October 2016

  1. How frequently do drivers talk on the phone or text behind the wheel?

    A 2015 national observational survey found that 4 percent of drivers stopped at intersections were talking on hand-held phones at any moment during the day. National Highway Traffic Safety Administration. 2016. Driver electronic device use in 2015. Report no. DOT HS-812-326. Washington, DC: U.S. Department of Transportation.
    Combining this observational data with self-reported data on hand-held and hands-free phone use, the federal government estimates that 7 percent of drivers were having phone conversations during any moment of the day. This rate has declined 23 percent since 2013 after doubling between 2000 and 2005.

    Institute research examined the cellphone use of 105 Virginia drivers whose daily driving was monitored continuously for one year during 2003-04. Farmer, C.M.; Klauer, S.G.; McClafferty, J.A.; and Guo, F. 2015. Relationship of near-crash/crash risk to time spent on a cellphone while driving. Traffic Injury Prevention 16(8): 792-800. On average, drivers spent 7 percent of their driving time talking or listening to a cellphone. A naturalistic study of drivers in Michigan conducted during 2009-10 also estimated that drivers talked on cellphones about 7 percent of the time, on average. Funkhouser, D. and Sayer, J. 2012. Naturalistic census of cell phone use. Transportation Research Record 2321:1-6.

    National observation surveys indicate the rate of drivers texting at any moment during the day is rising, especially among younger drivers. In 2015, 2.2 percent of all drivers and 4.9 percent of drivers estimated to be 16-24 years old were observed texting or otherwise manipulating hand-held devices. National Highway Traffic Safety Administration. 2016. Driver electronic device use in 2015. Report no. DOT HS-812-326. Washington, DC: U.S. Department of Transportation.
    That's a 267 percent increase from 0.6 percent in 2009 for all drivers and a 345 percent increase from 1.1 percent in 2009 for drivers 16-24 years old. In a 2015 national online survey, almost one-third of drivers reported sending a text message or e-mail while driving at least once in the past 30 days, and 42 percent said they had read a text or e-mail. AAA Foundation for Traffic Safety. 2016. 2015 traffic safety culture index. Washington, DC.

  2. Who is most likely to use a cellphone while driving?

    Younger drivers are more likely than older drivers to talk on phones and to text while driving.

    In a 2015 national online survey, about 77 percent of drivers 19-24 years old and 78 percent of drivers 25-39 years old said they had talked on a cellphone while driving in the past 30 days, but only 60 percent of drivers 60-74 years old and 42 percent of drivers 75 and older said the same. AAA Foundation for Traffic Safety. 2016. 2015 traffic safety culture index. Washington, DC. A larger proportion of 19-24 and 25-39-year-old drivers also said they had read or sent a text or e-mail while driving in the past 30 days compared with drivers 60 and older.

    In 2015, nearly 5 percent of drivers ages 16-24 and 4 percent of drivers ages 25-69 were observed talking on a hand-held cellphone while stopped at intersections during the daytime, compared with only 1 percent of drivers ages 70 and older. National Highway Traffic Safety Administration. 2016. Driver electronic device use in 2015. Report no. DOT HS-812-326. Washington, DC: U.S. Department of Transportation.
    About 5 percent of drivers ages 16-24 were observed manipulating a hand-held device, compared with only about 2 percent of drivers ages 25-69 and less than 1 percent of drivers ages 70 and older.

    A study that analyzed random samples of video recordings of daily driving by adults and newly licensed teenagers found no significant difference between the adult and teenage drivers in the percentage of cellphone conversations or dialing or reaching for phones. Klauer, S.G.; Guo, F.; Simons-Morton, B.G.; Ouimet, M.C.; Lee, S.E.; and Dingus, T.A. 2014. Distracted driving and risk of road crashes among novice and experienced drivers. New England Journal of Medicine 370:54-9.

    There is evidence that people who use cellphones more frequently while driving may be riskier drivers in other respects. In an Institute study of drivers who were continuously monitored for one year, the drivers who spent the greatest amount of their driving time interacting with a cellphone also had the highest rates of near-crashes and crashes. Farmer, C.M.; Klauer, S.G.; McClafferty, J.A.; and Guo, F. 2015. Relationship of near-crash/crash risk to time spent on a cellphone while driving. Traffic Injury Prevention 16(8): 792-800. In an on-road study, drivers who reported frequent cellphone use drove faster, changed lanes more often and made more hard braking maneuvers than drivers who said they rarely used cellphones while driving. Zhao, N.; Reimer, B.; Mehler, B.; D'Ambrosio, L. A.; and Coughlin, J. A. 2013. Self-reported and observed risky driving behaviors among frequent and infrequent cell phone users. Accident Analysis and Prevention 61:71-7.

