How Risky is It? An assessment of the relative risk of engaging in potentially

unsafe driving behaviors

AAA Foundation for Traffic Safety

• Established in 1947

• 501 (c)(3) Not-For-Profit

• Research affiliate of AAA/CAA

• North American Focus

Mission

• Identify traffic safety problems

• Foster research that seeks solutions

• Disseminate information and educational materials

Funded through the generosity

of

and its members

Published December 2006Published December 2006

Prepared by:Prepared by:

Virginia Tech Virginia Tech Transportation Transportation

InstituteInstitute

Available online at:Available online at:

www.aaafoundation.org

Purpose of Study

• Perform additional analysis of data collected under previous 100-Car Naturalistic Driving Study to investigate impacts of various behaviors on crash risk

• Behaviors studied:– speeding– drowsy driving– aggressive driving– distracted driving

The 100-Car Naturalistic Driving Study

• $3 Million study sponsored by National Highway Traffic Safety Administration, Virginia DOT, and Virginia Tech

• Conducted by Virginia Tech Transportation Institute

• Collected unprecedented level of driving data pre-crash and normal driving behavior

100-Car Study “Naturalistic” Approach

• Used in-vehicle camera and custom-built advanced “black box” to monitor drivers– 100 equipped vehicles– 12-13 months of data collection, no “experimenter”

present– Subjects not “coached,” instructed to drive “as usual”– Instrumentation was unobtrusive and inconspicuous to

other drivers, but not invisible– NHTSA-sponsored work indicates subjects’ driving

was uninfluenced by in-vehicle monitoring after the first few hours (out of 12-13 months)

100-Car Study Equipment

Driver Face Camera

Forward Road Camera

“Black Box”

100-Car Study Camera Views

100-Car Study Camera Views

100-Car Study Participants

• 109 primary drivers– Ages 18-68– 60% male, 40% female– Recruited in Washington DC & Northern VA– Range from “very safe” to “very unsafe”– Wide range of driving mileage– Drove on all road classes– Mostly urban & suburban driving, some rural– Drove sedans and SUVs– Also 132 secondary drivers

100-Car Study Database Statistics

Captured data on:

• 42,300 hours and ~2 million miles of driving• 82 Crashes and collisions

– Defined as any contact between the subject vehicle and another vehicle, object, pedestrian, cyclist, or animal

• 761 Near crashes – Defined as a conflict situation requiring a rapid, severe evasive

maneuver to avoid a crash

• 8,295 Incidents– Conflict requiring an evasive maneuver, but of less magnitude

than a near crash

• 20,000 normal baseline driving epochs– To compare driver behavior during normal driving to behavior

leading up to crashes, near crashes, and incidents

This Study

• Investigated the frequency with which drivers engage in various potentially risky behaviors during ordinary driving and immediately prior to crashes, near-crashes, and incidents

• Analyzed the impacts of various behaviors on the risk of being involved in a crash or near-crash

Results – Frequency of Behaviors

BehaviorCrashes & Near-crashes

Baseline epochs

Inappropriate Speed

(faster than surrounding traffic)8.8% 2.6%

Drowsy 12.5% 4.3%

Aggressive Driving 17.6% 3.0%

Eyes Off Road

(longer than 2 seconds)24.5% 14.1%

Results – Risk of Crash or Near Crash

Behavior Odds Ratio

Inappropriate Speed

(faster than surrounding traffic)

2.9 (95% CI: 1.7 – 4.8)

Drowsy 2.9 (95% CI: 2.0 – 4.3)

Aggressive Driving 2.1 (95% CI: 1.3 – 3.4)

Eyes Off Road

(longer than 2 seconds)1.9 (95% CI: 1.4 – 2.5)

Note: Odds of crash or near-crash with behavior present vs. absent; computed using logistic regression to control for other behaviors; odds ratio > 1 indicates increased risk

Conclusions

• The odds of being involved in a crash are nearly tripled when driving while drowsy or driving faster than surrounding traffic.

• The odds of being involved in a crash are approximately doubled when driving aggressively or when looking away from the road for longer than 2 seconds.

For more information on the 100-Car Study, please go to:

http://www.vtti.vt.edu and click on 100-Car Study

Or go to:

http://www-nrd.nhtsa.dot.gov/departments/nrd-13/newDriverDistraction.html

For more information about this study sponsored by the AAA

Foundation for Traffic Safety,

please go to:

www.aaafoundation.org

The AAA Foundation for Traffic Safety is a 501(c)(3) public charity located in Washington, DC that is dedicated to saving lives and reducing injuries.

It is supported by donations from AAA/CAA Clubs, AAA/CAA members, and other organizations associated with AAA/CAA.