Is Traffic Congestion Bad for Road Traffic Accidents? Spatiotemporal Analysis of United Kingdom Major Roads Using Spatial Econometrics

A spatio-temporal analysis has been conducted aiming to explore the relationship between traffic congestion and road accidents based on the data on the M25 motorway and its surrounding major roads in England during the period 2003 – 2007. It was hypothesized that increased traffic congestion may be beneficial to road safety as the number of fatal and serious injury accidents would be less due to low average speed when congestion is present. If this is confirmed then it poses a potential dilemma for transport policy makers. A series of classical count outcome models (random-effects Negative Binomial models) and spatial models using a full Bayesian hierarchical approach have been developed in this study in order to examine whether congestion has any effect on the frequency of accidents. Estimation results from the two types of model are generally consistent with each other, and the spatial models appear to be more appropriate in terms of model inference and the fact that spatial models can take into account spatial correlation. The results suggest that increased traffic congestion is associated with more fatal and serious injury accidents and traffic congestion has little impact on slight injury accidents. This may be due to the higher speed variance, acceleration and worse driving behavior in the presence of congestion. Other contributing factors have also been controlled for and produced the expected results.


  • English

Media Info

  • Media Type: DVD
  • Features: Maps; References; Tables;
  • Pagination: 19p
  • Monograph Title: TRB 89th Annual Meeting Compendium of Papers DVD

Subject/Index Terms

Filing Info

  • Accession Number: 01153441
  • Record Type: Publication
  • Report/Paper Numbers: 10-0617
  • Files: TRIS, TRB
  • Created Date: Jan 25 2010 10:18AM