About transport and health

This section provides information on how transport impacts on human health in Aotearoa New Zealand. 

The importance of transport in our lives

Transport plays an essential role in New Zealand society. In fact, New Zealand has the highest vehicle ownership rate per capita in the OECD [1]. Transport connects us to healthcare services, education, family, community, shops and recreation. We rely on transport to get from one point to another, move goods around, get to work, and for everyday life. 

Cars are the main form of transport used in New Zealand. In 2015-18, New Zealanders spent the vast majority (83%) of their total travel time in motor vehicles. Much less travel time was spent walking (10%), on public transport (4%) or cycling (2%) [2].  

How does transport affect health?

Transport can impact our health through a number of ways, including:

• road traffic injuries and deaths
• air pollution
• noise pollution.

A lack of transport can also lead to social isolation and create barriers to accessing services, including healthcare. Motorised transport also relies heavily on fossil fuels, which contribute to greenhouse gas emissions when burned.

By contrast, active transport (such as walking and cycling) and public transport have positive health benefits, such as improvements in mental well-being, physical activity, and cardiovascular health [3]. 

Road traffic injuries and deaths

Worldwide, road crashes are estimated to result in 1.3 million deaths annually and are a major contributor to the global burden of disease [4]. 

Road traffic crashes cause several hundred deaths in New Zealand each year (Figure 1) and many more injuries. Younger people tend to have the highest rates of road crashes and deaths [5].  

Figure 1: Annual road toll in New Zealand, 1990-2019

Air pollution from road transport

Motor vehicles contribute to air pollution in New Zealand, particularly in Auckland [6]. Vehicle emissions from burning petrol and diesel include particulate matter (PM10 and PM2.5), nitrogen dioxide, carbon monoxide and other gases. 

Exposure to particulate matter can lead to chronic respiratory and cardiovascular diseases, some cancers and low birthweight [7, 8, 9, 10]. Nitrogen dioxide is associated with acute respiratory effects such as asthma symptoms, especially in children [8, 11]. 

In 2012, there were 218 deaths in New Zealand due to air pollution (PM10) from motor vehicles [25].  

Active transport (walking and cycling)

Active forms of transport, such as walking and cycling, have a range of environmental benefits, including producing no air pollution, noise pollution or greenhouse gases. 

Walking or cycling for transport helps integrate physical activity into everyday life. The health benefits of active transport include [3]:

• increased physical activity
• improved mental health
• reduced risk of diseases, such as cardiovascular diseases and cancer.

Active commuting (walking or cycling) has been found to decrease cardiovascular risk by 11% [12].  Active transport could help reduce New Zealand's high obesity rate [13].  

A study found that moving 5% of short urban car trips to cycling in New Zealand would result in 116 fewer deaths through increased physical activity, six fewer deaths due to local air pollution from vehicles, and an additional five cyclist deaths from road crashes, each year [14].

Active forms of transport also have economic benefits in New Zealand, saving $4.27 per km for each new walker, and $2.14 per km for each new cyclist, according to a 2008 transport cost-benefit analysis [15].  

Public transport

Using public transport can also bring health benefits. Public transport increases physical activity, as it often requires travel on foot for part of the journey.

Public transport use also reduces air pollution, is safer than travelling by car, and can improve mental health [16, 17]. At average occupancy, public transport produces fewer harmful emissions than private vehicles [3]. 

Noise pollution from road transport

Road traffic noise can also affect health through annoyance, high blood pressure and cardiovascular disease [18, 19]. Noise pollution from traffic can also affect people's sleep patterns and impair cognitive performance.  

For children, noise pollution from traffic can interfere with their ability to learn, and increase their risk of cognitive and behavioural problems [3, 20, 21, 22]. 

Most road traffic noise is caused by motorised vehicles, particularly the sound of tyres on the road, as well as engines, brakes and exhaust systems [23].  People more exposed to road-related noise include those living close to busy roads and low-income groups [24]. 

The World Health Organization (WHO) estimated that 1.0-1.6 million healthy life years are lost every year from traffic-related noise in western European countries [20]. 

The burden of disease from road transport in New Zealand

We recently estimated that road transport was responsible for 650 deaths in New Zealand in 2012 [25]. These deaths included:

• 308 deaths due to traffic crashes
• 218 deaths due to particulate matter (PM10)
• 65 deaths due to nitrogen dioxide exposure
• 59 deaths due to noise pollution.

Additionally, an estimated 40 deaths were avoided through active transport, via the health benefits associated with increased physical activity.

Calls for a more sustainable transport system

Sustainability is defined as meeting the population's needs and ensuring a good quality of life, without compromising the ability of future generations to meet their own needs or quality of life [3]. 

Many organisations have called for transport systems to shift away from heavy reliance on cars and motorised vehicles, towards healthier and more sustainable forms of transport [3, 21, 26].

The New Zealand College of Public Health Medicine has called for the 'development of a sustainable transport environment where active travel and public transport are prioritised and represent realistic and safe alternatives to travelling by car' [26].

Barriers to the use of active and public transport

The use of active transport and public transport can be limited by several barriers, including concerns about road safety, a lack of safe places to travel, and poor urban design.

Traffic speeds and volumes can affect how people choose to travel.  For example, one of the major barriers to cycling remains the real (and perceived) risk of injuries. Higher levels of walking and cycling tend to occur in areas with lower traffic volumes [3]. A study in London showed that reducing speed limits to 20 miles per hour (30 km/h) reduced road injuries by 42% [27].  

Public transport also needs to be reliable, affordable, frequent and easy to use, for people to use it.  In smaller towns and rural areas, public transport is often not available.

