Driver Distraction: Results from Naturalistic Teenage Driving Studies

Charlie Klauer, Ph. D.

Research Scientist Group Lead: Teen Risk and Injury Prevention Center for Vulnerable Road Users Virginia Tech Transportation Institute

Introduction

• Driver distraction, defined here as engaging in a secondary task or activity that is not central to the primary task of driving, has been shown to be a contributing factor for many crashes.

• Secondary tasks and other activities in which drivers choose to engage while driving is also known to be highly varied, including very complex activities (e.g., text messaging on a cellular device) to very simple activities (e.g., selecting a radio preset).

A New Method of Study: Large-Scale Naturalistic Driving

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40 to 100 drivers

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No instructions

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12 to 18 mos.

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10,000’s of hours

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2 MVMT

Driving Safety Research Approaches

• Epidemiological Studies • PARs • Simulation • Test Track • Lab Experiment NDS • Missing Piece?

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Naturalistic Data Collection Approach

Highly capable instrumentation (well beyond EDRs)

• Multiple channels of digital, compressed video • Multiple radar sensors front, rear and/or side • Machine vision-based lane tracker • Many other sensors: GPS, glare, RF, acceleration, yaw rate, controls, etc.

• Cell phone, wireless internet, or hardwire download • Ties into vehicle networks to obtain other information

Limitations…

• Have not yet captured a large number of crash events • To overcome this limitation several studies have utilized “near crashes” in combination with crashes. • Near crashes, in this case, are defined as having all of the elements of a crash with the exception that the driver implements a successful evasive maneuver. • The 100 Car Study showed that near crash involvement is correlated with crash involvement across differing drivers • There is a growing body of evidence that combining crash and near crash events provides a valid measure of overall crash risk.

Results: Driver inattention is a key contributing factor in crashes for both truck and light vehicles.

• The largest single contributing factor is looking away from the roadway just prior to an unexpected event or condition. This accounts for somewhere between 70% and 90% of unsafe events.

• Engaging in activities that are unrelated to driving (i.e., “secondary tasks”) and external distractions account for most of the inattention related risk. – High Risk: Looking away many times and/or long periods – Includes: Cell phone dialing, text messaging, Ipod/MP3 manipulation, and internet interaction. – Much less risk: Eating/drinking, talking to passengers, simple radio functions, and even talking on a cell phone. • Teens are four times more likely to be involved in a near crash or crash while performing a secondary task than their adult counterparts.

Analysis Approach

• Data analyses were conducted utilizing the “100 car” and heavy truck naturalistic driving databases.

• These data were specifically coded for the purpose of assessing secondary task distraction. • From these data, an “event” database of crashes and near crashes was created with – 830 crashes, minor collisions and near crashes (100 Car) – 118 crashes, minor collisions, and near crashes (34 Truck) • These data were also used to develop a “non event” or baseline database to assess exposure.

• These results have significant design implications for driver-vehicle interfaces – Cognitive-only, or auditory-voice secondary task interfaces will generally be less risky than visuo manual secondary tasks. – The tasks with the highest crash risk are those that require multiple glances away from the road.

Hand-held is substantially riskier than “true” hands-free.

• Operating a complex hand-held device is significantly more risky than a hands-free counterpart.

• Dialing and answering a hand-held phone were both higher risk tasks, even in comparison to the often longer task of talking on a hand held phone.

• Greatest proportion of risk does not come from the conversation or act of holding a phone to one’s ear, it comes from the complex task components of dialing, answering, texting, etc. that require multiple glances away from the roadway.

Cognitive versus Visual Distraction

• Conversation may be distracting but it does not translate into crashes/near crashes – True for naturalistic data and crash database data.

• Visual distraction, eyes off forward roadway increases crash/near crash risk – True for naturalistic data and controlled experiments.

Future NDS

• SHRP 2 – ~3000 participants • Supervised Practice Driving Study – 90 teenaged drivers • MSF 100 Motorcycle Study