Skip to content

Prevent congestion using dynamic speed limits

During the past decades, the number of cars on the road and the need for transportation has increased rapidly. Those increasing traffic volumes lead to an increase of congestion, reduced safety and an increase in pollution. Recent numbers show that there has been an increase of 16% between 2000 and 2012 in the amount of traffic on Dutch roads. It is expected that this growth continues will continue. The costs of congestion and delays are estimated to be between 1.8 and 2.4 billion euro per year. The easiest way to increase road capacity is to build more roads, which has been done extensively during the first half of the 20th century. A combination of an increased environmental concern and limited financial and physical resources however has led to a policy in which the current infrastructure should be used more efficiently.

In recent years, a number of studies on increasing the efficiency of existing roads have been performed. The results are promising but a lot of additional research is still needed in order to further improve the efficiency of the roads. One of the main issues caused by congestion is something called the capacity drop. Because the queue discharge rate is in general lower than the capacity of a road, the capacity of the road is not fully used. In current research, a lot of attention is aimed at resolving congestion when it occurs. The main issue with this approach is that when congestion sets in, the capacity drop will always be present. The main focus of this research is on improving the performance of a road by investigating a way to prevent congestion using dynamic speed limits. 

Start date: April 8, 2014
End date: May 11, 2015

Research topic:
Traffic management

Research question:
Speed limits and their effects