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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
• 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
40 to 100 drivers
12 to 18 mos.
10,000’s of hours
Driving Safety Research Approaches
• Epidemiological Studies • PARs • Simulation • Test Track • Lab Experiment NDS • Missing Piece?
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
• 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.
• 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.
• SHRP 2 – ~3000 participants • Supervised Practice Driving Study – 90 teenaged drivers • MSF 100 Motorcycle Study