Memorandum by the Health Development Agency
(RTS 153)
THE IMPACT OF TRANSPORT AND ROAD TRAFFIC
SPEED ON HEALTH
1. INTRODUCTION
This briefing from the Health Development Agency
(HDA) begins by looking at the impact of transport on health—accidents,
physical activity and social interaction/quality of life—and
considers what part speed plays. It also considers the implications
for health inequalities. It then looks at the evidence of effectiveness
of interventions. Finally, it highlights some common elements
of approaches that have made progress in tackling the health impacts
of transport and speed.
2. KEY POINTS
Road traffic speed has a direct impact on health:
it is a major cause of crashes, and the seriousness of accidents
is related to speed.
Speed has important indirect impacts on health:
— Perception of road danger discourages
walking and cycling, two of the most important kinds of physical
activity.
— This perception restricts social
interactions (for example, by cutting people off from everyday
facilities), affects the quality of life, and can induce feelings
of stress, particularly among older people.
Speeding is more common in less affluent areas.
(There is a link between level of deprivation and child accident
rates.)
There is evidence that the following measures
can reduce road traffic speed:
— Engineering changes to the built
environment designed to reduce speed and calm traffic: 20 mph
zones seem to be particularly effective in achieving injury reductions.
— Safer routes to school schemes, which
can be effective in encouraging both walking and cycling.
— Targeting high-risk behaviours, particularly
speeding and drinking, by combining public education, engineering
changes and enforcement.
— Comprehensive local approaches to
speed management that put pedestrians, people and mobility problems
and cyclists at the top of the hierarchy of road users.
Local strategic partnerships (LSPs) should lead
comprehensive approaches, bringing partners together and linking
health improvement and modernisation plans (HIMPs), local transport
plans and community strategies.
Also essential is joint action at Government
Office level where public health teams should work closely with
regional transport and planning officers.
3. THE IMPACT
OF TRANSPORT
ON HEALTH
Three health impacts are significant in looking
at transport and speed: casualties, reduced opportunities for
physical activity and restriction of social interaction/quality
of life. These are discussed briefly below.
3.1 Casualties
The most visible heath impact of traffic speed
is road casualties. In 2000, there were 320,283 casualties and
3,409 people killed in motor vehicle traffic accidents in Great
Britain (DTLR 2001). This includes 42,033 pedestrian and 20,612
cyclist casualties and 857 and 127 pedestrian and cyclist deaths
respectively. Beyond these, there is an uncertain level of ill
health associated with the psychological effects of road crashes.
A study estimated that of all those treated in a casualty department
as a result of a traffic crash a third suffered from psychological
consequences and 45 per cent reported major physical problems
a year after the event (Mayou & Bryant 2001). The majority
(61 per cent) of physical injuries were minor.
It is generally accepted that speed is a major
factor in road crashes, and particularly on the severity of the
outcome (DETR 1999). Excessive and inappropriate speed is the
major contributory factor in around a third of all road accidents
(Carsten et al 1989). A review of the literature on the
relationship between speed and accidents (Finch et al 1994)
found a reduction in accidents of around 5 per cent for each 1
mph speed reduction.
There is a dramatic variation in road casualties
across socio-economic groups. The pedestrian death rate for children
from families in social class V is five times that for those from
social class I (Roberts & Power 1996), and there is a correlation
between the level of deprivation of an area and child accident
rates (Kendrick 1993). Speeding is more common in less affluent
areas (MacGibbon 1999). The Acheson report (Acheson 1998) noted
that there would be 600 fewer deaths annually among men aged 20-64
if all groups experienced death rates from motor vehicle traffic
accidents now seen in social classes I and II combined (Acheson
1998).
3.2 Reduced opportunities for physical activity
Physical inactivity is accepted to be a major
risk factor for a range of health outcomes, including coronary
heart disease, colon cancer, diabetes and overweight/obesity.
The prevalence of inactivity in the population is substantial,
with around 60 per cent of men and 70 per cent of women failing
to reach the minimum recommendation of 30 minutes moderate activity
at least five times a week. In population terms this means that
inactivity has a significant impact. For instance, it is estimated
that the population attributable risk of coronary heart disease
from inactivity is 37 per cent (British Heart Foundation health
promotion research group 2002). The British Heart Foundation estimates
costs to the health care system from coronary heart disease of
around £1,600 million (British Heart Foundation health promotion
research group 2002) and the National Audit Office estimates direct
costs of treating the outcomes of obesity as at least £0.5
billion a year (NAO 2001).