     
  3. How does talking on a cellphone or texting while driving affect crash risk?

    There is growing evidence that talking on a cellphone increases crash risk, though it hasn't been firmly established.

    Two separate epidemiological studies linked talking on a cellphone to a fourfold increase in the likelihood of a crash resulting in injury to the driver McEvoy, S.P.; Stevenson, M.R.; McCartt, A.T.; Woodward, M.; Haworth, C.; Palamara, P.; and Cercarelli, R. 2005. Role of mobile phones in motor vehicle crashes resulting in hospital attendance: a case-crossover study. British Medical Journal 331(7514):428-30. and in the risk of a crash involving property damage but no injury. Redelmeier, D.A. and Tibshirani, R.J. 1997. Association between cellular-telephone calls and motor vehicle collisions. The New England Journal of Medicine 336:453-58.  

    Two recent studies, including one from the Institute, suggest estimates from these early epidemiological studies may be too high. Based on data from over 3,000 drivers who were continuously monitored for up to 3 years during 2010-13, the Institute study found that the risk of a minor crash or crash severe enough to report to police doubled when drivers were talking on a cellphone compared with when they were not visibly distracted. Kidd, D.G; McCartt, A.T. 2015. The relevance of crash type and severity when estimating crash risk using the SHRP2 naturalistic driving data. 4th International Driver Distraction and Inattention Conference. ARRB Group Ltd: Sydney, New South Wales. Similarly, the other study found that talking on a hand-held cellphone doubled crash risk compared with when drivers were not distracted or judged to be driving impaired. Dingus, T.A., Guo, F., Lee, S., et al. 2016. Driver crash risk factors and prevalence evaluation using naturalistic driving data. PNAS, early edition DOI: 10.1073/pnas.1513271113.

    However, another Institute study that took a detailed look at cellphone use during trips made by 105 drivers monitored for one year during 2003-04 found that talking on a cellphone did not significantly increase the risk of a near crash or crash compared with periods where drivers were not talking on the phone as much. Farmer, C.M.; Klauer, S.G.; McClafferty, J.A.; and Guo, F. 2015. Relationship of near-crash/crash risk to time spent on a cellphone while driving. Traffic Injury Prevention 16(8): 792-800.

    Texting or otherwise manipulating a cellphone while driving has consistently been linked to increased risk. The Institute's analysis of data from the 3,000-driver naturalistic study indicated that crash risk was 5 times greater when drivers were manipulating a cellphone compared with when they were not distracted. Kidd, D.G; McCartt, A.T. 2015. The relevance of crash type and severity when estimating crash risk using the SHRP2 naturalistic driving data. 4th International Driver Distraction and Inattention Conference. ARRB Group Ltd: Sydney, New South Wales. Another study based on the same data found that texting alone was associated with a 6-fold increase in crash risk relative to when drivers were not distracted or judged to be driving impaired. Dingus, T.A., Guo, F., Lee, S., et al. 2016. Driver crash risk factors and prevalence evaluation using naturalistic driving data. PNAS, early edition DOI: 10.1073/pnas.1513271113. In the Institute study that took a detailed look at the cellphone use of 105 drivers, reaching for, answering, or dialing a cellphone nearly tripled the risk of a near-crash or crash compared with everything else drivers did while driving; Farmer, C.M.; Klauer, S.G.; McClafferty, J.A.; and Guo, F. 2015. Relationship of near-crash/crash risk to time spent on a cellphone while driving. Traffic Injury Prevention 16(8): 792-800. texting was not prevalent during the study period and was not observed.

  4. How many crashes have been caused by drivers using cellphones or engaging in other distracting behaviors?

    There are no reliable estimates of the number of crashes caused by distracted drivers. Based on national police-reported data on fatal crashes in the United States during 2014, distraction was deemed a contributing factor in the crash for 3,000 of the 44,583 drivers involved in fatal crashes; 398 of these drivers were classified as distracted by cellphone use. National Highway Traffic Safety Administration. 2016. Distracted driving 2014. Report no. DOT HS-812-260. Washington, DC: U.S. Department of Transportation. However, these statistics almost certainly underestimate the role of distraction in fatal crashes. Police crash reports aren't a reliable way to count cellphone-related collisions because drivers often don't volunteer that they were on the phone and there is usually a lack of other evidence to determine drivers' phone use.

