Wang_et_al_AAP_Final_submitted1.pdf (365.12 kB)
Impact of traffic congestion on road accidents: a spatial analysis of the M25 motorway in England
journal contribution
posted on 2009-09-15, 12:58 authored by Chao Wang, Mohammed Quddus, Stephen IsonTraffic congestion and road accidents are two external costs of transport and the reduction of their impacts
is often one of the primary objectives for transport policy makers. The relationship between traffic congestion
and road accidents however is not apparent and less studied. It is speculated that there may be
an inverse relationship between traffic congestion and road accidents, and as such this poses a potential
dilemma for transport policy makers. This study aims to explore the impact of traffic congestion on the
frequency of road accidents using a spatial analysis approach, while controlling for other relevant factors
that may affect road accidents. The M25 London orbital motorway, divided into 70 segments, was chosen
to conduct this study and relevant data on road accidents, traffic and road characteristics were collected.
A robust technique has been developed to map M25 accidents onto its segments. Since existing studies
have often used a proxy to measure the level of congestion, this study has employed a precise congestion
measurement. A series of Poisson based non-spatial (such as Poisson-lognormal and Poisson-gamma) and
spatial (Poisson-lognormal with conditional autoregressive priors) models have been used to account for
the effects of both heterogeneity and spatial correlation.
The results suggest that traffic congestion has little or no impact on the frequency of road accidents on
the M25 motorway. All other relevant factors have provided results consistent with existing studies.
History
School
- Architecture, Building and Civil Engineering
Published in
Accident Analysis & PreventionVolume
41Issue
4Pages
798 - 808Citation
WANG, C., QUDDUS, M.A. and ISON, S.G., 2009. Impact of traffic congestion on road accidents: a spatial analysis of the M25 motorway in England. Accident Analysis and Prevention, 41 (4), pp. 798-808Publisher
© ElsevierVersion
- AM (Accepted Manuscript)
Acceptance date
2009-04-12Publication date
2009-05-03Notes
This was published in the journal, Accident Analysis and Prevention [© Elsevier]. It is also available at: http://dx.doi.org/10.1016/j.aap.2009.04.002ISSN
0001-4575Publisher version
Language
- en