Analysis of Naturalistic Driving Study Data: Safer Glances, Driver Inattention, and Crash Risk

Victor, T., Bargman, J., Boda, C. N., Dozza, M., Engstrom, J., Flannagan, C., Lee, J. D., and Markkula, G.
Transportation Research Board

This analysis of naturalistic driving data from the SHRP2 project examined the relationship between driver inattention and crash risk in lead-vehicle pre-crash scenarios. More specifically, the objective was to capture inattention performance measures associated with pre-crash situations. The sample size for this study included 46 crash events, 211 near-crash events, 257 matched baseline events, and 260 random baseline events. These events were selected in relation to five scenarios because of their high ranking in crash frequency, the number of functional years lost, and economic costs, and their role in driver inattention. These scenarios included:

  • following vehicle making a maneuver
  • lead vehicle accelerating
  • lead vehicle moving at lower constant speed
  • lead vehicle decelerating ; and,
  • lead vehicle stopped.

Researchers investigated the impact of talking on a cell phone on crash risk in relation to the length of time drivers had their eyes off of the road while driving. A majority of eye glances off of the road were due to the cell phone itself and started with pushing a button to accept the call.
Results revealed that talking on a cell phone increased crash/near-crash risk significantly in comparison to drivers that did not engage in a phone conversation. In addition, data showed that eye glances off the road posed a higher crash risk than performing secondary tasks (i.e., cell phone use, eating). Results also provided insight into how much time a driver could “look away” before a rear-end crash becomes likely, and revealed that visually demanding tasks were associated with the highest risk. In particular, texting had the highest odds ratio suggesting a greater crash and near-crash risk. Authors concluded that the design of interfaces should minimize the need for drivers to take their eyes off the road, particularly in relation to portable electronic devices.

Victor, T., Dozza, M., Bärgman, J., Boda, C. N., Engström, J., Flannagan, C., & Markkula, G. (2015). Analysis of naturalistic driving study data: Safer glances, driver inattention, and crash risk (No. SHRP 2 Report S2-S08A-RW-1).