    In an in-depth study of a nationally representative sample of police-reported crashes occurring during 2005-07 and involving at least one vehicle towed from the scene, drivers and witnesses were interviewed at the crash scene about driver inattention and other pre-crash behaviors. Singh, S. 2010. Distracted driving and driver, roadway, and environmental factors. Report no. DOT HS 811-380. Washington, DC: National Highway Traffic Safety Administration. Based on these interviews, police reports and other information, a driver was conversing with a passenger in about 16 percent of the crashes. In about 5 percent of the crashes, a driver was focusing on another occupant or object in the vehicle, and in about 3 percent, a driver was using a cellphone (talking, dialing, hanging up or text messaging). In about 2 percent of the crashes, a driver was eating or drinking. The study didn't determine whether these behaviors contributed to the crash. It's likely that the estimates of distraction in this study also are imprecise, as they rely heavily on the accounts of drivers and observers.

  5. How do cellphone use and texting affect driving performance?

    The effect of cellphone use on driving performance has been extensively researched. Based on an Institute review of cellphone and driving research, nearly all experimental studies using driving simulators or instrumented vehicles reported that some measures of driver performance were affected by the cognitive distractions associated with cellphone tasks. McCartt, A.T.; Hellinga, L.A.; and Braitman, K.A. 2006. Cell phones and driving: review of research. Traffic Injury Prevention 7(2):89-106. Statistical analyses that aggregated the results of 33 studies in one analysis and 23 studies in another reported significant delays in drivers' reaction time but little or no effect of cellphone conversations on lane keeping, speed or following distance. Caird, J.K.; Willness, C.R.; Steel, P.; and Scialfa, C. 2008. A meta-analysis of the effects of cell phones on driver performance. Accident Analysis and Prevention 40(4):1282-93. Horrey, W.J. and Wickens, C.D. 2006. Examining the impact of cell phone conversations on driving using meta-analytic techniques. Human Factors 48(1):196-205.

    An analysis aggregating the results of 28 experimental studies using driving simulators or instrumented vehicles reported that typing or reading text messages significantly slowed reaction time, increased lane deviations and increased the length of time drivers looked away from the roadway. Caird, J.K.; Johnston, K.; Willness, C.; Asbridge, M.; and Steel, P. 2014. Synthesis of text messaging and driving performance. Accident Analysis and Prevention 71:311-8.

    Cellphone use also affects how drivers scan and process information from the roadway. Drivers generally take their eyes off the roadway to dial or manipulate a hand-held phone. In contrast, drivers engaged in cellphone conversations and other forms of cognitive distraction tend to concentrate their gaze toward the center of the roadway, Recarte, M.A. and Nunes, L.M. 2000. Effects of verbal and spatial-imagery tasks on eye fixations while driving. J. Exp. Psychol. Appl. 6(1):31-43. Recarte, M.A. and Nunes, L.M. 2003. Mental workload while driving: effects on visual search, discrimination, and decision making. J. Exp. Psychol. Appl. 9(2):119-37. Reimer, B.; Mehler, B.; Wang, Y.; and Coughlin, J. F. 2012. A field study on the impact of variations in short-term memory demands on drivers’ visual attention and driving performance across three age groups. Human Factors 54(3):454-68.
    but their attention still may be diverted from driving and this may make it difficult for drivers to process what they are looking at. Strayer, D.L.; Drews, F.A.; and Johnston, W.A. 2003. Cell phone-induced failures of visual attention during simulated driving. Journal of Experimental Psychology Applied 9(1):23-32. Using brain imaging techniques, researchers found a 37 percent reduction in brain activity associated with driving when subjects performed a task via a headset while steering a simulated vehicle. Just, M.A.; Keller, T.A.; and Cynkar, J. 2008. A decrease in brain activation with driving when listening to someone speak. Brain Research 1205(2008):70-80. Other researchers have found similar suppression of brain activity associated with visual processing and attention when drivers are cognitively distracted. Bowyer, S.M.; Hsieh L.; Moran, J.E.; Young, R.A.; Manoharan, A.; Liao, C.J.; Yu, Y.; Chiang, Y.; and Tepley, N. 2009. Conversation effects on neural mechanisms underlying reaction time to visual vents while viewing a driving scene using MEG. Brain Research  1251(28):151-61. Strayer, D.L.; Martinez, M.; Cooper, J.M.; and Drews, F.A. 2006. Brain waves suppressed by cell phone conversations. Proceedings of the human Factors and Ergonomics Society 50th Annual Meeting, 2364-7. Santa Monica, CA: Human Factors and Ergonomics Society Consequently, cognitive distractions can lead to so-called "inattention blindness" in which drivers fail to comprehend or process information from objects in the roadway even when they are looking at them. Strayer, D.L.; Drews, F.A.; and Johnston, W.A. 2003. Cell phone-induced failures of visual attention during simulated driving. Journal of Experimental Psychology Applied 9(1):23-32.  

  6. How common are laws limiting drivers' use of cellphones?

    Bans on hand-held phone conversations while driving are widespread in other countries and are becoming more common in the U.S. In 2001, New York became the first state to ban hand-held phone conversations by all drivers. Now, 14 states and the District of Columbia have similar laws.

