HIA of Transport Initiatives a Guide - HS IOM Scotland - 2007

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Health Impact Assessmento Transport InitiativesA Guide

Health Impact Assessmento Transport InitiativesA Guide

HIA and Transport Interventions

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Health Impact Assessment o Transport Initiatives: A GuideHealth Impact Assessment o Transport Initiatives: A Guide

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About this guide

This guide has been written to help people doing a health impact assessment oa transport proposal. It:

provides some background inormation on transport in Scotland and the policy context

contains a review o literature evidence on transport and health suggests some questions to help apply literature ndings to the context o a specic proposal

outlines how to use the evidence to do a health impact assessment;

provides brie summaries o completed health impact assessments (HIAs) o transport-related topics

highlights sources o inormation and data about transport.

Scope o the literature reviewThis guide oers an overview o the best available research evidence on the health impacts (both positiveand negative) o transport initiatives. The ocus o the review is on transport or access rather than transportas a leisure pursuit in itsel (e.g. cycling or walking as a sport or leisure activity). a Thereore, this review doesnot include interventions to increase physical activity, unless through promoting walking and cycling as analternative to using motorised transport. The document includes only a very short summary o the healthimpacts o climate change.

Members o the editorial groupMargaret Douglas, Consultant in Public Health, Lothian NHS Board

Hilary Thomson, Senior Scientic Ocer, Medical Research Council Social and Public Health Sciences Unit

Ruth Jepson, Senior Research Fellow, Cancer Care Research Centre, University o Stirling

Fintan Hurley, Scientic Director, Institute o Occupational Medicine

Martin Higgins, Senior Public Health Researcher, Lothian NHS Board

Jill Muirie, Senior Public Health Adviser, Health Scotland

Dermot Gorman, Consultant in Public Health, Lothian NHS Board

Acknowledgements

We would like to express our thanks to Susan Handy, Salim Vohra, Fiona Bull and Heather Walton,who all reviewed the drat document and provided constructive comments. Responsibility or thenal document rests with the editorial group.

a Throughout this document the terms bicycle and cycling reers to pedal cycles as opposedto motorcycles, where the terms motorcycles and motorcycling are used specically.

Section 1: Background

Margaret Douglas, Jill Muirie and Martin Higgins

Chapter 01: Transport in ScotlandScotland is characterised by a ew large, built-up urban centres, a number o smaller towns, and vastremote and rural areas. Transport is thereore o great importance, particularly or those in remoteand rural areas that have ew, i any, local public transport services. The range o transport optionsavailable in Scotland includes aeroplane, erry, train, motor vehicle (car, bus, coach, motorcycles orpedal cycle), walking or a combination o these.

National Travel Survey results or 2002/03 ound that an average Scottish resident travelled around6670 miles per year within the UK and spent on average o just under one hour per day travelling.About 74% o the total distance travelled was by car. 1 The total distance travelled increased by 43%

between 2002/03 and 1985/86 and refects an increase in the distances people travel during each trip.The average length o a trip was 43% higher in 2002/03 than in 1975/76 but the average number otrips per person per year rose by only 12% in that time.

In 2003/04 the Scottish Household Survey2 ound that:

66.5% o Scottish households had one or more motor vehicles available or private use(i.e. 33.5% o households do not have a car available or private use)

22.7% o households had two or more cars

In commuting to workplaces in 2003/04:

63% usually travelled by car or van: 55% as driver, 8% as passenger

48% o these said they could use public transport

15% walked to work 14% travelled by bus

3% travelled by train

2% cycled to work

In travelling to school in 2003/04:

52% o pupils usually walked

23% travelled by bus

22% travelled by car/van

1% cycled

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Underlying these gures is considerable variation according to the area in which people live.For example, car ownership was greater in rural areas (82%) than large urban areas (57%).In Aberdeenshire 84% o households have access to at least one car, whereas in Glasgow

only 45% o households have access to a car. In 2003/04, 34% o households had one ormore bicycles.3

The survey highlights how important car use is or access to important acilities. In total, 87% opeople said they always use a car or supermarket shopping and 72% o people said they wouldnd supermarket shopping airly or very dicult without a car; 64% said they always use a carto visit their GP, 72% always use a car to visit riends and relatives, and 48% always use a car orleisure nights out. Overall, 54% said that they would nd it airly or very dicult to visit their GPwithout a car - this rose to 80% in remote rural areas but, even in large urban areas, 47% saidthey would nd it airly or very dicult to visit their GP without a car.

Public transport was described as very convenient by 51% o adults in large urban areas, butby only 19% o those living in remote rural areas. Just over one-hal (54%) o adults said thatthey had made a trip o more than a quarter o a mile by oot to go somewhere in the previousseven days.

Determinants o transport mode

Decisions around choosing to travel by car, public transport, bicycle or oot are complex and willoten take into account a number o actors. A report published in 2003 by the Scottish Executiveidentied the barriers preventing car travellers rom choosing to travel by rail, bus, oot or cycle, or notundertaking a journey at all.4 A summary o good and bad aspects o dierent modes o transportas perceived by residents in an afuent part o Glasgow is presented in Table 1. This illustrates theimbalance o many good perceptions o private car versus ew good perceptions o public transport.

The most important barriers to using public transport, walking or cycling were reported cost, time and

reliability. Other actors included lack o inormation about timetables and routes, comort, securityand a wide range o individual needs and attitudes. Complementary or liestyle actors that infuencetransport choice included non-transport costs and taxes, limited amount o travel time and the needto carry goods. Measures recommended to promote a modal shit rom car use to public transport,walking or cycling include improvements to alternative orms o transport - including improvinginormation and reliability, and ways to make car travel less attractive.4 (For more specic determinantso physically active transport see Chapter 4.)

Car Pollution

Congestion

Stress o driving - road rage,guilt about not using public transport

Speed cameras

Poor road maintenance and signage

Convenience

Fast

Comort

Personal saety

Carry loads/equipment

More economical or carowners to use car than payor alternative transport

Table 1: Perceptions o dierent modes o transport that may infuence choice o transport mode(summary o ndings rom residents in an afuent suburb o Glasgow).4

Public transport(general)

Inconvenience - times, location o stations/stops, bus and train routes not well integrated

Lack o comort - vehicles oten overcrowdedand vandalised, walking to station/bus stop

in bad weather is unattractivePersonal saety - stations/bus stops areoten unmanned

No worry about parking

Train High cost

Unreliable in poor weather

Fast

Environmentally riendly

Bus Unreliable

Lack o timetable inormation

Exact change or are required

Slow

Aected by congestion

Polluting

Low cost

Walking/cycling Danger

Exposed to pollution

Weather dependent

Not able to carry goods/equipment

Healthy/exercise

Low cost

Predictable

Environmentally riendly

Weather dependent

Not able to carry goods/equipment



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Chapter 02: Transport Policy Context

This chapter outlines recent transport policy in Scotland, and some o the infuenceson this area o policy.

Historical background

The rst transport strategies in the UK emerged in the 1940s. In the 1950s and 1960s, the mainemphasis was on constructing a road network. Motorways and trunk roads were established acrossEngland; the rst parts o the motorway network in Scotland were built in the mid-1960s. At aroundthe same time, the British rail network was substantially reduced in scope. The Beeching Reportidentied numerous unaordable, unused stations and branch lines that were subsequently closed. 5

The oil crisis o the mid-1970s caused large increases in petrol prices. Following this, the governmentbecame concerned about the costs o road transport and reduced the scope o road-buildingprogrammes. This change in policy was linked also to increasing awareness o the potential

environmental impacts o vehicle movement.

A change in government in 1979 brought a new emphasis in transport policy. During the 1980s, busservices were deregulated and plans to privatise British Rail began. Deregulation o the rail networkbegan in 1994 and was completed by 1997. Some major new roads were completed (most notablythe M25 around London and the M40 between London and Birmingham) and, amid an economicboom in the late 1980s and a relative reduction in uel prices, car numbers increased steadily. In 1989,National Road Trac Forecasts predicted a 142% growth in trac levels up to 2025. 6 This led to amajor road construction scheme known as the Roads or Prosperity scheme.7 Although road-buildingwas acknowledged to increase use and thereore congestion, it was argued that economic developmentwas dependent on vehicle movement.

