Studies on the road-safety impact of large cars
Comments Off on Studies on the road-safety impact of large carsRecently published research from separate studies in Europe and the US quantifies the dangers that ever-larger cars present to pedestrians and other vulnerable road users, as well as the excessive strain they place on space and resources.
The European situation
European advocacy groups Transport & Environment (T&E) and Clean Cities Campaign published their study Ever-bigger? Car size at a crossroads, which examines the various impacts of car heights and widths expanding year-on-year, and outlines potential solutions to the problem.
Their report finds that, each year, the average length of new cars in Europe is increasing by 1.2 cm, and the average total height, bonnet height and width all increasing by 0.5 cm. The higher bonnet height of larger cars is particularly hazardous for vulnerable road users: separate research has shown that adult pedestrians struck by an SUV are 44% more likely to be killed than if by a smaller car, with the likelihood rising to 82% higher for children.
The T&E/Clean Cities report advises that action is taken to commence what they term “right-sizing” of cars – in effect, reversing the trend of increasing car dimensions, to bring them back to levels of cars produced in the 2010-2015 period.
If the trend of increasing car size were to continue unchecked, on average car bonnets will reach a height of 92 cm by 2040. This compares to 77 cm in 2010, and the current average of 84 cm. Right-sizing would bring the height back to 77 cm.
The report’s modelling shows that:
- Under current trends, 40% more children walking would be killed a year in car crashes by 2040 compared to the Right-sizing scenario (EU and UK). The gap rises through the 2030s, and in 2040, the ever-bigger trend would see 39 children (aged up to 14) killed, compared to 28 under a right-sizing scenario.
- For vulnerable road users (pedestrians, cyclists, motorcyclists and moped riders of all age groups) current trends would bring 400 additional deaths annually by 2040 compared to a more balanced scenario (14% higher).
Increasing car lengths also pose a problem, placing pressure on cities’ parking space, with the loss of 8.5% to 14% of on-street parking spaces predicted by 2040 if the trend continues. Larger cars also place pressure on road infrastructure, and demand for electricity and oil.
The report outlines key policy approaches to address the car-spreading problem:
- Cap bonnet height in new cars at 85 cm, and limit width to 192 cm (EU level, and UK)
- Add vehicle dimensions to vehicle registration certificates (national governments / EU)
- Ensure that regulatory advantages only go to small electric cars (not longer than 4.2 metres) in revising car CO2 law (EU)
- Rate the vision of children from the driver’s seat of new cars (Euro NCAP), and apply a Child Vision Standard in law (EU, and UK)
- Vary car taxes and parking charges by dimensions (national governments, and cities)
Figures from the US
An investigation by the New York Times looks at the shift in the US towards taller and heavier SUVs and trucks, finding that they are responsible for an estimated 200-400 additional pedestrian deaths per year.
It finds that each one-inch (2.54 cm) increase in bonnet height is associated with a 2.8% increased odds of a pedestrian death. 39% of current US vehicles are tall enough to knock an average-height adult male to the pavement rather than carry him onto the bonnet, an increase of 29% from 2002. Blind zones in popular pick-ups have also grown rapidly over the last two decades.

