Trends in Bicyclist Crash Injuries and Government Spending on Active Transportation Infrastructure in California, 2005-2011

Background: There has been an increasing focus on bicyclist crashes, injuries, and fatalities in the empirical literature and news media. The purpose of this study is to examine trends in government spending on active transit facilities and injuries from bicyclist crashes.

Methods: We examined 7 years of health services and government expenditure data in California. The outcome variables were visits to the emergency department (ED) and inpatient admissions specifically related to injuries from bicyclist crashes. Injuries were adjusted for the number of weekly bicycle trips per 100 people to account for exposure to crash risk. The main predictor variable was the cumulative money spent per capita by the state of California on active transit infrastructure. 

Results: Cumulative spending per capita on active transit infrastructure increased from $0.83 in 2005 to $3.95 in 2011. This spending was positively associated with the number of bicycle trips per 100 people, which increased from 22.6 to 60.9. Injuries per bicycle trip decreased over the study period from 8.2 visits to the ED in 2005 to 3.9 ED visits per 100,000 bike trips in 2011. This finding was also found for inpatient admissions, which decreased from 0.75 in 2005 to 0.33 per 100,000 bike trips in 2011.

Conclusions: Total government spending on active transportation infrastructure was associated with recent trends in more bicycle trips and lower injury rates from bicycle crashes. More research is needed, but our preliminary evidence seems to support the hypothesis that increasing infrastructure for active transportation reduces injuries associated with crashes.