perdock, MuConsult BV, NL



Public authorities are faced with demands of the society to give a better insight in the costs and outcomes of policy. Many countries plan and implement policy programmes to reduce congestion. But until now, empirical evaluation of the results of these plans at a national scale afterwards hasn?t been done.

Since 2002 in the Netherlands a new budget system has been introduced which demands

from national authorities to describe yearly the planned policy measures, the planned costs and the anticipated outcomes. Also every year has to be reported which policy measures have been realised, the costs made and the outcomes realised.
In the paper and presentation the results of ex-post evaluation of policy programmes to reduce congestion will be presented.

In the Netherlands, congestion on the main trunk road network is increasing for many years. To reduce congestion or at least avoid excessive growth of congestion many policy measures are planned and implemented. As a follow-up of the Second Structure Transport Plan a new long-term plan is being prepared this year called ?Nota Mobiliteit?. Recently a new Act has been adopted to implement a number of policy measures such as peak lanes (Spoedwet Wegverbreding). All policy programmes are characterised by a mix of measures intended to influence the demand of transport and the supply of the transport system. Examples of policy measures are: transport management, ?variabilisation? (compensation in vehicle tax for higher petrol taxes), improvements of public transport, extension of traffic management (e.g. by peak lanes) and new infrastructure mainly by adding more lanes. The question is how these measures did influence the development of congestion.

To carry out the evaluation, data were collected on the development of congestion, the implementation of policy measures and the development of external factors (population, economic development, employment, income, car ownership, spatial developments). Also, information was collected on specific project evaluations such as the evaluation of transport management by employers and traffic management by the national road authority. As a first step of analysis a conceptual model was developed hypothesising the relationships between the influencing and dependent variables. Further these relationships were tested and estimated by analysing the data.

In the paper and presentation the results and conclusions of the evaluation of policy measures available about the period 2000 until 2003 will be described. These results are planned to be available in May 2004. At this moment the results of the analysis in the period 1995 until 2000 are already available. The conclusions of the analysis of the period 1995 until 2000 on the main trunk network are: 1) The amount of effect of all policy measures on the number of hours lost by congestion was as high as predicted before (a reduction of about 45% of the number of hours (?vehicle hours of congestion?) in 1995). 2) The amount of vehicle hours lost by congestion in the period from 1995 until 2000 increased in stead of decreased (+ 20 % in stead of?25%). This was due to the higher increase of population and employment than predicted before. 3) Policy programmes aimed at influencing the demand had less effect than predicted before, because measures were not implemented as full as planned. Traffic management on the other hand was intensified and had more effect than planned before. Because the data are improved and the method further developed, the analysis in the period 2000 until 2003 will be more accurate than the analysis in the period 1995 until 2000.


Association for European Transport