1.1.1 There is increasing recognition of the interrelation between transport, the environment and health (Road Transport and Health, British Medical Association, 1997). Transport affects health in a number of ways, both positive and negative. The overall health effects of transport are summarised in Table 1 below (based on Health Education Department, 1998).

Table 1: Effects of Transport on Health

Health Promoting	Health Damaging
Accessing employment	Traffic Injuries
Accessing shops	Air Pollution
Accessing recreation	Noise and Vibration
Accessing social service support networks	Stress and Anxiety
Accessing health services	Danger
Accessing countryside	Loss of Land and Planning Blight
Recreation	Severance of Communities by Roads
Physical fitness (active modes)

1.1.2 In relation to health and transport, the Government's Transport White Paper, A New Deal for Transport: Better for Everyone (DETR, 1998) sets the framework to:

improve air quality by reducing pollution from transport;
reduce noise and vibration from transport;
improve transport safety for users, those who work in the industry and the general public; and
encourage physical fitness by reducing reliance on private cars and making it easier to cycle and walk more frequently.

1.1.3 The key indicators in relation to transport and health relate to accidents, air pollution, noise, physical activity and accessibility to people and services. With the exception of physical activity, all of these issues are addressed elsewhere in the guidance under their own objectives or sub-objectives. To include them under a health objective would introduce double counting into the assessment. Consequently, the remaining key impact relating to health that has not been considered elsewhere in the AST is personal physical activity, or to avoid confusion - physical fitness.

Further Impacts

1.1.4 Any impact of a strategy or plan of accessing health facilities, such as leisure centres and health clubs, should not be included in the Physical Fitness sub-objective, but considered under The Accessibility Objective (TAG Unit 3.6).

1.1.5 Whilst the health benefits of increased non-motorised travel should be considered under the Physical Fitness sub-objective, there could be impacts on other objectives that the analyst should ensure are considered. In particular there could be impacts on safety if there are significant increases in the extent of pedestrian and cycling movements and the plan does not necessarily include mitigating safety measures.

Physical Fitness

1.1.6 The range of health outcomes influenced by physical activity is considerable (Pearce, 1998). The risk of coronary heart disease, one of the biggest causes of death in this country, is double for an inactive person compared with an active one. Experimental evidence (Hillman, Boyd and Tuxworth, 1999) has further suggested that significant improvements in fitness and well-being can be obtained though relatively modest amounts of cycling; the effects were most evident in those who cycled 30km or more per week.

1.1.7 More exercise would help to reach the Government's proposed target for reducing coronary heart disease and strokes in England (DOH, 1998). The recommended minimum level of activity for adults is to build up to thirty minutes or more of moderate activity, most days of the week. This level of activity could be integrated into everyday life, including cycling and walking.

1.1.8 The most detailed research to date on cycling activity shows that the relative risk of an active cyclist of all-cause mortality is 72% relative to the prevalence of mortality in the population as a whole, based on data from the Copenhagen heart study (Andersen et al, 2000). In this study, three hours of exercise per week was required in order to reduce the relative risk to this level. It is assumed that there is a dose effect where greater levels of activity yield greater benefits to individuals, especially those induced to cycling from a relatively inactive lifestyle. The appraisal of physical fitness should reflect the change in activity, and hence relative risk of all-cause mortality, based on the average distance and speed that individuals travel as a result of an intervention. A unit cost saving of decreased mortality through increased activity may be derived using cost of death estimates.

1.1.9 For interventions targeted at cycling and walking promotion, a monetary value will often be appropriate here, since this is a relatively important part of the scheme benefit. For schemes primarily involving other modes, the effect on health will be important where it is demonstrated that there is significant mode shift due to the intervention to or from active modes. The World Health Organisation has produced a tool, The Health Economic Assessment Tool for Cycling (HEAT), which assesses the economic health impact of a change in volume of cyclists (WHO, 2007). This methodology is adopted for use in economic appraisal and described in Guidance on the appraisal of walking and cycling schemes (TAG Unit 3.14.1). This may be used to assess the potential impact of mode shift and its inclusion in the appraisal figures. It should be noted that relatively modest changes in walking and cycling can lead to significant economic benefits or disbenefits.

1.1.10 Whilst a thirty minute level of activity sounds a high absolute figure, existing activity levels (for example, walking to shops during lunchtimes or around offices) may mean that benefits could arise through changes in the level of activity which last for less time than this level would suggest. Similarly, if it is assumed that over the course of a day the outward and return journeys are made, then a single journey time of 15 minutes by foot or cycle would achieve this level. When undertaking an economic appraisal of the health impact, the practitioner should determine the relative dose effect of increased or decreased activity, since even minor walk trips may yield benefits for individuals that were previously sedentary.

