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New VTTI study results continue to highlight the dangers of distracted driving

   

Greg Fitch A new VTTI study shows an increased risk of getting into a crash when engaging in visual-manual subtasks (such as reaching for a phone, dialing and texting) associated with the use of hand-held phones and other portable devices.

Recently released results from a new Virginia Tech Transportation Institute (VTTI) naturalistic driving study continue to show that distracted driving is a tangible threat. The study, entitled The Impact of Hand-Held and Hands-Free Cell Phone Use on Driving Performance and Safety Critical Event Risk, shows that engaging in visual-manual subtasks (such as reaching for a phone, dialing and texting) associated with the use of hand-held phones and other portable devices increased the risk of getting into a crash by three times. The data were collected by VTTI and Westat. The study, which was conducted under a separate contract from the National Highway Traffic Safety Administration (NHTSA), found:

  • Text messaging, browsing and dialing resulted in the longest duration of drivers taking their eyes off the road.
  • Text messaging increased the risk of a crash or near-crash by two times and resulted in drivers taking their eyes off the road for an average of 23 seconds total.
  • Activities performed when completing a phone call (reaching for a phone, looking up a contact and dialing the number) increased crash risk by three times.
  • There is no direct increased crash risk from the specific act of talking on a cell phone. However, visual-manual tasks (locating the phone, looking at the phone and touching the phone) are always involved when using a hand-held cell phone. This makes the overall use of a hand-held cell phone riskier when driving.
  • Even portable hands-free and vehicle-integrated hands-free cell phone use involved visual-manual tasks at least half of the time, which is associated with a greater crash risk.

Additional details of safety-critical event risks related to cell phone use are included in the following table. To learn more about the VTTI study, view the full report here.


Safety-critical Event Risk Associated with Cell Phone Use

Subtask
Rate Ratio
95% Confidence Interval*
Overall Cell Phone Use1.320.96 - 1.81
Visual-manual Subtask (such as looking at or touching a cell phone, reaching for the phone, dialing, texting, etc.)2.93**1.90­­ - 4.51

Call-related Visual-manual Subtask

3.34**1.76 - 6.35

Text-related Visual-manual Subtask

2.12**1.14 - 3.96

Talking/Listening

0.840.55 - 1.29

Talking/Listening (Hand-held Phone)

0.840.47 - 1.53

Talking/Listening (Portable Hands-free, such as a Bluetooth earpiece)

1.190.55 - 2.57

Talking/Listening (Integrated Hands-free, which is built into the vehicle navigation system)

0.610.27 - 1.41
Hand-held Cell Phone Use1.73**1.20­­ - 2.49
Portable Hands-free Cell Phone Use1.060.49 - 2.30
Integrated Hands-free Cell Phone Use0.570.25 - 1.31

* Indicates 95% confidence that the actual safety-critical event risk falls within the lower and upper limits

** Indicates a difference at the .05 level of significance


Source: Fitch, G. A., Soccolich, S. A., Guo, F., McClafferty, J., Fang, Y., Olson, R. L., Perez, M. A., Hanowski, R. J., Hankey, J. M., & Dingus, T. A. (2013, April). The impact of hand-held and hands-free cell phone use on driving performance and safety-critical event risk. (Report No. DOT HS 811 757). Washington, DC: National Highway Traffic Safety Administration


The latest results from a Virginia Tech Transportation Institute (VTTI) naturalistic driving study show that distracted driving continues to be a tangible threat.