Road cyclist fatalities are declining overall, but increasing for adults (because they're biking more)

A recent CDC report highlights what anyone who looks at NHTSA reports of FARS data already knew - that while total motor-vehicle associated bicycle fatalities are on a steep decline, that is almost entirely driven by a reduction in youth fatalities. Meanwhile adult cyclist fatalities are increasing*.

During 1975–2012, the cyclist mortality rate among children aged <15 years declined 92%.

Mortality rates for adults aged 35–74 years increased significantly during the study period. The largest increase was among adults aged 35–54 years, with the mortality rate increasing nearly threefold, from 0.11 to 0.31 per 100,000.

And the rate for men has increased even more

The overall mortality rate for males was six times greater than the overall mortality rate for females. In 2012, males accounted for 87% of total bicycle deaths in the United States. This proportion increased over the 38-year study period, from 79% in 1977 to a peak of 90% in 2001.

A three-fold increase in the mortality rate of adults isn't that surprising considering that "the share of total household trips taken by bicycle has doubled over the last 35 years." Since children are biking less, adults must be biking more. If adult exposure to road cycling has increased by 3 or more time as much, it would entirely explain the uptick. And the CDC says as much

Although many factors could influence cyclist mortality trends, the observed trends by age and sex during the study period likely reflect the changing prevalence of cycling among those groups.

Thus, the decline in bicyclist mortality among children might be attributable to fewer child bicycle trips rather than a result of safer road conditions. Increased use of helmets among children might also have contributed to reduced child bicyclist mortality over the study period.

While the report doesn't deal much with the reasons for these trends, or how to make cycling safer, it does have some suggestions.

Many factors likely contribute to trends in bicycling fatalities, including prevalence of bicycling, road design and engineering, traffic law enforcement, driver and bicyclist behavior, helmet use, and traffic volume.

Several countries and some U.S. cities have higher bicycle use and lower mortality rates than the United States overall. Many have implemented multifaceted, integrated approaches to bicycling that address safety while also promoting cycling. Such approaches often include extensive bicycle infrastructure (e.g., physically separated bike lanes), traffic calming measures (e.g., speed humps), legal interventions (e.g., lowered speed limits), travel programs (e.g., safe routes to school), and education to encourage safe bicyclist and motorist behavior (1). Other strategies that can reduce fatalities include helmet laws and improved conspicuity of cyclists via lights and bright or reflective clothing.

A possible take-away from this is that urban areas might be much safer for cyclists, and in fact when compared to other "states" (Except Hawaii and Alaska for which insufficient data exists) DC has the highest "bike commute rate/mortality rate" ratio in the country (which means DC is much safer than the national average). Arkansas has the highest lowest. In fact, people in DC are 26 times more likely to bike commute than people in Arkansas, but still only about 70% as likely to die in a bicycle-car fatality.** The full rankings are below, and more on this tomorrow.

*fatalities are based on FARS data, which has some limitations. Namely, it only counts deaths involving a motor vehicle and only on some roads (not parking lots) and only by some law enforcement agencies. It doesn't appear that federal law enforcement agencies report to the system

**Admittedly, the mortality rate is a measure of cyclists deaths regardless of where they reside, and comute rate is a measure of how residents get to work, so for DC - where many people on bikes are not residents - this skews the numbers. But it probably UNDER represents the exposure in DC, while accurately representing the relative risk of fatalities. Also note that commute rate may not be a good way to compare exposure for other reasons.

Comments

[charlie]

I understand what you are saying here, but it is confusing? Arkansas is the lowest?

"DC has the highest "bike commute rate/mortality rate" ratio in the country (which means DC is much safer than the national average). Arkansas has the highest. I"

"*Admittedly, the mortality rate is a measure of cyclists deaths regardless of where they reside, and comute rate is a measure of how residents get to work, so for DC - where many people on bikes are not residents - this skews the numbers"

Is this true - that "many" people on bikes are not residents? Very true for Bikeshare, obviously, although no deaths. and not many commuters there compared to tourists.

And again a useful reminder that in the metro area, safety/bike rights is not a huge priority in the district. Creating infrastructure is. Might be more critical in VA and MD.

And building safe infrastructure -- more like the 15th, less like the L and M with their turns.

[JimT]

The final column needs three more zeroes. Although I think it would be more intuitive to take the reciprocal of that ratio, which would give you fatalities per bike commuter.

[washcycle]

Is this true - that "many" people on bikes are not residents?

In DC it is. It was one of the questions on the survey done by DDOT in 2003 as part of the 2005 Master Plan process. The results of that question are not in the report, but I seem to recall that nearly half of all cyclists in DC lived outside of DC, and that didn't include tourists.

I think safety is a "huge" priority (relative to other areas) in the District, which is why there has been so much infrastructure built, a Vision Zero commitment and the recent Bicycle and Pedestrian Safety Working Group.

[washcycle]

JimT, adding three zeroes wouldn't really change anything, but it would make it harder to read. 0.026/0.14 is 0.1857 (DC's ratio). I multiplied it by 100 to make it easier to read.