A new study from the AAA Foundation for Traffic Safety examines the relationship between using a cell phone while driving and the risk of being involved in a crash by comparing cell phone use immediately prior to crashes versus during ordinary driving.
A key finding — that visual-manual tasks, particularly texting, are associated with significantly increased crash risk — reflects that of several previous studies.
The study, “Crash Risk of Cell Phone Use While Driving: A Case-Crossover Analysis of Naturalistic Driving Data,” identifies association of crashes with a variety of driver cell phone behavior. Odds ratios were calculated for overall cell phone use, conversation, overall visual-manual cell phone use, and several specific visual manual tasks including texting, dialing, browsing, an reaching for or answering the phone.
The study found that visual-manual interaction with cell phones while driving — particularly text messaging — nearly doubled the incidence of crash involvement relative to driving without performing any observable secondary tasks. Moreover, driver texting was prevalent — 42 of 65 crashes that involved any form of visual-manual interaction with cell phones involved texting.
Associations between visual-manual cell phone interaction and crash risk tended to be stronger in free-flow traffic and in types of crashes in which the subject driver played a clear role, such as rear-end and road-departure crashes. Estimated risks were lower than in most past studies that examined risk of involvement in real-world crashes, likely due to the greater control for individual and situational risk factors in the current study.
The study draws on data from the Second Strategic Highway Research Program Naturalistic Driving Study.
It includes data from a sample of 3,593 drivers whose driving behavior was monitored over a period of 38 months (October 2010 to December 2013) using in-vehicle video and other data collection equipment. The driver sample is comprised of an equal mix of male and female drivers from various age groups and socioeconomic strata. Data were collected across six study sites in the U.S. to ensure geographical diversity.
Driver cell phone use and crash incidence was quantified using a case-crossover study design in which a driver’s cell phone use in the six seconds immediately prior to the crash was compared with the same driver’s cell phone use in up to four six-second segments of ordinary driving under similar conditions (time of day, weather, locality, lighting and speed) within the three months prior to the crash. The study sample included 566 severe, moderate and minor crashes matched to 1,749 segments of ordinary driving.
Read the full report here.
Editor's note: Marianne Matthews is a contributor to AutomotiveFleet.com.