The current advice on minimum levels of physical
activity is for all adults to take at least 30 minutes of moderate
activity on at least five days of the week. Incorporating activity
into the normal routines of daily life is likely to be the most
effective way of achieving this. Cycling and walking are examples
of suitable moderately vigorous activities that have the potential
to be included in daily activities.
Independent travel by children, particularly
to school, has declined dramatically over recent years. The percentage
of primary school children walking to school has declined from
67 per cent to 53 per cent between 1985-86 and 1996-97, with a
corresponding rise in those travelling by car from 22 per cent
to 38 per cent. Cycling to secondary school has declined from
6 per cent to 2 per cent (DTLR 2002).
The major deterrent to cycling expressed by
non-cyclists is fear of motor traffic (Carnall 2000). Vehicle
speed is a major factor in perceptions of the road environment
as hostile by both cyclists and pedestrians.
There is evidence of "suppressed demand"
for cycling and walking. A survey by MORI for the Commission for
Integrated Transport (CfIT 2001) found that 47 per cent of people
said they would cycle more and 65 per cent would walk more if
problems were addressed. Safety was a key issue in both groups:
32 per cent of cyclists identified better/safer cycling routes
as a solution (the most common response) and 26 per cent of pedestrians
identified safe walking routes (the most common response being
fewer cracked pavements—32 per cent). Average distance travelled
per year by foot has declined over recent years, from 244 miles
in 1985-86 to 191 miles in 1997-99—a drop of 22 per cent
(DTLR 2002).
Physical activity levels vary with social class.
However, the relationship is not straightforward. Overall, men
in lower social classes tend to be more active than those in higher
social classes, partly due to the effect of activity at work.
There is no clear pattern by social class in women. Deprived groups,
however, are twice as likely to be sedentary as the most
affluent. The built environment, including road traffic density
and speed, is a major influence on the quality of the experience
of walking in urban environments (Bostock 2001)—an experience
which can be stressful, potentially adding to the burden of ill
health of those living in degraded environments. Increasingly,
there is an acceptance that environmental considerations influence
the level of physical activity (Brownson et al 2001; Sallis
et al 1997).
3.3 Restriction of social interaction/quality
of life
Severance, whereby motor traffic reduces access
to health promoting facilities for those on foot or travelling
by bicycle, has important health effects. Access to a healthy
diet, places for activity, employment and recreation can be restricted
and feelings of insecurity, anxiety and stress increased, particularly
among older people (Health Education Authority 2000). Traffic
volume and speed influence the level of non-traffic activity on
streets—for equivalent streets, the higher the volume of
traffic the lower the pedestrian activity (Appleyard 1981). Perception
of road danger is one of the key reasons for this decline. Traffic
speed is frequently identified as a major concern in public consultations.
For instance, 68 per cent of people in a consultation for Gloucester
Safer City identified speeding as a concern (Gloucester Safer
City 1998). In a MORI poll for the Local Government Association
road safety/traffic speed was the most commonly cited aspect of
the local neighbourhood in need of improving: road safety/traffic
speed and facilities for young people/children were both cited
by 30 per cent of respondents (http://www.mori.com/polls/1999/lga0699.shtml).
4. EVIDENCE OF
EFFECTIVENESS OF
INTERVENTIONS
The HDA review of effectiveness of interventions
in preventing unintentional injury in children and adolescents
(Towner et al 2001) looked at interventions in a number
of different environments. In the road environment, the authors
looked at general interventions, and those aimed at pedestrians,
cyclists, car passengers and bus passengers. They found reasonable
evidence for the effectiveness of area-wide engineering measures
and good evidence for the effectiveness of 20 mph zones in achieving
injury reductions. The evaluation of 20 mph zones (Webster &
Mackie 1996) found reductions in accidents of about 60 per cent
and vehicle speeds by over 9 mph. Public acceptability surveys
of residents were generally in favour of the schemes. Child pedestrian
injuries were reduced by around 70 per cent and child cyclist
injuries by 48 per cent.
It is possible to increase levels of physical
activity, and of walking in particular. The HDA guidance on prevention
of coronary heart disease (Health Development Agency 2000a) and
the forthcoming guidance on cancer prevention (Health Development
Agency 2002) look at how physical activity can be encouraged.
