Health burden of road transport

This section estimates the health burden of road transport in New Zealand, based on a recent study carried out by our team (Briggs et al, 2016). 

Road transport accounted for an estimated 650 deaths in 2012

These deaths were caused through four pathways associated with road transport (Figure 1): injuries from road traffic incidents, air pollution (in the form of particulate matter), nitrogen dioxide exposure, and traffic noise pollution.

Figure 1: Estimated deaths attributable to road transport, 2012

Of these causes, the effect of traffic noise on health is less well understood. However, there is a growing body of evidence that exposure to noise pollution may have a range of effects ranging from reduced sleep and raised stress levels, to increased blood pressure and higher risk of strokes, heart disease and hypertensive disorders.

Cars are responsible for half of all transport-related deaths

Cars were estimated to be responsible for about 52% of deaths attributable to road transport in 2012.  Heavy goods vehicles (representing just 6% of vehicle kilometres travelled, VKT) accounted for 21% of deaths. Motorcycles (1% of VKT) were implicated in nearly 8% of deaths. For more information, see Table 1.

Table 1: Approximate allocation of responsibility for deaths by transport mode, 2012

In terms of deaths per kilometers travelled, motorcycles contributed to deaths at a much higher rate than other transport modes:

  • Motorcycles: 127.5 deaths per billion VKT
  • Heavy Goods Vehicles: 51.5 deaths per billion VKT
  • Buses: 20.0 deaths per billion VKT
  • Light Goods Vehicles: 19.8 deaths per billion VKT
  • Cars: 10.7 deaths per billion VKT

Positive health outcomes of transport

Not all health outcomes associated with transport are negative. In 2012, an estimated 40 deaths were avoided through engaging in active modes transport, via the health benefits associated with increased physical activity. The majority (30 out of 40) of these deaths are estimated to be the result of avoided cases of ischemic heart disease. Use of active transport is estimated to be responsible for saving 1,429 Years of Life Loss (YLLs), or 1,874 Disability-Adjusted Life Years (DALYs).



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,2016; 13(1): 61.


An integrated environmental health impact assessment of road transport in New Zealand was carried out, using a rapid assessment. The disease and injury burden was assessed from traffic-related accidents, air pollution, noise and physical (in)activity, and impacts attributed back to modal source. 

In total, road transport was found to be responsible for 650 deaths in 2012 (2.1% of annual mortality): 308 from traffic accidents, 283 as a result of air pollution, and 59 from noise. Together with morbidity, these represent a total burden of disease of 26,610 disability-adjusted life years (DALYs). An estimated 40 deaths and 1,874 DALYs were avoided through active transport.

Cars are responsible for about 52% of attributable deaths, but heavy good vehicles (6% of vehicle kilometres travelled, VKT) accounted for 21% of deaths. Motorcycles (1 percent of VKT) are implicated in nearly 8% of deaths.

Overall impacts of traffic-related air pollution and noise are low compared to other developed countries, but road accident rates are high.

Results highlight the need for policies targeted at road accidents, and especially at heavy good vehicles and motorcycles, along with more general action to reduce the reliance on private road transport. The study also provides a framework for national indicator development.

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