Car ownership has increased rapidly since the 1950s and although uel prices have increased consistentlyin real terms (around 10% higher than 1980), the so-called real cost o motoring has steadily decreasedand is now lower than the 1980 level (includes purchase, maintenance, uel, tax and insurance). 8,9

Meanwhile, the cost o rail and bus transport has increased and is now 37% higher in real terms thanin 1980.9 Policy initiatives that seek to moderate vehicle movement were rst suggested in the SmeedReport in the 1960s.10 Yet, taxation aside, very ew preventive initiatives have been implemented. Roaduser charging in London and Durham, and bus lanes with punitive measures or other vehicles enteringthem, are recent developments.

Use o rail travel declined rom a peak in 1964 to a low in 1982, but began rising again in themid-1990s. Despite public concern ollowing some high-prole rail crashes in the early 2000s,the number o rail journeys in 2004/05 was similar to the number in 1964.11

A major change in travel patterns in recent years has been the dramatic increase in the availability ocheap airline tickets, largely attributable to a deregulated airline market. The substantial increased ueluse associated with the massive increases in airline trac may have signicant environmental impacts.12

Infuences on current transport policy

The previous chapter noted increasing average distances travelled per person per year in Scotland. 1Much o this increase refects increased car ownership and an increase in people travelling by caror leisure and employment opportunities. There are several reasons or the increasing levels o carownership and usage in Scotland in recent years. Economic growth has meant an increase in demand

or transport. The real cost o motoring has dropped and transport users, particularly users o car andair travel, pay an articially low price or travel that does not refect the ull cost o each journey. 11Land use patterns have changed, with many services now dispersed and designed to be accessedand used by people in their cars.11

Levels o rail and bus travel both ell in the 1960s but have increased in recent years.11 Air travel hasincreased greatly in recent years, oering improved passenger value but with signicant increases in uelemissions that are inevitably associated with air travel. Despite growth in the use o public transportation,private car use also continues to increase and there are growing concerns about congestion andpollution attributable to road transport and doubts about the sustainability o both road inrastructureand uel supplies i current trends continue. For this reason, current transport policy seeks to balancethe benets and harms o road transport by reducing car use and promoting other orms o transport,while recognising that an ecient road network is vital to much economic activity. 8

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Recent Scottish transport policy

In 2004, the Scottish Executive published its rst transport white paper, Scotlands transport uture. 8This was ollowed by the Transport (Scotland) Act 2005,13 which is the rst legislation or transport thatocuses on the needs and requirements o Scotland alone. Specic issues o importance to Scottish

transport policy that were highlighted in the white paper include: more than 50% o the population is concentrated in Scotlands central belt

dispersed rural population outside the central belt

transport to the islands

high levels o deprivation in major cities.

The white paper set out the ollowing aim and objectives.

Aim: To promote economic growth, social inclusion, health and protection o our environmentthrough a sae, integrated, eective and ecient transport system.

Objectives:

promote economic growth by building, enhancing, managing and maintaining transport services,inrastructure and networks to maximise their eciency

promote social inclusion by connecting remote and disadvantaged communities and increasingthe accessibility o the transport network

protect our environment and improve health by building and investing in public transport andother types o ecient and sustainable transport which minimise emissions and consumptiono resources and energy

improve saety o journeys by reducing crashes and enhancing the personal saety o pedestrians,drivers, passengers and sta

improve integration by making journey planning and ticketing easier and working to ensuresmooth connection between dierent orms o transport.8

To achieve these, the white paper suggested that trac growth should be managed more eectively.It set a target that 70% o the transport budget should be spent on public transport by 2006, in orderto improve public transport inrastructure. The paper also suggested that it would be essential to changepeoples attitudes to their transport choices. The paper identied road user charging as a critical part o

demand management to reduce congestion and address environmental concerns.

The Scottish Executive has established Transport Scotland as an independent agency to takeresponsibility or capital investment projects and concessionary travel schemes. In addition, statutoryRegional Transport Partnerships (RTPs) have been ormed, charged with identiying regional transportobjectives and then identiying projects and initiatives to deliver these objectives. These priorities are tobe published in the orm o a Regional Transport Strategy (RTS). In turn, each o Scotlands 32 councilareas is expected to produce a Local Transport Strategy (LTS). LTSs will contain more localised proposalssuch as trac management schemes, road user charging schemes and home zone policies. ScotlandsNHS boards are expected to engage with RTSs and ensure their own travel plans are in accordance withnational and regional priorities.

Spatial planning policy is also relevant to transport. The Scottish Executive produces Scottish PlanningPolicies (SPPs) that state policy on land use and other planning matters. SPP17 is on Planning orTransport.14 It is accompanied by a planning advice note (PAN 75) to provide advice on good practice.15

These documents note that transport and accessibility should be included in development plans romthe outset. SPP 17 also emphasises that health benets should be one o the key objectives o transportplanning. It states that mode o personal travel should be prioritised as ollows: walking, cycling, publictransport and, nally, motorised modes. Major developments that are likely to produce signicant travelmovement require a transport assessment, the basis or which is analysis o the number o persontripsthe development is likely to generate.

Developments that require Scottish Executive approval or unding may also be subject to ScottishTransport Appraisal Guidance (STAG). STAG is an objective-led process that provides guidance on howto appraise and justiy all transport projects and policies.16 Local authorities are urther encouragedto require developers to produce travel plans as part o the development planning application process.Travel plans are described as documents that set out a package o positive and complementarymeasures or the overall delivery o more sustainable travel patterns or specic development.15

Health issues are linked to the environmental objectives o all recent transport policy. Sustainable

transport is a recurring theme in SPP 17.14 Green transport plans are oten recommended as a wayto achieve this. Green transport plans are described as a way by which organisations and businessmanage the transport needs o their sta and visitors. The aim o any plan should be to reduce theenvironmental impact o travel associated with work, whether by plane or car.17

Scotlands National Transport Strategy was published in December 2006. 18 The strategy is intended tobe consistent with the aims o the 2004 white paper. It ocuses on three main areas o work:

improving journey times and connections, to tackle congestion and the lack o integrationand connections in transport which impact on our high level objectives or economic growth,social inclusion, integration and saety

reducing emissions, to tackle the issues o climate change, air quality and health improvementwhich impact on our high level objective or protecting the environment and improving health and

improving quality, accessibility and aordability, to give people a choice o public transport,where availability means better quality transport services and value or money or an alternativeto the car (p6).18

It also states that sustainable development principles will orm the basis o our approach to this strategy(p6).18 This is intended to ensure that social inclusion, the environment and the economy are accordedequal importance in transport policy.

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Section 2: Evidence

Ruth Jepson, Hilary Thomson, Fintan Hurley and Margaret Douglas

02

Scope o the research reviewed

Transport research has ocused predominantly on road transport. As a result, this review o researchevidence presents limited evidence on train, erry or air travel and their possible links to health.

This chapter includes inormation on transport, access and health. The research evidence presented inChapter 4 ocuses on the observed associations between transport and health as well as links betweendierent modes o transport and health. Chapter 5 provides an overview o the available researchevidence o the health impacts o transport interventions. Evidence o associations rom cross-sectionalstudies can indicate potential ways to make transport healthier. However where possible, predictionso health impacts o an intervention should draw on research evidence that demonstrates the actualimpacts o an intervention or initiative. (See Appendix 2 or details o the searches used to identiyliterature or this review.)

The ocus o this report is policy interventions related to transport. The ollowing are not includedin this report:

walking, cycling or driving or leisure or sport purposes only (e.g. competition cycling, hill walking)

ways to increase physical activity unless this is to promote walking or cycling instead o car use

health impacts o transport policies that may promote dierent modes o transport to movereight, or example roads versus trains.