Environmental Health Indicators for transport

You can find the following indicators on our EHI website:

• Number of motor vehicles
• Main mode of transport to work on Census day
• Household travel time by mode of transport
• Active transport to and from school
• Unmet need for GP services due to a lack of transport
• Road traffic injury deaths and hospitalisations

References

1. OECD. (2013). Environment at a Glance (Figure 2.11. Motor vehicle ownership, 2011 or latest available). Geneva: Organisation for Economic Co-operation and Development. 

2.  Ministry of Transport. (2014).  New Zealand Household Travel Survey: Regional results (3-year moving average). Available online:  http://nzdotstat.stats.govt.nz/wbos/Index.aspx?DataSetCode=TABLECODE7432 (accessed 2 March 2017).

3. British Medical Association. (2012). Healthy transport = healthy lives. http://bma.org.uk/transport

4. Bhalla, K., Schotten, M., Cohen, A., et al. (2014). Transport for health: The global burden of disease from motorized road transport. Global Road Safety Facility, The World Bank; Institute for Health Metrics and Evaluation, United States of America. 

5. Ministry of Transport. (2016). Young Drivers 2016. Wellington: Ministry of Transport.

6. Kuschel G, Metcalfe J, Wilton E, Guria J, Hales S, Rolfe K, et al. (2012). Updated Health and Air Pollution in New Zealand Study. Volume 1: Summary report. Prepared by Emission Impossible and others for Health Research Council of New Zealand, Ministry of Transport, Ministry for the Environment, and NZ Transport Agency. Available online: http://www.hapinz.org.nz/

7. Beelen, R.; Rasschou-Nielsen, O.; Staffogia, M.; Andersen, Z.J. et al. (2014). Effects of long-term exposure to air pollution on natural-cause mortality: An analysis of 22 European cohorts within the multicentre ESCAPE project. Lancet 383, 785–795.

8. Hoek, G.; Krishnan, R.M.; Beelen, R.; Peters, A. et al. (2013). Long-term air pollution exposure and cardio-respiratory mortality: A review. Environ. Health 12.

9. Pedersen, M.; Giorgis-Allemand, L.; Bernard, C.; Aguilera, I. et al. (2013). Ambient air pollution and low birthweight: A European cohort study (ESCAPE). Lancet Resp. Med.1, 695–704.

10. Stafoggia, M.; Cesaroni, G.; Peters, A.; Andersen, Z.J. et al. (2014). Long-term exposure to ambient air pollution and incidence of cerebrovascular events: Results from 11 European cohorts within the ESCAPE project. Environ. Health Perspect. 122, 919–925.

11. Jacquemin, B.; Sunyer, J.; Forsberg, B.; Aguilera, I. et al.  (2009). Home outdoor NO₂ and new onset of self-reported asthma in adults. Epidemiology 20, 119–126.

12. Hamer, M., Yoichi, C. (2008). Active commuting and cardiovascular risk: A meta-analytic review. Preventive Medicine 46:9-13.

13. Swinburn, B., Sacks, G., Hall, K.D., McPherson, K., et al. (2011). The global obesity pandemic: shaped by global drivers and local environments. Lancet 378:804–14.

14. Lindsay, G., Macmillan, A., Woodward, A. (2011). Moving urban trips from cars to bicycles: impact on health and emissions. Australian and New Zealand Journal of Public Health, 35:54–60.

15.  Genter, J.A., Donovan, S., Petrenas, B., Badland, H. (2008). Valuing the health benefits of active transport modes. NZ Transport Agency Research Report 359.  72 pp.

16. Litman, T. (2010). Evaluating Public Transportation Health Benefits. Victoria Transport Policy Institute. Available online: http://www.apta.com/resources/reportsandpublications/Documents/APTA_Health_Benefits_Litman.pdf  (accessed 10 May 2017).

17. Rissel, C., Curac, N., Greenaway, M., Bauman, A. (2012). Physical activity associated with public transport use—a review and modelling of potential benefits. Int J Environ Res Public Health 9(7): 2454-78.

18. van Kampen, E.; Babisch, W. (2012). The quantitative relationship between road traffic noise and hypertension: A meta-analysis. J. Hypertens. 30, 1075–1086.

19. Babisch, W. (2008). Road traffic noise and cardiovascular risk. Noise & Health 10(38): 27–33.

20. WHO. (2011). Burden of disease from environmental noise: Quantification of healthy life years lost in Europe. Geneva: World Health Organization. 

21. Tiesler, C.M., Birk, M., Thiering, E., Kohlböck, G., et al. (2013). Exposure to road traffic noise and children’s behavioural  problems and sleep  disturbance: results from the GINIplus and LISAplus studies. Environ Res.  123: 1–8. 

22. European Commission. (2015). Science for Environment Policy Thematic Issue: Noise impacts on health (Issue 47). European Union: Bristol.

23. Mindell, J.S., Watkins, S.J, Cohen, J.M. (2011). Health on the Move 2. Stockport: Transport and Health Study group. 

24. WHO. (2012).  Environmental health inequalities in Europe. Copenhagen: World Health Organization.

25. Briggs, D., Mason, K., Borman, B. (2016). Rapid assessment of environmental health impacts for policy support: The example of road transport in New Zealand.  International Journal of Environmental Research and Public Health 13: 61.

26. NZCPHM. (2013). Transport: New Zealand College of Public Health Medicine Policy Statement.

27. Grundy, C. (2009). Effect of 20 mph traffic speed zones on road injuries in London, 1986–2006: controlled interrupted time series analysis.  British Medical Journal 339:b4469.