1.1.11 Consideration of the health implications of transport proposals could therefore be identified through an assessment of changes in the opportunities for increased physical activity through cycling and walking. Providing increased opportunities to walk and cycle may also have additional benefits including improvements to the physical environment within communities, fostering well-being and community spirit which also have implications for health.

1.2 Methodology for Plans

1.2.1 In preparing inputs for the AST the changes in the extent of walk and cycling should be estimated using forecasting tools or methods where walking or cycling measures are key to the strategies or plans being considered (see Guidance on the appraisal of walking and cycling schemes, TAG Unit 3.14.1). Section 11.3.8 of the Design Manual for Roads and Bridges (DMRB) gives further practical guidance where there are local impacts that may lead to significant changes to journey times or lengths for active modes.

1.2.2 The key objective of the AST entries is the identification of the contribution of the strategy or plan to overall health by changing the level of physical activity. Within this indicator there is a reverse dichotomy at play: reducing journey times, which is a key benefit in economic assessment terms, can reduce the health benefits of these activities. Conversely, increasing the extent of walking and cycling may extend journey times which may then reduce economic benefits, but can increase the health benefits. There is, however, an obvious limit to which this can be taken; at some point, participants cease the activities completely, thus completely removing the health benefits.

1.2.3 Consequently, the key is the encouragement of walking and cycling, without significantly affecting the health benefits of existing participants. With this in mind, the economic value should consider both the journey times and the change in the demand levels. For calculation of the health benefits, the practitioner is required to estimate the following:

change in the number of persons walking and cycling;
average time travelled by active mode by users per day (calculated from average distance and speed along the specific route or area);
resultantly, the change in relative risk in the population of all-cause mortality.

1.2.4 This methodology estimates the benefit to the population using active modes for any level of activity, not just those achieving a specific threshold. There are four levels of benefit which can be considered:

for any new walk and cycle trips (shifting from mechanised modes) there will be some health benefits to each individual;
for existing walk and cycle trips, health benefits may change where the following may be impacted by a transport intervention:
trip distance (route choice may change based on more direct routing, as an impact of changes to severance);
where the journey time remains very similar (i.e. no introduction or removal of severance, no changes in travel speeds or route choice, etc.), health benefits will be largely unchanged; and
for existing walk and cycle trips, where the journey time falls, there will be reductions in health benefits.

1.2.5 At a plan level, in circumstances where the impacts are likely to be significant and data and forecasts are available, the impact on physical activity due to changes in walking and cycling on should be monetised explicitly (see Guidance on the appraisal of walking and cycling schemes, TAG Unit 3.14.1). Where the impacts are likely to be significant it will be expected that detailed data and forecasts will be used since walk and cycling should have been considered thoroughly in the forecasting processes.

1.2.6 It may be difficult to extract the information directly from a traditional transport model used for scheme appraisal where many of the short trips forecast would be classed as intrazonal and hence not covered. These would be likely to be too short to be of benefit for those trips where walk and cycle might be considered alternatives to car or public transport. Where significant mode shift does occur, it should be acceptable to assume some average time travelled for walkers and cyclists in order to calculate the changes in physical fitness benefits where this data is not directly available from the model.

1.2.7 Where journey times for existing cyclists are reduced due to the provision of cycle lanes it should be assumed that effect on activity will be neutral, the journey times reducing due to higher travel speeds. It is possible that this may cause some complications in obtaining data from detailed forecasting procedures. In such cases, or others where the use of a journey time measure is not possible or inappropriate, then a journey distance threshold can be used to replace the journey time measure. For cyclists this should assume a threshold of 10 kilometres per day (implying a cycling speed of 20 kilometres per hour).

1.2.8 Where significant levels of mode shift are expected from a scheme, particularly in the case of investment in walking and cycling infrastructure and/or Smarter Choice measures, the physical fitness benefits should be monetised (referring to the methodology in TAG Unit 3.14.1). The entry in the Overall Assessment column should be the economic value of changes to health through increased or decreased levels of activity that result from the scheme, the impacts on pedestrians and cyclists being identified separately.

1.2.9 In summary the physical fitness benefits are calculated thus:

the change in all-cause mortality rates as a result in the change in activity (assuming a linear dose response in line with the findings of the Copenhagen study);
resultantly, the expected number of deaths in the population with and without the intervention;
hence, lives saved (or lost) as a result of the scheme;
using the standard economic value of a life (see The Accidents Sub-Objective, TAG Unit 3.4.1), the total benefits generated by the scheme.

