What Drives Traffic Fatality Risks?
| David Gerard |
Does the inclement weather have you worried about sliding off the road to an icy death? If so, I’ve got some good news for you. On a per-mile driven basis (or per-trip or per-minute traveled), winter is actually the least likely time to get killed behind the wheel. Summer drivers have a risk of 1.24 fatalities per 100 million miles driven compared with 1.01 during the winter. For males behind the wheel of an SUV, those summer and winter numbers are 1.39 and 0.87, respectively.
That’s what we discovered when we teamed with the AAA Foundation for Traffic Safety to develop TrafficSTATS — an interactive website that merges traffic fatality and personal travel information to generate risk estimates. The site generates risk estimates for combinations of age, day of week, month of the year, gender, hour of the day, drivers, passengers, and vehicle types. Did you know that a man behind the wheel is 80% more likely to get killed than a woman? Or that 16-20 year-old drivers have about the same fatality risk as 75-84 year-olds?
Although our estimates are a simple ratio generated by merging federal fatalities and personal travel behavior databases, we believe that our risk estimates frame risk in a far superior fashion than using fatalities or other risk proxies. For example, one common metric is deaths per registered vehicle. By this measure it looks like SUVs are more dangerous than cars. Adjusting for the fact that SUVs are driven more miles and carry more passengers than cars do provides a much different picture — SUVs are a lot safer (0.85 SUV and 1.02 passenger car fatalities per 100 million passenger miles traveled). Not only that, we also found that even the rollover risk for SUVs and cars are virtually the same for 25-50 year old drivers, and the divergence in rollover risks stems predominantly from high fatality risks for young and old drivers (PowerPoint and paper).
One caveat, the site was developed with MS tools and works best in Internet Explorer. What was that post about path dependence? Aaack.