In HIA it is important to look or impacts on the whole population, not simply the intended recipients oan intervention. An individuals transport behaviour may aect their own health but also that o otherpeople. For example, an individual who chooses to drive may reduce his/her level o physical activity,subject him/hersel to in-vehicle pollutants and risk crashes with other vehicles. But he/she also increasespollution or the whole community and increases the risk o crashes or other road users, includingcyclists and pedestrians. This is oten not well addressed in research that looks only at impacts on

people who are the recipients o an intervention, or on the impact o individuals transport choices onthose individuals. When available, we have included research ndings showing impacts on the wholecommunity but oten this is not available. For example gures are available showing the risk o deathor serious injury or people using dierent modes o transport, but not the killed by rates or each othose modes. This issue should be borne in mind when using the evidence or HIA.

The primary unction o transport is the movement o people and goods between places, enabling

access to social and leisure activities, goods and services. As such, transport is an important determinanto health, particularly by acilitating access to key socioeconomic determinants o health.

The relationship between transport, access and health is complex. The relative importance o dierenttypes o transport will vary across dierent contexts and or dierent groups; thereore, reasons orchoosing a particular mode o transport may vary by area and individual. For example, in an area withexcellent public transport links, car dependency may be reduced and vice versa. There will also bespecic groups, or example those with mobility problems, or whom public transport is not a easiblealternative to a private car. Transport that is aordable and accessible is essential to enable essentialeconomic and social activities. Situations in which transport provision or access is not equal or allgroups may lead to social exclusion and inequality; the links between transport and social exclusion arediscussed below.

In the UK, where good access to essential economic and social activities is oten dependent on car travel,access to a car may lead to improved health. Two separate studies have shown a link between access

to a car and both physical and mental health; this link is independent o social class. Improved access toessential services acilitated by access to a car may explain this link to better health.19,20

Transport, social exclusion and inequalities

Data rom Scotland and the UK reporting links between poor transport and social exclusion aresummarised below: two out o ve jobseekers say lack o transport is a barrier to getting a job

nearly hal o 16- to 18-year-old students say they nd their transport costs hard to meet

over a 12-month period, 1.4 million people miss, turn down or choose not to seek medicalhelp because o transport problems.21

In Scotland, 67% o households have a car, but ownership is highly related to social class and income.For example, in Scotland 37% o households with an annual net income o under 10 000 own acar, compared with 98% o those with an annual net household income o over 40 000; 40% ohouseholds in the most deprived 20% o areas had access to a car compared with 86% in the leastdeprived 20% o areas.22

Although poor transport is only one aspect o deprivation, 23 it may aect other important actors relatedto social exclusion and deprivation.24 In urban Scotland, women, the unemployed, the elderly, peoplewith health problems and those in lowincome groups are more likely to experience transport-relatedsocial exclusion.23

Chapter 03: Transport,Access and Health



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Excluded groups are heavily reliant on walking, public transport and lits rom amily, riends andneighbours.23 Those living in households without a car report nding it harder to travel to get toshops, employment, healthcare and other services.21,25,26 Elderly people, people who are disabled and

others with health problems nd it dicult to use public transport, taxis or to walk.21

This suggeststhat in Scotland and the UK, lack o a car or access to a car may worsen existing levels o individualdeprivation and social exclusion. A study o mothers living on low incomes, who relied heavilyon walking, reported restricted access to essential services, amenities, shops and social networks.Although walking is a good orm o physical activity with health benets, i walking is the onlyaordable orm o transport there may be important negative eects on the welare o amilies,such as exclusion rom a range o services and acilities that are located in edge-o-town, car-riendlyretail parks.27

In terms o health, access to a car has been linked to improved health, irrespective o socioeconomicstatus (see Chapter 4). Rising levels o car ownership have led to increasing concerns about harmuleects on the quality o lie or groups without regular access to a car. In a context in which publictransport does not provide good access to essential services and amenities etc., it may be that accessto a car leads to improved health through providing convenient access and reducing an individualslevel o social exclusion. It has been suggested that planning decisions in the UK are oten based

around the expectation o car use by all, and that transport planners rarely think about how theirdecisions impact on less advantaged people, the elderly, and the disabled.28

Not only are less well-o people less likely to have access to a car but also, in addition, the lesswell-o and those living in deprived areas experience a disproportionate amount o the harmuleects o cars:

disadvantaged groups are more likely to be involved in a road crash28

the pedestrian death rate or children rom amilies in social class V is our timesthat children o social class I29

the road crash rate or children in Social Class V is alling more slowly than or childrenin social class I29

speeding is more common in less afuent areas 30

Urbanrural dierences

People in rural areas in Scotland have a greater reliance on cars and are more likely to hold a ulldriving licence, have access to a car, drive every day and drive to work.31 The high levels o carownership and car dependence may be explained by the greater distances required to travel to

access jobs, essential services and leisure opportunities, as well as the reduced access to publictransport compared with urban areas. Although those in rural areas with access to private transportmay be able to choose the services they access, or others, especially those without access to a car,issues o transport-related social exclusion may be compounded by their rural location.

A total o 369 deaths were registered in Scotland in 2001 as a result o injuries sustained in roadcrashes. Rural areas account or less than 20% o Scotlands population, but 66% o road tracdeaths are registered in rural areas; a disproportionately high level compared with the populationsize.31 However, it is not known whether those killed on rural roads are rural dwellers or urbandwellers travelling through a rural area. In addition, road casualty rates by distance travelled arelower or rural roads than urban non-motorway roads (see Table 2).

Transport interventions and health inequalitiesThe uptake and eects o any intervention may vary across dierent socioeconomic groups. For example,there is research evidence to suggest that those in more afuent groups adopt health promotionmessages around healthy liestyles more readily than their less advantaged counterparts.32,33 Theimplication o this is that health inequalities may increase; those in most need o health improvementare least likely to benet and the gap between the healthier afuent population and the less healthy,less advantaged population may increase. In terms o the impacts o transport interventions on dierentsocioeconomic groups, very little is known. However, it is possible that programmes to promote walkingand cycling instead o cars may be more eective in afuent groups. In addition, nancial penaltieson car use, or example uel tax, will inevitably have a disproportionate eect on those living on lowincomes, thus increasing the negative aspects o living in a car-dependent society or those who arealready disadvantaged.34 The possible dierential impacts o a transport intervention across dierentsocial groups must be considered i impacts on both health and social inequalities are o interest todecision makers who are planning a transport policy or initiative.

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Physical activity has been repeatedly linked with a range o improved health outcomes. The AmericanCollege o Sports Medicine has recommended that the level o physical activity required to improvephysical and cardiac tness is at least twenty minutes o any vigorous activity or up to sixty minutes o

moderate activity three times per week.37

But other health benets may be gained rom less vigorousand shorter spells o physical activity i undertaken regularly.

In the UK, the current chie medical ocers recommendation or adults is to accumulate thirty minuteso moderate-intensity activity, such as brisk walking, on most days o the week (at least ve days perweek). This moderate-intensity activity can be accumulated in several bouts o at least ten minutes andis sucient to bring health benets.38 Compared with people who are sedentary and do no exercise,people who are physically active have a reduced risk o death rom any cause. More specically, thereis a substantial reduction in the risk o developing major chronic diseases such as coronary heart disease,stroke, type 2 diabetes and cancer, especially colon and breast cancer, or those who are physicallyactive.38,39 Regular physical activity may also help with weight control and obesity prevention. 38 Muscleand bone strength may also benet rom regular physical activity; this can be o particular benet orthose at risk o alls and ractures, or example the elderly. Although there are reports o a link betweenimproved mental health and physical activity, the research evidence to support these links is less clearthan or the benecial links between physical health and physical activity.38,39 Adverse eects o physical

activity, or example injury or cardiovascular event, are also a possibility but the risks attached tomoderate exercise or those with no pre-existing disease are small. 38

Some modes o transport involve more physical activity than others; however, whether or not walking orcycling to work leads to an increased level o physical activity overall is not known, as walking or cyclingas a orm o transport may be used as a substitute or other orms o exercise. For example, someonemay start to replace car use with walking, but may subsequently stop an aerobic exercise class.