Characteristics of activities that have been found to encourage
uptake are those that are easily included into an existing lifestyle,
are enjoyable and do not depend on attendance at a facility. Walking
is the exercise most likely to fulfil these criteria (Hilsdon
et al 1995). The US Centers for Disease Control and Prevention
report on community based physical activity (Centers for Disease
Control and Prevention 2001) found sufficient evidence to recommend
development of walking trails as an effective intervention. Promotion
of cycling and walking to work or to school can also be effective.
Safer routes to school, as part of school travel plans, frequently
include measures to reduce motor traffic speed and provide space
for other modes. These programmes can increase both cycling and
walking to school. For instance:
— An increase of 30 per cent in walking
to school following the introduction of walking buses in St Albans.
Walking buses generally comprise two volunteer parents, one to
"drive" and one to "conduct", a trolley to
carry school bags, and a long line of children.
— 61 per cent of children cycling to
Kesgrave school (Suffolk) following development of safer walking
and cycling routes. (School Travel Advisory Group 2000).
Integrated interventions have been shown to
be effective. Between 1989 and 1995 the State of Victoria in Australia
identified a growing road death problem with deaths increasing
at 5 per cent per month. The Victoria Solution, renamed Safety
First (PACTS 1998) concentrated on high-risk behaviours, particularly
speeding and alcohol. The strategy used a combination of education,
engineering and enforcement (with evaluation added). Automated
radar speed cameras checked two million drivers each month, and
speeding was reduced from 23 per cent to a current rate of under
2 per cent. Evaluation identified:
— 52 per cent reduction in road deaths.
— 36 per cent reduction in serious
injuries.
— 22 per cent reduction in reported
crashes.
— Over 100,000 hospital beds freed.
— Direct savings of over AU$980 million
to TAC (Transport Accident Commission—the state monopoly
third party insurer).
The parties involved emphasise that "road
safety is not something that the authorities DO to a community,
it is something that a community does for itself in association
with the authorities". Community involvement is necessary
if hard-hitting advertising backed by effective technology-based
traffic law enforcement is to be accepted and to make speeding
and drink driving socially unacceptable.
The Gloucester Safer City project was a city-wide
demonstration project running from April 1996 to March 2001 (Gloucester
Safer City 1998). Based on a comprehensive approach to speed management
with the following key ingredients: working within the framework
set by Gloucestershire's Sustainable Transport Plan; extensive
education and awareness campaigning, consultation and partnership;
analysis of traffic flows and speeds, crash casualty records for
the entire city and existing land uses; and a new road hierarchy
for the city. Work included area-wide traffic calming on mixed
use and residential roads and high profile enforcement of speed
limits. By July 1999 achievements included: 47 per cent reduction
in personal injury casualties; 5 mph reduction in speed on treated
main roads and 10 mph reduction on mixed use and residential roads;
15 per cent reduction in motor traffic on mixed use and residential
roads; modal shift in journeys to work through cycling and use
of public transport (including an element of walking): 60 per
cent of those surveyed feeling safer than they did five years
previously.
In Germany a programme of establishing 30 kph
zones has been shown to be effective in reducing speeds. In Buxtehude,
one of the demonstration projects, establishment of 30 kph zones
and a five-tier road hierarchy (pedestrian zones, residential
streets, collector streets, main roads and limited access roads)
has reduced traffic speed on all types of road. At the same time
levels of pedestrian and cycle traffic have increased by 17 per
cent and 27 per cent respectively (Davis 2001).
The City of York has adopted a comprehensive
transport policy based on a "hierarchy of road users".
This priority list is applied in making and implementing land
use and transport-related decisions and measures. The list is
as follows (in order of priority):
— People with mobility problems
— Public transport users, including
taxis
— Commercial/business users
— Car-borne commuters and visitors.
It takes a danger reduction approach to speed
management that has helped it meet national casualty reduction
targets well in advance of target dates. The Council recognises
that "slowing traffic down is the best way to stop accidents
and make the roads feel safer for all road users". Three
road categories with target speeds and measures to achieve compliance
have been defined. These are traffic routes, mixed priority routes
and residential areas. The target speed in the last category is
20 mph.
