Database improvements for motor vehicle/bicycle crash analysis

Abstract

Background: Bicycling is healthy but needs to be safer for more to bike. Police crash templates are designed for reporting crashes between motor vehicles, but not between vehicles/bicycles. If written/drawn bicycle-crash-scene details exist, these are not entered into spreadsheets.

Objective: To assess which bicycle-crash-scene data might be added to spreadsheets for analysis.

Methods: Police crash templates from 50 states were analysed. Reports for 3350 motor vehicle/bicycle crashes (2011) were obtained for the New York City area and 300 cases selected (with drawings and on roads with sharrows, bike lanes, cycle tracks and no bike provisions). Crashes were redrawn and new bicycle-crash-scene details were coded and entered into the existing spreadsheet. The association between severity of injuries and bicycle-crash-scene codes was evaluated using multiple logistic regression.

Results: Police templates only consistently include pedal-cyclist and helmet. Bicycle-crash-scene coded variables for templates could include: 4 bicycle environments, 18 vehicle impact-points (opened-doors and mirrors), 4 bicycle impact-points, motor vehicle/bicycle crash patterns, in/out of the bicycle environment and bike/relevant motor vehicle categories. A test of including these variables suggested that, with bicyclists who had minor injuries as the control group, bicyclists on roads with bike lanes riding outside the lane had lower likelihood of severe injuries (OR, 0.40, 95% CI 0.16 to 0.98) compared with bicyclists riding on roads without bicycle facilities.

Conclusions: Police templates should include additional bicycle-crash-scene codes for entry into spreadsheets. Crash analysis, including with big data, could then be conducted on bicycle environments, motor vehicle potential impact points/doors/mirrors, bicycle potential impact points, motor vehicle characteristics, location and injury.

Figure 1

Bicycle and vehicle points of impact coding.

Figure 2

Drawing of vehicle/bicycle crash. The diagram shows a one way street north with three lanes of traffic (up arrow symbol), a bus lane, a cycle track, and on both sides parallel parked cars (□). The diagram also shows a one way street east with one lane of traffic (right pointing arrow symbol), a bike lane, and parallel parked cars on both sides (□). The vehicle is drawn as a rectangle and the bicycle crashed into the opened back door on the driver's side.

Figure 3

Crash patterns coding (turn/impact).