1.2.10 In schemes that are demonstrated to have a relatively insignificant impact on physical activity, such as inter-urban road building, it will be satisfactory to enter a qualitative indicator in the AST, showing separately the forecast changes in the numbers of cyclists and pedestrians. "Insignificant" in context means that the impacts are recorded as neutral, or in some marginal cases, slight. Where there is some evidence that the impacts may be more than slight, explicit monetisation of the benefits/ disbenefits should be undertaken. This includes interventions that may, for example, ease travel by motorised modes and encourage car use rather than active modes.

1.3 Methodology for Strategies

1.3.1 The methodology set out above for plans where the impact is likely to be insignificant should be applied to strategies, unless the strategy has specifically developed walking and cycling plans. It is likely that more general conclusions will be reached, but it should still be possible to generate an appropriate assessment score for the AST.

1.4 Application of TAG to Highway Schemes

1.4.1 Where the intervention to be appraised is considered to have a significant impact on active modes, usually where the intervention is walking or cycling infrastructure or a Smarter Choices initiative, the practitioner should follow the guidance in TAG Unit 3.14.1. Such interventions will have sufficient impacts on walking and cycling to warrant a full assessment of physical fitness, which is a relatively large appraisal benefit for these schemes. The success of these appraisals depends on the quality of forecasting and assumptions, which are covered in the Unit. It should be noted that even moderate changes to physical activity can yield relatively large economic benefits or disbenefits. For these schemes a monetisation of physical fitness benefits for both walkers and cyclists should be stated in the AST.

1.4.2 For interventions that clearly have an insignificant impact on active modes (e.g. motorway widening), a brief qualitative statement may be made in the AST once this fact has been established. For those judged to have a minimal impact at most, one should put in the AST forecasts of the change in numbers of walkers and cyclists as well as the impact on average journey times. Again, these interventions will be recorded as either neutral or slight only; schemes with a larger impact should be monetised explicitly.

2. Further Information

The following documents provide information that follows on directly from the key topics covered in this TAG Unit.

For information on:	See:	TAG Unit number:
Appraisal Summary Table	Transport Appraisal and the New Green Book The Appraisal Process	TAG Unit 2.7 TAG Unit 2.5
The correspondence between the advice set out in TAG and DMRB	Applying the multi-modal new approach to appraisal to highway schemes	TAG Unit 2.6
Policy background to the physical fitness sub-objective	A new deal for transport	See transport policy links
Appraisal of active modes	Guidance on the appraisal of walking and cycling schemes	TAG 3.14.1

3. References

Andersen, L B, Schnohr, P, Schroll, M, Hein, H O, (2000) All-Cause Mortality Associated With Physical Activity During Leisure Time, Work, Sports, and Cycling to Work, Archives of Internal Medicine, Vol. 160, pp1621-1628.

British Medical Association (1997) Road Transport and Health.

Hillman, Boyd, Tuxworth (1999) Promoting Cycling as a Way to a Healthier Life - Proceedings from Velo City 1999, Graz, Austria (11th International Bicycle Planning Conference).

Health Education Authority (1998) Transport and Health: A Briefing for Health Professionals and Local Authorities.

Department of Health (1998) Our Healthier Nation: a contract for health, CM 3854.

L M Pearce (TRL) A L Davis (Adrian Davis Associates) Dr H D Crombie (Independent Consultant) and HN Boyd (Allot and Lomax) (1998) Cycling for a Healthier Nation, TRL Report 346.

DETR (July 1998) A New Deal for Transport: Better for Everyone.

Highways Agency Design Manual for Roads and Bridges (DMRB).

World Health Organisation (2007) Economic Assessment of Transport Infrastructure and Policies, Copenhagen.

4. Document Provenance

This Transport Analysis Guidance (TAG) Unit is based on research and consultation to improve the Department's guidance on appraising walking and cycling (TAG Unit 3.14.1). This is an update to the previous guidance of June 2003.

This Unit became definitive guidance in April 2009.

Technical queries and comments on this TAG Unit should be referred to:

Integrated Transport Economics and Appraisal (ITEA) Division
Department for Transport
Zone 3/06 Great Minster House
33 Horseferry Road
London
SW1P 4DR
itea@dft.gsi.gov.uk
Tel 020 7944 6176
Fax 020 7944 2198

Updated: April 2009

Documents

Guidance documents - Expert

3.3: The Environment Objective

TAG unit 3.3.12: The Physical Fitness Sub-Objective

WebTAG

Department for Transport

Transport agencies

Transport bodies

UK Government

Key