Explaining journey time loss and reliability on the main road network from 2000 to 2010. Empirical study of reliability aspects (English summary)

This report is available in Dutch.

Until 2000, the yearly change of time loss due to traffic jams and delays on the main road network was approximately equal to the yearly change of total traffic volumes, but in subsequent years time loss has become more difficult to predict.The development of journey time unreliability – that is, the extent to which a journey is longer than expected – largely corresponds to that of journey time loss. One aspect of journey time unreliability is a direct consequence of extreme journey times. The main road network therefore remains insufficiently robust for handling consequences stemming from incidents and exceptions that impact the total volume of traffic. Journey time loss due to extreme journey times increased less sharply than the overall unreliability levels.

These are some of the conclusions of research focused on developments in and explanations for reliability on the main road network in the Netherlands. The objective of this study was to use empirical research to provide insight into the developments in and explanations for reliability on the main road network from the perspective of car drivers. KiM Netherlands Institute for Transport Policy Analysis conducted this study on behalf of the Directorate-General for Reliability of the Ministry of Infrastructure and the Environment. Some of this study’s findings were previously published as part of the Mobility Report 2011, a document which provides a complete overview and comprehensive elaboration of the detailed developments in and explanations for reliability on the main road network.