Determinants o physically active transportWith increasing levels o obesity there is growing interest within public health circles in the promotiono physical activity as a means o weight control and obesity prevention at a population level.38 Overalllevels o physical activity and physically active transport have been linked to characteristics o the localenvironment, in particular the urban built environment.40,41 For example, physically active transport (i.e.

walking or cycling) has been directly related to increased residential density, street connectivity, mixedland use and amenities within a walking distance.42 Identiying key determinants o physical activityor transport, rather than or leisure or sport alone, may help to shape strategies to help promotephysical activity through physically active transport. However, an expert review o this topic suggeststhat although characteristics o the built environment may help to acilitate physical activity, individualsociodemographic actors be a more powerul infuence on levels o physical activity and use ophysically active transport. In addition, studies have investigated a number o dierent measures o thebuilt environment and it is not clear which characteristics are most strongly linked to physically activetransport.41 This suggests that improving neighbourhood design alone is unlikely to lead to a substantialincrease in physical activity or use o physically active transport.

Transport and physical activity

Perceived saety and aesthetics o the neighbourhood have also been linked to using walking as a ormo transport.43,44 Available research suggests that weather is not an important infuence on levels owalking in a neighbourhood; however, much o this research comes rom Australia where there is less

inclement weather than in Scotland.

Physical activity is infuenced by many individual actors. There is some suggestion that physically activeleisure is more common among those with higher incomes, but those who work long hours (more thanorty-eight hours per week or men and more than thirty hours per week or women) are less likely toparticipate in physically active leisure.45 Access to a car is also a predictor o increased levels o physicallyactive leisure regardless o socioeconomic position.46

Cars are a sedentary orm o transport, minimising physical activity by allowing transportation rom door

to door. Around 58% o trips by car or van (either as driver or passenger) are under ve miles, a distancethat would take about thirty minutes by bike, and nearly 25% are under two miles (thirty minutes briskwalk).47 Although both health and transport disciplines link the increase in car use with the decline inphysical activity and rise in obesity at a population level, these links have not been ully established atan individual level: it cannot be assumed that someone who drives a lot will be less physically activethan someone who does not drive a lot. A project is currently under way in the UK to examine therelationship between car use and child health, including physical activity and obesity. Preliminary resultssuggest that higher car use in the amily is linked to lower overall levels o physical activity. 48,49

Cars and physical activity

Using public transport will oten involve walking to and rom the bus or train stops and may help

otherwise inactive groups become more physically active.50 In urban areas o Scotland, most peopleonly need to walk a short distance to their nearest bus stop (less than six minutes),23 and will also belikely to have a short walk at the other end to reach their destination. It is possible that using publictransport, where users walk to the service, may promote physical activity compared to door-to-doorcar travel. Whether measurable health benets would be realised rom this potential increase inwalking is not known.

Public transport and physical activity

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Walking and cycling as modes o transport are obvious orms o physical activity. The health benet romwalking or cycling instead o travelling by car will depend on the overall time and levels (light, moderateor vigorous) o walking or cycling done. As mentioned above, the health benet o physically active

transport, such as walking to school or work, will also depend on the impact on overall levels o physicalactivity. One study ound that boys who walked to school were more physically active than those whotravelled to school by car; however, there was no dierence in overall levels o physical activity betweengirls who walked or were driven to school.51

Overall assessment: Transport and physical activity

Walking and cycling are physically active orms o transport

The current recommendation or adults to achieve health benets is to accumulate thirtyminutes o moderate-intensity activity, such as brisk walking, at least ve days per week

It is not known whether increased car use is linked to reduced physical activity overallat an individual level

Physically active transport may lead to increases in overall levels o physical activity

Walking, cycling and physical activity

Road crashes

Physical injuries (atal and non-atal) are the main consequence o road crashes. An overview oUK injury rates, and causes o road trac crashes is presented below.

In 2004, 18 404 people were injured on Scotlands roads, o which over 2700 were seriously injuredand 307 were killed. O the 3007 people killed or seriously injured, 382 (13%) were children.52Historically, the killed or seriously injured casualty rates per head o population in Scotland havebeen higher than in England & Wales, whereas the all severities casualty rate has been lower inScotland than in England & Wales. In 2003, Scotlands casualty rates, compared with England & Wales,

were 9% higher (killed), 1% higher (killed or seriously injured) and 28% lower (all severities). In all threecases, this represented an improvement in the position in Scotland relative to that in England & Wales(compared with the 199498 average).53 In the UK, around 65% o road crashes occur in built-up areas,30% outside built-up areas and around 45% on motorways (see Table 2).

Transport-related injury and death

Table 2: Rates o crashes (all vehicles), users and pedestrians killed/seriously injured by road type (2004)(rate per 100 million vehiclekilometres travelled)

AccidentRates

Motorways 9 1.2 0.0

Urban A roads 70 6.3 3.2

Urban B, C and unclassied roads 64 5.3 3.2

Rural A roads 25 5.8 0.4

Rural B, C and unclassied roads 46 8.9 1.0

Users killed/seriously injured

Source: Department or Transport 2005. Road Casualties Great Britain: 2004 Annual Report.National Statistics publication (table 26)54

Pedestrians killed/seriously injured

Rates o road casualties (those killed or injured) have been consistently alling or over ty years acrossmost industrialised countries. In the UK, although there has been an increase in absolute numbers ocrashes, the absolute numbers o those killed on the roads in 2004 was 36% lower than in 1950. 54This signicant all in casualty rates is despite the massive increase in road trac. Between 1980 and2003, road trac increased by 79%, whereas the number o road crashes resulting in personal injuryell by 15%.55 The reductions in the numbers o crashes and casualties in recent years are even moresignicant, given the rapid increase in trac volume. For example, in 2003 the number o vehicleslicensed in Scotland was more than one-quarter higher than in 1993; trac on Scottish roads wasestimated to have grown by about one-th since 1993.53

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The risk o crashes varies, depending on the type o road, the trac mix, the time o day, climaticconditions, and the speed and mass o the vehicles involved. Although there are many contributoryactors to crashes, ocial road crash statistics do not record crash causation. Inormation based on the

opinions o police ocers collecting data at the scene suggests that the main contributory actors arespeed, careless or reckless behaviour, inattention, lack o judgement o own travel path and ailure tojudge other persons travel path.56

SpeedThe most requently cited contributory actor to atal crashes in the UK was excessive speed, recordedin 28% o atal crashes between 1999 and 2002.56 This compares with 18% o severe crashes and11% o slight crashes or which speed is cited as a contributory actor. Speed also aects injury severity;80% o pedestrian or cyclist atalities occur at impact speed between 20 and 40 miles per hour (mph),whereas atal impacts at 020 mph account or only 5% o atalities among vulnerable road users.Around 40% o pedestrians who are struck at speeds below 20 mph sustain serious injury, whereasat impacts o up to 30 mph, 90% sustain serious injury. 57,58

Driver sleepinessDriver sleepiness is another contributory actor to crashes. In the UK between 1995 and 2001,17% o road trac crashes (RTCs) resulting in injury or death were sleep related. The proportiono sleep-related RTCs varies between 3% and 30%, depending on the road type, time o day (morelikely during early hours o the morning) and use o articial lighting.59 A systematic review oundthat current epidemiological evidence or a causal role o atigue in car crashes is weak but suggestiveo an eect.60

Motorway service areas are provided or drivers to stop and rest. An investigation o road crash datarom two motorways in the UK over two to three years reports that there is little dierence in the rateo sleep-related crashes on stretches o motorway beore and ater motorway services areas. It is unclearwhether or not provision o motorway service areas or Tiredness kills - take a break signs help preventsleep-related crashes.61

Mobile phonesThere is considerable concern that using a mobile phone while driving creates a signicant crash riskto the user, and to other people on the road, because it distracts the driver, impairs their control o thevehicle and reduces their awareness o what is happening on the road around them.62 Using a mobilephone while driving has been reported to increase the risk o a road crash by our times; this increasedrisk was regardless o whether or not a hands-ree set was used. 63 In 2002 just under 1% o driversin Scotland were observed to be using hand-held mobile telephone equipment while driving. 64 InDecember 2003 a law came into orce to prohibit drivers using a hand-held mobile phone, or similardevice, while driving. Although this has reduced the use o mobile phone use while driving, it has notstopped the practice altogether.

