Exposure-Based, 'Like-for-Like' Assessment of Road Safety by Travel Mode Using Routine Health Data

Background: Official reports on modal risk have not chosen appropriate numerators and denominators to enable like-for-like comparisons. We report age- and sex-specific deaths and injury rates from equivalent incidents in England by travel mode, distance travelled and time spent travelling. Methods: Hospital admissions and deaths in England 2007-2009 were obtained for relevant ICD-10 external codes for pedestrians, cyclists, and car/van drivers, by age-group and sex. Distance travelled by age- group, sex and mode in England (National Travel Survey 2007-2009 data) was converted to time spent travelling using mean trip speeds. Fatality rates were compared with age- specific Netherlands data. Results: All-age fatalities per million hours' use (f/mhu) varied over the same factor-of-three range for both sexes (0.15-0.45 f/mhu by mode for men, 0.09-0.31 f/mhu for women). Risks were similar for men aged 21-49 y for all three modes and for female pedestrians and drivers aged 21-69 y. Most at risk were: males 17-20 y (1.3 f/mhu (95% CI 1.2-1.4)) for driving; males 70+ (2.2 f/mhu(1.6-3.0)) for cycling; and females 70+ (0.95 f/mhu (0.86-1.1)) for pedestrians. In general, fatality rates were substantially higher among males than females. Risks per hour for male drivers,30 y were similar or higher than for male cyclists; for males aged 17-20 y, the risk was higher for drivers (33/Bn km (30-36), 1.3 f/mhu (1.2-1.4)) than cyclists (20/Bn km (10-37), 0.24 f/mhu (0.12-0.45)) whether using distance or time. Similar age patterns occurred for cyclists and drivers in the Netherlands. Age-sex patterns for injuries resulting in hospital admission were similar for cyclists and pedestrians but lower for drivers. Conclusions: When all relevant ICD-10 codes are used, fatalities by time spent travelling vary within similar ranges for walking, cycling and driving. Risks for drivers were highest in youth and fell with age, while for pedestrians and cyclists, risks increased with age. For the young, especially males, cycling is safer than driving. Citation: Mindell JS, Leslie D, Wardlaw M (2012) Exposure-Based, 'Like-for-Like' Assessment of Road Safety by Travel Mode Using Routine Health Data. PLoS ONE 7(12): e50606. doi: 10.1371/journal.pone.0050606