25-06-2013, 12:00 PM
The Effectiveness of Speed Cameras
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Executive Summary
Background
Speed cameras were first used for enforcement in Great Britain in 1992, having
been recommended by a review of road traffic law in 1988. Their rollout was
accelerated between 2001 and 2005 in a national safety camera programme
under the ‘safer speeds’ theme of the road safety strategy 2000–2010.
Speed camera partnerships – joint ventures between police forces, highway
authorities and magistrates’ courts – were formed to implement this, and have
since taken on a wider role as road safety partnerships.
Sources of information
This report pulls together a range of analyses of the effectiveness of
speed cameras, and some more recent data, to provide a considered and
comprehensive assessment of their contribution to road safety. The sources
of information include the four-year camera evaluation report published
in December 2005; related work by Mountain, Hirst and Maher; studies in
London; national statistics on traffic speeds, collisions and casualties, and
international research on relationships between them; and recent figures
from road safety partnerships.
Changes in speed
The four-year evaluation report mentioned above looked at 2,000 sites (urban
and rural, using fixed and mobile cameras) where speed measurements were
taken both before and after camera deployment. Analysis showed that once
the cameras were operational, there was:
• a substantial improvement in compliance with speed limits;
• a particular reduction in extreme speeding;
• a marked reduction in average speed at fixed sites; and
• an appreciable, though more modest, reduction at mobile sites.
Casualty reduction at speed camera sites
But these changes in speed are not an end in themselves. The laws of motion
imply that lower speeds just before and at the instant of collision are associated
with more time for the driver to take avoiding or mitigating action, lesser exchange
of energy and momentum during the collision, and consequently lower forces
imposed on the bodies of people involved, resulting in lower severities of injury.
The key findings of this report
• Deployment of speed cameras leads to appreciable reductions in speed
in the vicinity of the cameras, and substantial reductions in collisions and
casualties at those locations over and above that which is attributable to
regression to the mean effects.
• Percentage reductions in collisions and casualties differ between fixed
and mobile, and between urban and rural camera sites. Judging from the
evidence, the operation of cameras at over 4,000 sites of all types resulted
in around 1,000 fewer people being killed or seriously injured in the vicinity
of cameras in the year ending March 2004.
• National surveys indicate clear and sustained falls in the average speeds
of cars on 30 miles/h roads, and in the proportion of cars exceeding the
limit, which are likely to have contributed to concurrent reductions in
collisions and casualties on built-up roads.
The need for speed management
Speed gets people and goods to their destinations sooner, but at a cost,
especially in terms of death, injury and damage in collisions, and in the
emission of carbon dioxide ( CO 2 ). Prevailing speeds stem from the choices
that drivers and motorcyclists make on each stretch of road as they find it. As
drivers, we see ourselves as gaining immediately from higher speed through
earlier arrival, and possibly the pleasure of going faster. We do bear some of the
cost ourselves (mainly increased running costs and personal risk), but we tend
to underperceive these costs. And in most cases we do not ourselves bear any
of the human costs to others of collisions, or much of the resulting damage to
the environment. For these reasons, it is inherent in the road traffic system that
many of us tend to go somewhat faster than is good for ourselves or society.
It would thus be wrong for each of us to be free to choose how fast to
drive. Responsible government rightly seeks to manage speed, usually by
moderating it. This does not just mean reining in a less responsible minority
of blatant speeders; it requires all of us who drive to do our bit – even if we
are tempted to think of ourselves as very responsible citizens. Most of us are
liable to go faster than is appropriate to the circumstances, and the ultimate
aim of speed management is to achieve appropriate speeds by all drivers and
motorcyclists everywhere.
Information, attitudes and enforcement
The need for public understanding of speed limits is one of the key issues
addressed by the national publicity campaign THINK! from the Department
for Transport (DfT), and an example of its achievements is that the proportion
of motorists regarding it as unacceptable or highly unacceptable to drive
at 40 miles/h where the limit is 30 miles/h rose from 60% in 1998 to 76%
in 2003 (DfT, 2006b). The work of THINK! both supports and is augmented
and complemented by the education, training and publicity activities of local
road safety partnerships, including speed awareness courses, and of other
organisations concerned for road safety.
The need for speed limits to be perceived as reasonable requires them to be
set with care and kept under review, especially in the light of changing traffic
conditions and public expectations concerning the safety of various kinds of
road user. These needs have been addressed during the years of widespread
use of speed cameras by a wide-ranging public consultation between
November 2004 and February 2005, followed by the issue in August 2006
of fresh guidance to local highway authorities on the setting of local speed
limits (DfT, 2006a). Since then, these authorities have been proceeding with
systematic reviews of speed limits on their roads.