Causes o road crashes and contributory actors

Drink-driving

Drink-driving is a signicant cause o crashes. Drink-drive casualties are dened as any road userskilled or injured in a drink-drive crash. UK estimates or 2003 suggest that 7% o all road casualties

and 17% o road deaths occurred when someone was driving while over the legal limit or alcohol.65In Scotland the number o people killed as a result o drink-drive crashes is estimated to have allenby around 20%, rom about 60 in 1992 to around 50 in 2002. The number o serious casualties isalso estimated to have dropped by 20% (rom roughly 310 in 1992 to 240 in 2002). 53

In the UK the absolute numbers o cyclists killed or injured (serious and slight) has allen by 32%,between the years 1994 and 2004, rom 24 385 to 16 648. In addition, the estimated number o milescycled has remained relatively constant over the same time period (in 1994, 4000 million kilometresversus 3900 million kilometres in 2004) so that the rates o cyclists killed or injured have also allen

substantially over the past decade. For example, rates or cyclists killed or seriously injured ell by 35%between 1994 and 2004.66 Casualty rates or cyclists in Scotland are substantially lower than in England& Wales (killed or seriously injured, 37% lower; all severities, 48% lower).53 This dierence may bedue to quieter roads.

Countries that have seen a modal shit in cycling have noted reductions in casualties as more peoplecycle. The increased saety or cyclists is explained by the eect o a critical mass. For example, amotorist is less likely to collide with a person walking and cycling when there are signicant numberso people walking or cycling.67 An illustration o this comes rom Copenhagen, where, over the past10 years, the number o kilometres cycled has increased by twice as much as the number o kilometresdriven, and the risk o a cyclist being involved in an RTC has reduced by hal between 1995 and 2000. 68Thus there is some evidence that in places and countries where cycling is common, cycling is saerthan in the UK, where cycling, as a means o transport, is relatively uncommon and provision orcyclists is limited.

The areas o highest risks or vulnerable road users such as pedestrians and cyclists are where minorroads intersect with arterial roads.69 Roads near houses and schools are high-risk areas or childrenand may restrict their levels o physical activity, including cycling and walking. Parents report the earo RTCs as the main reason or escorting children to school.70

Vulnerable road users: cyclists and pedestrians

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Severity o injury to pedestrians involved in a vehiclepedestrian collision may be infuenced by thesize and shape o vehicle. The risk o atal pedestrian injury is higher ollowing collision with a lighttruck (sport utility vehicles (SUVs), pick-up trucks and vans) than with a standard passenger car.71,72

The weight and size o the larger vehicle will aect the severity o injury but this is not thought toexplain the increased risk o atality. Light trucks and SUVs have higher bonnets and bumpers thanpassenger cars and so collisions with these vehicles are more likely to result in injury to the middleand upper body, i.e. to the head, chest and abdomen.73

The number o atalities rom train, aeroplanes, bus or erry crashes is small (see Table 3) and is largelyas a result o major crashes. In the UK, ewer than 20 atalities per year occur as a result o trainmovement, or example as a person enters or alights rom a train. 74

No UK government statistics were ound that reported the number o road crashes involving trams.However, two observational studies (in Sheeld, England, and Gothenburg, Sweden) ound thattrams can be a cause o crashes.75,76 In Sheeld the number o tram injuries presenting in the hospitalaccident and emergency department represented 0.13% o the patients attending the department.Cyclists appear to be the group at highest risk rom tram-related injury, ollowed by pedestrians andmotor vehicle users.75 For cyclists, the most commonly described scenario was one where the cyclewheels became stuck in the tram tracks resulting in loss o control o the cycle. In the Swedish study,a majority (60%) o those atally injured by a tram were under the infuence o alcohol and mostinjury events happened at or near a tram stop.75

Transport-related injury and death: othertransport modes (trains, aeroplanes, buses,erries and trams)

Although the number o people killed or seriously injured provides a simple measure o the dangero travel it makes no allowance or the number o people using a particular mode o transport or thedistance travelled. These can be taken into account by calculating casualty rates. 77 Motorcycles are the

most dangerous mode in this respect; walking and cycling are about hal as dangerous, with car, taxiand bus travel being many times saer (see Table 3). The relatively high rates o atality and injury amongcyclists and pedestrians need to be viewed in context. These rates are or crashes occurring on roads,where, in the large majority o cases, a motor vehicle will be involved. The inevitable actors o the speedand weight o a motor vehicle mean that unprotected road users, i.e. cyclists and pedestrians, are armore vulnerable to being killed or seriously injured i involved in a road crash.

Table 3: Passengers killed or seriously injured (KSI) rates per billion passengerkilometres travelled (2003)

Accidents by mode o transport

Note: Above rates taken romDepartment or Transport

Annual Report 2003, table 51

78

*Fatalities only

**19942003 average

Passenger casualties onUK-registered merchant vessels(includes all public erries andcommercial ships)

+Includes drivers andpassengers KSI

Mode o transport

Rail (2002/03) 0.4*,**

Air 0.01**Water 61**,

Road: car 27+

Road: van 10+

Road: bus / coach 10

Road: motorcycle 1264+

Road: cycle 534

Road: pedestrian 443

KSI rates

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Annual average PM10

is about 25 g.m3 (micrograms per metre cubed), and annual averagePM

2.5around 15 g.m3 in UK cities. In terms o overall contribution to PM in the UK, emissions

o primary particles rom local transport are the source that dominates measurements o PM atroadside locations (AQEG 2005, p373).81 Background urban concentrations o PM are aectedmore by regional (long-distance) sources, including secondary particles rom trac elsewhere.This dual contribution o trac to ambient PM highlights the importance o both local andinternational eorts to control air pollution rom trac.

Air pollution and healthAir pollution remains a public health problem associated with several adverse health outcomes.Although it has long been accepted that air pollution episodes lead to increased mortality andmorbidity, more recent research has established that normal levels o outdoor air pollution mayalso have adverse consequences. More than ten years ago there was already evidence that in thedays ollowing higher air pollution there were small but clear increases in:

premature deaths rom cardiorespiratory causes

respiratory hospital admissions

exacerbations o pre-existing asthma

respiratory symptoms, and

reductions in lung unction83

More recent studies have reported links between increased outdoor air pollution and both cardiachospital admissions, and other measures o cardiovascular morbidity.84

Note that although higher air pollution may worsen the symptoms o pre-existing asthma, it hasnot been established that air pollution initiates the disease.85 In particular, changes in air pollutionappear not to be the cause o the increase in asthma in the UK in recent decades.

The main cause o poor health ollowing exposure to increased air pollution is thought to beparticulate matter, although eects o ground-level O

3are also well established. The amount o

increased air pollution needed or health impacts to be observed is small. For example, in Europea rise o 10 g.m3 o PM

10is estimated to increase the number o daily deaths by 0.6%, with an

estimated 0.3% increase in daily death per 10 g.m3

o O3.86 These are small increases in dailydeaths and those at greatest risk are people whose health is already impaired, in particular thosewith existing cardiorespiratory disease. However, small increases in risks across a large populationmay have signicant public health impacts. The associations with PM are accepted as almostcertainly causal,87,88 leading to recommendations or more stringent control o ambient particles inthe UK and many other countries.

Although physical injuries (atal and non-atal) are the main consequence o transport crashes, theremay be other impacts. For example, post-traumatic stress disorder has been ound to aect one inthree children79 and one in ten adults80 involved in RTCs.

Overall assessment: Transport-related injury and death Travel by rail and aeroplane has the lowest rate o atality or serious injury

Road users at highest risk o being killed or seriously injured are cyclists and pedestrians

The most commonly cited cause o a road crash is speed

Rates o road crashes in Scotland are alling despite increased road trac

Rates o crashes involving cyclists are lower in countries where cycling is common

Very little research has been carried out on tram-related crashes

Other health impacts o transport crashes

Road transport as a source o air pollution in the UK

Air pollution is a complex mixture o particles and gases; and particulate matter (PM) is itsel a complexmixture. The pollutants most associated with trac are PM, nitrogen dioxide (NO

2) carbon monoxide

(CO) and toxicants such as benzene. PM10

measures inhalable particles o less than 10 microns indiameter, whereas particles measured as PM

2.5are smaller, at less than 2.5 microns in diameter.

