Accident blackspot

An accident blackspot is a term used in road safety management to denote a place where road traffic accidents have historically been concentrated. It may have occurred for a variety of reasons, such as a sharp drop or corner in a straight road, so oncoming traffic is concealed, a hidden junction on a fast road, poor or concealed warning signs at a cross-roads.

For some decades treatment of accident blackspots (e.g. by signage, speed restrictions, improving sightlines, straightening bends, or speed cameras) was a mainstay of road safety policy, but current thinking has it that the benefits of these interventions are often overstated. Effects such as regression to the mean [UCL and PA consulting for Department for Transport [http://www.dft.gov.uk/pgr/roadsafety/speedmanagement/nscp/nscp/coll_thenationalsafetycameraprog/thenationalsafetycameraprogr4598 UK national safety camera programme - Four-year evaluation report December 2005] Appendix H describes the effects of RTM] ,
risk compensation [cite paper
title=A driving-simulator test of Wilde's risk homeostasis theory
author=Jackson JSH, Blackman R
date=1994
publisher=Journal of Applied Psychology] and accident migration combine to reduce the overall benefit.

In some cases it has been claimed that the end result is an "increase" in overall casualties.In one notable experiment, a number of accident blackspots were "treated" with a null treatment - placement of a garden gnome, according to some reports. Accident rates at these points were found to have decreased significantly in the following period, a finding which is taken as clear evidence supporting the theory of regression to the mean.

References

* [http://www.transport-links.org/transport_links/filearea/publications/1_578_PA1337_1994.pdf; Discussion of accident blackspots]

Footnotes