[attachment=55955]
Executive Summary
Background
Speed cameras were first used for enforcement in Great Britain in 1992, having
been recommended by a review of road traffic law in 1988. Their rollout was
accelerated between 2001 and 2005 in a national safety camera programme
under the ‘safer speeds’ theme of the road safety strategy 2000–2010.
Speed camera partnerships – joint ventures between police forces, highway
authorities and magistrates’ courts – were formed to implement this, and have
since taken on a wider role as road safety partnerships.
Sources of information
This report pulls together a range of analyses of the effectiveness of
speed cameras, and some more recent data, to provide a considered and
comprehensive assessment of their contribution to road safety. The sources
of information include the four-year camera evaluation report published
in December 2005; related work by Mountain, Hirst and Maher; studies in
London; national statistics on traffic speeds, collisions and casualties, and
international research on relationships between them; and recent figures
from road safety partnerships.
Changes in speed
The four-year evaluation report mentioned above looked at 2,000 sites (urban
and rural, using fixed and mobile cameras) where speed measurements were
taken both before and after camera deployment. Analysis showed that once
the cameras were operational, there was:
• a substantial improvement in compliance with speed limits;
• a particular reduction in extreme speeding;
• a marked reduction in average speed at fixed sites; and
• an appreciable, though more modest, reduction at mobile sites.
Casualty reduction at speed camera sites
But these changes in speed are not an end in themselves. The laws of motion
imply that lower speeds just before and at the instant of collision are associated
with more time for the driver to take avoiding or mitigating action, lesser exchange
of energy and momentum during the collision, and consequently lower forces
imposed on the bodies of people involved, resulting in lower severities of injury.
The key findings of this report
• Deployment of speed cameras leads to appreciable reductions in speed
in the vicinity of the cameras, and substantial reductions in collisions and
casualties at those locations over and above that which is attributable to
regression to the mean effects.
• Percentage reductions in collisions and casualties differ between fixed
and mobile, and between urban and rural camera sites. Judging from the
evidence, the operation of cameras at over 4,000 sites of all types resulted
in around 1,000 fewer people being killed or seriously injured in the vicinity
of cameras in the year ending March 2004.
• National surveys indicate clear and sustained falls in the average speeds
of cars on 30 miles/h roads, and in the proportion of cars exceeding the
limit, which are likely to have contributed to concurrent reductions in
collisions and casualties on built-up roads.
The need for speed management
Speed gets people and goods to their destinations sooner, but at a cost,
especially in terms of death, injury and damage in collisions, and in the
emission of carbon dioxide ( CO 2 ). Prevailing speeds stem from the choices
that drivers and motorcyclists make on each stretch of road as they find it. As
drivers, we see ourselves as gaining immediately from higher speed through
earlier arrival, and possibly the pleasure of going faster. We do bear some of the
cost ourselves (mainly increased running costs and personal risk), but we tend
to underperceive these costs. And in most cases we do not ourselves bear any
of the human costs to others of collisions, or much of the resulting damage to
the environment. For these reasons, it is inherent in the road traffic system that
many of us tend to go somewhat faster than is good for ourselves or society.
It would thus be wrong for each of us to be free to choose how fast to
drive. Responsible government rightly seeks to manage speed, usually by
moderating it. This does not just mean reining in a less responsible minority
of blatant speeders; it requires all of us who drive to do our bit – even if we
are tempted to think of ourselves as very responsible citizens. Most of us are
liable to go faster than is appropriate to the circumstances, and the ultimate
aim of speed management is to achieve appropriate speeds by all drivers and
motorcyclists everywhere.
Information, attitudes and enforcement
The need for public understanding of speed limits is one of the key issues
addressed by the national publicity campaign THINK! from the Department
for Transport (DfT), and an example of its achievements is that the proportion
of motorists regarding it as unacceptable or highly unacceptable to drive
at 40 miles/h where the limit is 30 miles/h rose from 60% in 1998 to 76%
in 2003 (DfT, 2006b). The work of THINK! both supports and is augmented
and complemented by the education, training and publicity activities of local
road safety partnerships, including speed awareness courses, and of other
organisations concerned for road safety.
The need for speed limits to be perceived as reasonable requires them to be
set with care and kept under review, especially in the light of changing traffic
conditions and public expectations concerning the safety of various kinds of
road user. These needs have been addressed during the years of widespread
use of speed cameras by a wide-ranging public consultation between
November 2004 and February 2005, followed by the issue in August 2006
of fresh guidance to local highway authorities on the setting of local speed
limits (DfT, 2006a). Since then, these authorities have been proceeding with
systematic reviews of speed limits on their roads.