Primary particles are those emitted to air as particles. With road transport, this is principally rom dieselengines, with some contribution rom the wear o brakes and tyres. Using data rom 2001, the AirQuality Expert Group (AQEG)81 (2005, table 4.11) reported that in the UK, road transport is responsibleor more than 30% o the emissions o primary particles measured as PM

2.5, and about 50% o the very

small (ultrane) particles (PM0.1

; less than 0.1 microns in diameter), which are, increasingly, believed toplay an important role in causing adverse health eects.

Secondary particles are ormed in the atmosphere through the chemical interactions o certain gases.Sulphates and nitrates are the two main components, with sulphur dioxide (SO

2) and nitrogen dioxide

(NO2), respectively, as precursor gaseous pollutants. SO

2emissions rom road transport are negligible.

However, road trac is responsible or almost one-hal o the nitrogen oxides (NOx) emitted into the airin the UK (AQEG, 2004, table 2.4; AQEG 2005, gure 4.7).81,82 NO

xis also a precursor o ozone (O

3),

at a distance rom the source o emissions. (Close to source, emissions o NOx lead to reductions inlow-level O

3.)

Transport, air pollution and health

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In addition, and much more importantly or public health, there are adverse consequences o longerterm exposure to outdoor air pollution, especially to ambient PM, at normal levels. This was highlightedabout 10 years ago when two large-scale cohort studies in the United States89,90 showed that, havingadjusted or other actors (individuals smoking habits, educational status, occupational exposure to airpollution), the risks o mortality are increased in cities with higher long-term air pollution. These resultshave been corroborated by urther re-analysis, longer ollow-up o the original studies, and studieselsewhere including in Europe,91,92 which have also ound relationships between longer term exposureto air pollution and mortality.

It is now widely accepted that the annual average concentration o ne particles (PM2.5

) is the bestavailable indicator or estimating the eects on mortality o long-term exposure to ambient air pollution.It is estimated that overall there is a 6% change in mortality per 10-g.m 3 change in annual averagePM

2.5.88,93,94 It has recently been estimated that this implies a reduction in lie expectancy o about 220

days per person, on average across the population o Britain, or every 10-g.m 3 increase in PM2.5

,compared with an estimated reduction in lie expectancy o less than 90 days attributable to passivesmoking.95 Bearing in mind that there are uncertainties in any estimates such as these, considering thecontribution o transport to annual average concentrations o outdoor PM

2.5in the UK, the reduction in

lie expectancy rom transport-related air pollution is estimated to be o the same order as the reductionrom passive smoking.

Health eects o trafc-related air pollutantsThe health eects o trac-related air pollutants were reviewed recently by the World HealthOrganization (WHO).96 This report has inormed much o the ollowing review o trac-relatedair pollutants and their health impacts.

Ambient particulate matter

As noted above, small particles, especially rom combustion sources, are the components o airpollution most strongly associated with adverse health eects. Although the evidence is by nomeans conclusive, it is now thought that, per unit mass, primary particles are relatively more toxicthan secondary ones; that, within the size range o PM

10, very small (ne, or ultrane) particles

are more dangerous than coarser ones; and that surace properties o particles, including transition

metals, have a bearing on toxicity.81,86,97

The gases: nitrous dioxide, carbon monoxide and ozone

There are standards or the control o NO2

that limit both short-term (one hour) exposures to veryhigh concentrations and long-term exposures. Epidemiological studies show associations between

NO2 and respiratory health but it may be that NO 2 is simply a marker or trac-related air pollutionmore generally. Control o NO

2is nevertheless important because it is a precursor o both secondary

particles and O3.

There is strong evidence that daily variations in O3

concentrations are associated with increases inmortality rom cardiorespiratory causes and with respiratory (although not cardiovascular) morbidity(e.g. see WHO 2003,97 200486) Currently, it is thought that there is no threshold at which O

3levels

start to aect health and that there is some risk to some o the population even at low backgroundlevels o O

3.86 It is unclear whether there are particular additional risks associated with long-term

exposure to ambient ozone.

Some studies also show associations between CO and ill health, or example cardiovascular hospitaladmissions.98 It may be that CO is acting as a marker or trac-related pollution.

Other pollutants: benzene an leadOther pollutants such as benzene or 1,3-butadiene pose only a small public health risk.In the UK lead has been phased out rom petrol.

Studies o trafc-related air pollution and health

It is dicult to assess, through epidemiology, whether PM rom trac is more toxic (per unit mass)than PM rom other sources. There is, however, some evidence that it is. The Air Pollution andHealth - A European Approach (APHEA) studies in Europe have shown that the mortality risksrom short-term exposures to PM are greater when concentrations o NO

2(a common marker

o trac-related air pollution) are also elevated, suggesting a particular toxicity o trac-relatedpollution.99 A study in the United States ound that the risks o mortality, per 10 g.m 3 PM

2.5were

three times as high when the PM was attributed to trac when compared to coal combustion as asource; PM rom crustal sources (e.g. sea salt, natural wind-blown dust) was not shown to be relatedto daily mortality.100

There is evidence o increased risk o mortality in people living near major roads; these risks may bedue in part to relatively high concentrations o ultrane particles in roadside air pollution, althoughother actors may also play a part. In particular, a study o the mortality (198694) o nearly 5000people in the Netherlands, aged 5569 in 1986, ound that deaths rom cardiorespiratory causeswere almost twice as likely (relative risk 1.95; condence interval (CI) 1.093.52) in people who hadlived within 50 m o a major road or 10 years or more.

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Although some relationships with air pollution were ound, it is not clear how much o this increased riskcan be attributed to the increased exposure to transport-related air pollution associated with living neara major road.91

As noted earlier, there is little evidence that exposure to air pollution is a cause o the increase in asthmanoted in many Western countries, including the UK. Nevertheless, the belie persists that transport,generally, and the associated air pollution in particular, is an important cause o the disease. Severalstudies have investigated the possible association between trac and prevalence/incidence o asthma,especially in children. Overviewing the limited number o studies available in 1995, the Committee onthe Medical Eects o Air Pollutants (COMEAP)85 ound that a consistent, though modest, associationbetween exposure to trac and asthma prevalence in children but was unclear i the association wascausal, especially with regard to initiation rather than provocation o asthma. The evidence is currentlybeing reviewed again by COMEAP. However, most studies since 1995 have examined asthma prevalencerather than incidence, making it dicult to clariy the role o pollution, and trac, in the initiation oasthma. There is evidence o association with heavy goods trac in particular though, i the associationis causal, it does not appear to be mediated via air pollution concentrations as measured conventionally.

In-vehicle concentrations and exposure to air pollutantsThe relationships between pollutant concentrations in vehicles and concentrations at backgroundmeasurement sites, i.e. away rom roadside or other immediate sources o pollution, were reviewed bythe WHO.96 Generally, in-vehicle United States and Europe ound that in-vehicle concentrations wereon average 45 times as high as measurements at background sites or carbon monoxide, 58 times ashigh or benzene, and lower, at about 1.5 times background, or NO

2. In London, in-vehicle PM

2.5was

more than twice the background level, with a much higher ratio or elemental carbon, presumably romdiesel.101 These are average ratios whose magnitudes vary in particular circumstances according to tracconditions, weather conditions and characteristics o the vehicle. As noted in the WHO report, 96 thedierences between background and in-vehicle concentrations refect both general dierences betweenbackground and roadside concentrations, which also aect cyclists and pedestrians, and some in-vehicleaccumulation relative to general roadside concentrations.

Mass concentrations o PM (e.g. PM10

or PM2.5

) in underground railways are typically much higher thanambient background levels in cities. However, studies o the London Underground showed that when

particle number rather than mass was considered, measurements were much lower underground thanabove ground.102 The dust underground is principally due to abrasion between wheels and rails, whereasgeneral ambient PM is mostly rom combustion, especially trac. Underground dust is consequentlymuch coarser than ambient particulate pollution, and has a dierent composition. Seaton et al102concluded that there were some risks to health rom pollution above and below ground but that thedierences were not big enough that they should infuence individuals choice o mode o transport.