Walking is an important form of transport in
York with 24 per cent (double the national average) of journeys
to work made on foot. The City Council adopted a Pedestrian Strategy
in 1992 to promote and encourage more walking. This identified
a 120 km route network, which will be improved to provide a safer
and more pleasant pedestrian environment.
Cycling is also an important form of transport
in York. 20 per cent of journeys to work are made by bicycle.
The national average is less than a quarter of this. A Cycle Strategy
identified 80 km of cycle route of which about half has now been
implemented. Advanced stop lines and signalised crossings are
being installed to make cycling safer, and already there has been
a reduction of 28 per cent in the number of cycle accidents, in
the context of an increase in cyclist and walkers—against
the national trend.
5. THE FUTURE
Many of the interventions required to address
the adverse impacts of speed are outside the direct control of
the Department of Health and the NHS. However, evidence of successful
action in transport and health has shown the benefit of combined
action to achieve joint or overlapping goals.
The Social Exclusion Unit (SEU) is currently
examining transport and social exclusion and is considering proposals
for targeted action to reduce child pedestrian injuries in deprived
areas. If introduced, these could focus on speed and ensure all
local agencies work together to address this issue.
A number of elements seem to be common in achieving
progress in tackling the health impacts of transport and speed.
These are:
— Adopt a comprehensive approach as
part of broader neighbourhood renewal strategies and community
strategies. Effective policies tend not to focus on single problem
sites or issues but try to address broader problems. Similarly,
they are not restricted to single professional groups but include
partners from across professions as well as engaging with the
community.
— Joint action at regional level is
key, with Government Offices' new public health teams working
closely with regional transport and planning officers.
— There is a role for health professionals
to act as "champions" for the health benefits of changes
in transport policy and activity locally and to support the development
of local information systems to identify and provide the necessary
intelligence to support action (such as the road accident database
developed in Cambridge). Such systems would include linking data
between local government, police and health services to inform
action on accidents; undertaking community health needs assessment
in relation to physical activity, safety and access; and developing
health impact assessment of transport policy.
— Changes in the built environment
(such as traffic calming) are likely to be significant but are
not the only element of effective schemes. The Victoria experience
emphasised the importance of education and enforcement as well
as environmental changes, combined with ensuring community "buy-in"
to the proposed interventions. This requires joint work across
local services, led by the local strategic partnership (LSP).
Health improvement and modernisation plans (HIMPs) need to link
to local transport plans, set out a joint approach and feed into
the community strategy.
— Specific projects (such as workplace
travel plans) to promote physical activity through transport can
be effective. These will be more effective if they include action
to address barriers such as perception of risk, the need to carry
and store bags and so on.
— Local practitioners frequently mention
that ensuring that guidance from different government departments
is integrated is a key element in facilitating local action.
— Local flexibilities—enhanced
by the Health Act (1999), the power of local authorities to promote
and improve well being and the production of local community strategies—provide
an ideal opportunity to develop comprehensive local action. Use
of joint funding and pooled budgets will be key to tackling issues
like speed. Some early examples (including funding of speed cameras)
are set out in the Appendix, and this type of work should be actively
encouraged.
— Local public service agreements (LPSAs)
could be a key lever, linking to Best Value and the NHS performance
framework. LSPs could identify joint targets.
Hugo Crombie is Public Health Adviser, Physical
Activity at the HDA.
REFERENCES
Acheson, D ed 1998, Independent inquiry into
inequalities in health, The Stationery Office, London.
Appleyard, D 1981, Livable streets, University
of California Press, Berkeley.
Bostock, L 2001, "Pathways of disadvantage?
Walking as a mode of transport among low-income mothers",
Health Soc Care Community, vol 9, no 1, pp 11-18.
British Heart Foundation health promotion research
group 2002, Coronary heart disease statistics, British
Heart Foundation, London.
Brownson, R C, Baker, E A, Housemann, R A, Brennan,
L K, & Bacak, S J 2001, "Environmental and policy determinants
of physical activity in the United States", American Journal
of Public Health, vol 91, no 12, pp 1995-2003.
Carnall, D 2000, "Cycling and health promotion.
A safer, slower urban road environment is the key", BMJ,
vol 320, no 7239, p 888.
Carsten, O J M, Tight, M R, Southwell, M T,
& Plows, B 1989, Urban accidents: Why do they happen? AA
Foundation for Road Safety Research, Basingstoke.
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