Exposure to air pollution is infuenced not only by background rates but also by the time spentin various microenvironments and breathing patterns, which is, in turn, infuenced by the level ophysical activity. These vary by age, gender, occupation and so on. The volume o air inhaled perminute by cyclists and walkers is higher than by sedentary travellers in cars or in underground trains.

Overall assessment: transport-related air pollution and health Air pollution is a complex mix o particles and gases. Increased outdoor air pollution is

associated with increased cardiorespiratory mortality and morbidity. Some eects are moreor less immediate and aect vulnerable groups in particular, whereas the eects o long-termexposure are more widespread

Small particles (PM) are the constituent most closely associated with adverse health outcomes

Road transport is responsible or 30% o the emissions o PM2.5

, and about 50% o theemissions o PM

0.1

It is estimated that overall there is a 6% change in mortality per 10 g.m 3 changein annual average PM

2.5

For many pollutants, concentrations in vehicles are higher than background and general

roadside concentrations

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Motorised orms o transport are a common source o noise pollution, with road trac being themost common. Other sources o transport noise, such as rail and air trac, may be less common interms o people aected but may be regarded as a serious cause o noise pollution or those living orworking near a rail or air network. Noise levels are measured in decibels and Table 4 shows the levelsor dierent types o transport.

Table 4: Noise levels or dierent orms o transport

Road transport

The noise o motorised road vehicles is mainly generated rom the engine and rom rictional contactbetween the vehicle and the ground and air. In general, road contact noise exceeds engine noise at

speeds higher than 60 km/h. The level o noise rom trac is correlated with the weather, road suracetype, or example asphalt or cement, trac fow rate, vehicle speed, tyre width and vehicle type.Heavy vehicles, such as lorries and motorcycles, tend to be about twice as loud as motor cars. 107

No systematic review o the evidence on road noise was identied. However, noise rom roadintersections above 5060 dB(A) has been reported to cause sleep disturbance, 105 and road noisemay also deter people rom walking or cycling on busy roads.108

Walking and cyclingWalking and cycling are not a source o noise pollution.

Other transport modes: trains, airplanes, buses, erries and trams

Those living near to an airport will be exposed to high levels o noise, especially those living near anairport used by large numbers o jet planes. As indicated above the negative impacts o noise are mostcommonly annoyance, sleep disturbance and stress. Hearing loss occurs more rarely ollowing sustainedexposure to high levels o noise, most oten via occupational exposure.

One systematic review studied the health impacts o aircrat noise or those living near a busy airport.106The research evidence reviewed reported a range o physical and mental health impacts oten withcontradictory ndings. In addition, the quality o the research evidence available was poor, and increasedlevels o poor health among residents living near airports oten disappeared when socioeconomic status,age and sex were considered. In summary, there is no clear link between living in an area with highlevels o aircrat noise and mental or physical health outcomes. High levels o noise cause annoyanceand irritation, especially or those who are highly sensitive, but noise annoyance is not always anindicator o high noise levels.106

Living in an area with high levels o aircrat noise is associated with other impacts, such as sleep loss andreduced quality o sleep, but it is not clear whether this leads to urther health outcomes. The impact oaircrat noise on child health and educational perormance has been assessed among children living inthe three boroughs (123 schools) surrounding Heathrow Airport. Although levels o noise were linked tohigher levels o annoyance, perceived stress, poorer reading comprehension and reduced attention, thislink disappeared when the socioeconomic status o the children and schools were considered. 109

No research was ound investigating the possible health impacts o noise rom other modes o transportsuch as trains, erries and trams. However, possible impacts o transport noise will be similar and willdepend on the level o noise rather than on the specic cause or source.

Transport-related noise pollution and health

Decibels, A-weighted (dBA) Form o transport

120 Aircrat at take o

110

100 Pneumatic drill at 1 m

90 Lorry, motorcycle, underground train

80 Busy crossroads

70 Near a motorway

60 Busy street through open windows

50 Busy street through closed windows

40

30 Quiet room

20 Broadcasting studio

10 Desert

0

Source: adapted rom R. Tolley and B. Turton (1995) Transport Systems,Policy and Planning: A Geographical Approach, Burnt Mill, Harlow Essex:Longman Scientic & Technical, p279.103

About 65% o the population o the European Union are exposed regularly to sound levelso 5565 dB. These levels do not result in hearing loss but are enough to lead to seriousannoyance, intererence with speech and sleep disturbance.104,105 Stress has been suggestedas a possible mechanism through which noise may aect mental and physical health.106

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Overall assessment: Transport noise and health

Links between transport noise and health are inconclusive

Transport noise is unlikely to result in long-term hearing problems

Aircrat noise may lead to sleep disturbance and reduced quality o sleep There is no clear link between living near to an airport and other health outcomes

Public transport

Very little research exists looking at the mental health impacts o public transport. One review opassenger crowding on trains in the UK was identied. It is suggested that perceptions o crowding

and actual passenger density levels are not always closely linked. Where passengers do eelovercrowded this may lead to stress but the perceptions o overcrowding and related stress maybe mediated by eelings o saety and control, and amiliarity with the journey. 115

Overall assessment: Transport and mental health Links between physical activity and improved mental health are unclear

Access to a car is linked to improved mental health

There is little available research on the subject o road rage or public transport-related stressThere are many possible sources o stress or transport users, or example overcrowding on trains andtrac jams or cars. However, there is very little research evidence looking at the mode o transport andits eects on an individuals levels o stress and mental health.

One area that has been o interest is the links between commuting and stress. Commuting by car andtrain has been linked to elevated stress and blood pressure. It is dicult to compare dierent commuters

and dierent stress levels due to the multiple infuences on stress, in particular with job-related stresslinked to commuting. Journey duration, predictability and convenience, or example direct train route,number o road intersections, appear to be associated with lower stress levels.110113

Physical activityIncreased levels o physical activity may be linked to improved mental health in some groupsbut the research evidence to date is inconclusive.39

Access to a car

Access to a car has been linked to improved mental health independent o social class.This link has also been shown to be independent o sel-esteem and income.19, 20

Road rage

Road rage is a phenomenon that has been highlighted by the media in recent years. The label is nowcommonly associated with any orm o aggressive or antisocial behaviour that occurs when at least oneparty is involved in driving and may involve other road users such as pedestrians and cyclists. A study orecent UK surveys and media reports ound that although many people eel that they have been a victimo road rage, there is little reliable inormation on this and no real measure or estimate o incidence.National newspaper reporting would suggest that road rage incidents are a serious problem, but theincidence and prevalence o road rage is not accurately captured.114

Transport, mental health and stress

Cross-sectional data on the level o personal saety (excluding crashes), or example muggings, betweenthe dierent types o transport modes is not available. However, surveys and qualitative researchundertaken in Scotland suggest that perceptions o personal saety may aect an individuals decisionto walk, cycle or use public transport, especially ater dark.4

Walking and cycling

Streets dominated by motorised vehicles with reduced numbers o people on the streets may createa social environment that is conducive to increased crime, which then discourages more people romwalking,4 in particular women and children.116 It has been argued that the greatest contribution to sae,comortable walking is to encourage more people to walk.47

Public transport users

One survey ound that users o public transport experience a range o crime and nuisance. 117For example, in the UK over a twelve-month period:

5% o passengers report being threatened with violence

4% o passengers report being the victim o thet

11% o passengers report being stared at in a hostile or threatening way; and

12% o passengers report being deliberately pushed

Transport, personal saety and perceptions o saety

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Fear o crime emerges repeatedly in passenger surveys as being an important actor infuencing travelchoices.118 On the whole, womens ear is greater than mens, and women are more likely to avoidusing public transport as a result.117

Overall assessment: Transport and personal saety

Personal saety ears and ear o crime may deter people rom walking,cycling or using public transport.

A transport route may run near or through inhabited areas and communities. In some cases these routesmay run through a community such that it bisects the community. This is reerred to as communityseverance and is dened here as reduced access to local amenities and disruption o local socialnetworks caused by a physical barrier running through a community. For example, the route o a newroad, railway or transport acility may run through an existing community. Community severance mayalso ollow signicant increases in trac fow on a road that was not originally regarded as a barrier.

The severance eect o transportation routes may lead to reduced access to local services and acilitiesespecially or pedestrians and cyclists who eel unsae crossing a busy road. In addition, busy roadsmay disrupt social networks within a community; this may be o particular importance to those whorely heavily on local social networks, e.g. the elderly and parents with young children. A study o threeSan Francisco streets in the 1970s ound that the busier the trac on a street, the ewer riends andacquaintances were made with neighbours living on the same road.119

The health impacts o community severance are not known. Although access to essential servicesand engaging with social networks may be linked to health, the potential or a road to have asubstantial impact on these actors would depend on the specic nature o the severance and thereliance o the aected population on local services and networks bisected by a new road or railroute or increased trac.

Overall assessment: Transport, community severance and health

New transport routes running through an existing community may lead to community severance

Substantial increases in trac through a community may lead to community severance

The health impacts o community severance are not known

Transport and community severance

Climate change and transport

The Department or Transport estimates that transport accounted or 22% o carbon dioxide (CO2)

emissions in the UK in 1995; road transport accounts or 95% o all transport emissions.120 Although

measures to reduce carbon emissions have been introduced nationally, transport is the only sector inthe UK in which carbon emissions are still increasing.121 These gases collect in the earths atmosphereand act to increase the earths surace temperature, causing complex changes in the climate system. 122The United Nations Intergovernmental Panel on Climate Change (IPCC) concluded that there is strongevidence that the Earths climate system has demonstrably changed since the pre-industrial era. In thepast century the global mean surace temperature is thought to have risen by around 0.6oC ( 0.2C).The IPCC states that it is likely that the 1990s were the warmest decade on record and orecastscontinuing increases in CO

2, surace temperatures and sea levels during the twenty-rst century. 123

Historically there have been major changes in climate and some change seems to be an essential parto the global weather system. Some debate remains about the exact amount o recent climate changeattributable to human activity, specically that attributable to large increases in ossil uel use comparedwith the pre-industrial era. However, there is no doubt that human activity has led to increasedconcentrations o greenhouse gases and aerosols. The scientic consensus expressed by the IPCC isthat most o the warming over the past 50 years is attributable to human activity. 123

Climate change and health

Climate change is thought to have already caused health impacts. The WHO estimates that in 2000climate change was responsible or approximately 2.4% o cases o diarrhoea worldwide, and 6% omalaria cases in some middle-income countries. Climate change was estimated to have caused 150 000deaths and 5.5 million disability adjusted lie years (DALYS) in the year 2000.124

A model illustrating how climate change may lead to health impacts suggests a number o routes or,and a range o, possible health impacts.125 Climate change could have benecial impacts in causingsome reduction in winter mortality in temperate countries. However, most o the health impacts oclimate change are likely to be adverse and are predicted to include:123,124,126

direct impacts o thermal stress in heatwaves

death and injury associated with natural disasters, such as foods and storms

inectious diseases caused by changes in the seasonal ranges o disease vectors, such as mosquitoes

ood and water-borne disease: WHO estimates that incidence o diarrhoea is 10% higher in someregions than it would be in the absence o climate change

altered transmission o other inectious diseases

cardiorespiratory and allergic diseases associated with changes in air pollution and aeroallergen levels

malnutrition caused by changes in plant pests and diseases, droughts and amine, and

the impacts o population displacement due to natural disasters, crop ailure, water shortagesand confict over depleted natural resources

Transport and climate changeb

b Where possible this review draws on research which has reported on observed links between atransport actor and a health or related outcome. For evidence on the size or amount o health impactattributable to climate change the review draws on estimates and predictions o health impacts.

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Table 5 (continued): Summary o hypothesised links between road transport and health with strengtho supporting research evidence*

Roadtransportfactors/impactsandhypothesisedlinkstohealthorrelatedsocialoutcomes

Transport

actor

Lin

kstohea

lthan

dre

latedsocialou

tcomessuppor

tedbyresearc

hev

idence

2++

2++

Phys

icalact

ivity

Mo

deratep

hys

icalac

tivi

ty,

suchas

briskwal

king,

acc

umu

lating

tothirtym

inu

teson

fve

days

perwee

kisrecommen

ded

oradu

lts

tobenef

theal

th.

Regu

larmo

derateac

tivitymay

lead

to

red

uce

drisko

chron

icdiseasean

ddea

thromanyc

ausean

dmay

helpcon

tro

lweig

htan

d

pre

ven

to

bes

ity.

Phys

icalac

tivi

tymay

haveapro

tect

ivee

ectonmen

talhea

lth

.

SoE

3

Commun

ity

severance

May

disrup

tloca

lsocialnetworksan

daccess

toloca

lservices

bu

tpo

ten

tial

or

impac

tw

illvary

substan

tial

lybyareageograp

hy.

Hea

lthimpac

tsareun

known.

3

Airpo

llution

Trafccon

tribu

tes

toou

tdoorairpo

llution.

Bo

thshor

t-an

dlong-termexposure

toam

bien

t

part

icu

latemat

ter

(PM)increases

theriskso

dea

tha

nddisease

romcard

ioresp

iratorycauses.

Somee

ectsaremoreor

less

immed

iatean

da

ectvu

lnerab

legroups

inpar

ticu

lar,w

hereas

the

eectso

long-termexposurearemorew

idespre

ad.

InBri

tain

,long-termexposure

to

transport-relatedairpo

llutionmeasure

das

PM2

.5isest

imated

tore

duce

lieexpec

tancy

bya

ew

mon

ths,ane

ectsim

ilar

tothees

timatede

ect

opassivesmo

king.

3

No

isepo

llution

No

tsu

fcien

ttolead

tohearing

loss,

bu

tislikely

toc

ausesleep

disturbance

or

those

living

inthe

immed

iatevicin

ityo

a

busystreetormo

torwa

y.Other

hea

lthe

ectsareun

known.

3

Personalsa

ety

Maya

ect

dec

isions

towal

k,cycleorusepu

blictran

sport

bu

thea

lthe

ectsareno

tknown.

2-

Stress

Trafcconges

tionmaycauseshort

termelevat

ionsin

stressmar

kers

bu

tposs

iblelong-term

eec

tsareno

tknown.

This section draws on systematic reviews o research evidence o the health impacts o transport

interventions (see Appendix 2 or the search strategy). The term transport intervention is used hereto reer to any deliberate activity, initiative or policy. These interventions can range rom the legalenorcement o seat belt use to investment in trac calming, road design, driver education campaignsand initiatives promoting active commuting, or example cycling to work.

As with the previous section, the research reviewed ocuses on road transport. This refects thedearth o research into the health impacts o non-road transport. In addition, transport research hasbeen dominated by interests in injury reduction and thus much o this section reports the impacts ointerventions designed to reduce crashes; there is much less evidence on the impacts o other kinds ointervention. Despite extensive literature searching, no research reviews were identied that evaluatedthe health or social impact o interventions or air travel, travel by railways (heavy or light) or erries.

Although a HIA should consider a range o potential impacts, including unintended impacts o aproposed intervention, available research has tended to study a very small range o outcomes and otenocused solely on the intended outcome, most oten injury reduction.

The interventions considered are the health impacts o:

new transport inrastructure

interventions to reduce road trac and uel consumption

interventions to reduce air pollution

interventions to reduce noise pollution

interventions to promote modal shit to walking and cycling instead o car use

interventions to improve psychosocial aspects o public transport

interventions to reduce crashes

Chapter 05: Health and Health-relatedImpacts o Transport Interventions

The building o new transport inrastructure, or example a new road, airport or train station,may have signicant impacts on the aected area.

New inrastructure: roads

One systematic review has been undertaken in this area. The review summarised studies that hadevaluated the health impacts ollowing construction o new roads and/or upgrading o existing roads.Details o the studies reviewed are reported below.127 A summary o the impacts reported in thesystematic review is provided in Table 6.

The health impacts o new transport inrastructure

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Most o the studies in the review examined either impacts on road injuries or disturbance among localresidents. No studies were identied that examined the impact o new roads on access to healthcare,health inequalities or physical activity. There was sparse evidence on outcomes

HIA of Transport Initiatives a Guide - HS IOM Scotland - 2007

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