    In 2002, New Jersey became the first state to limit young drivers’ use of any kind of cellphone. Now 37 states and the District of Columbia have similar restrictions. The District of Columbia in 2004 and Connecticut in 2005 prohibited texting while driving as part of a law broadly addressing driver distraction.  In January 2008, Washington became the first state to prohibit texting specifically by all drivers. Now texting is banned for all drivers in 46 states and the District of Columbia, and an additional two states (Missouri and Texas) prohibit texting only for novice drivers.

    Cellphone laws in the U.S.

  7. Do drivers comply with bans on hand-held phone use and texting?

    Institute research has documented that all-driver bans on hand-held phone conversations can have large and lasting effects on phone use. Based on observations of drivers conducted up to seven years after bans were implemented in New York, the District of Columbia and Connecticut, the rates of driver hand-held cellphone conversations were an estimated 24-76 percent lower than would have been expected without a ban. McCartt, A.T.; Hellinga, L.A.; Strouse, L.M.; and Farmer, C.M. 2010. Long-term effects of handheld cell phone laws on driver handheld cell phone use. Traffic Injury Prevention 11(2):133-41. In a 2009 telephone survey, 56 percent of drivers in states with bans reported they use phones when driving, compared with 69 percent in states without such laws. Braitman, K.A. and McCartt, A.T. 2010. National reported patterns of driver cellphone use. Traffic Injury Prevention 11(6):543-8. The proportion of drivers who talked on phones and always talked hands-free was 22 percent in states with all-driver bans on hand-held phones and 13 percent in states without all-driver bans.

    Phone bans seem to have less effect on younger drivers. Since Dec. 1, 2006, North Carolina has banned the use of any telecommunications device by drivers younger than 18. Eleven percent of teenagers leaving high schools in the afternoon were using phones prior to the ban, and this did not change significantly when measured five months after the restriction took effect or two years later. Foss, R.D.; Goodwin, A.H.; McCartt, A.T.; and Hellinga, L.A. 2009. Short-term effects of a teenager driver cell phone restriction. Accident Analysis and Prevention 41(3):419-24. Goodwin, A. H.; O’Brien, N.; and Foss, R.D. 2012. Effect of North Carolina’s restriction on teenage driver cell phone use two years after implementation. Accident Analysis and Prevention 48:363-67.

    There is scant information on drivers' compliance with texting bans. The Institute's 2009 survey of drivers found that among 18-24 year-olds, 45 percent reported texting while driving in states that bar the practice, just shy of the 48 percent of drivers who reported texting in states without bans. Braitman, K.A. and McCartt, A.T. 2010. National reported patterns of driver cellphone use. Traffic Injury Prevention 11(6):543-8. Among drivers ages 25-29, 40 percent reported texting in states with bans, compared with 55 percent in states without bans.

    The National Highway Traffic Safety Administration has conducted high-visibility enforcement campaigns in Hartford, Conn., Syracuse, N.Y., the Sacramento Valley Region in California, and in the state of Delaware as a way to increase compliance with cellphone and texting bans. After programs of publicized, high-intensity enforcement of hand-held cellphone and texting bans were implemented, the number of drivers observed holding a phone to their ear declined by 57 percent in Hartford, 32 percent in Syracuse, 34 percent in the Sacramento Valley region and 33 percent in Delaware. Cosgrove, L.; Chaudhary, N.; and Reagan, I. 2011. Four high-visibility enforcement demonstration waves in Connecticut and New York reduce hand-held phone use. Report No. DOT HS 811-845. Washington, DC: U.S. Department of Transportation. Schick, A.; Vegega, M.; and Chaudhary, N. 2014. Distracted driving high-visibility enforcement demonstrations in California and Delaware. Report no. DOT HS-811-993. Washington, DC: National Highway Traffic Safety Administration. Significant declines also were observed in 3 of the 4 groups of comparison communities where high-visibility enforcement campaigns were not conducted. Observed manipulation of hand-held phones (e.g., dialing, texting) decreased significantly in Syracuse, N.Y., and Hartford, Conn., following the enforcement initiative and did not decrease in the comparison communities.

  8. Do bans on hand-held phone use and texting reduce crashes?

    It is not clear whether banning hand-held phone use or texting reduces crashes. A 2009 analysis by the Highway Loss Data Institute (HLDI) found that hand-held bans had no effect on insurance collision claim rates. Trempel, R. E.; Kyrychenko, S. Y.; and Moore, M. J. 2011. Does banning hand-held cell phone use while driving reduce collisions? Chance 24(3):6-11. Researchers compared rates of claims for crash damage in three states and the District of Columbia before and after hand-held phone use bans went into effect and found no significant change in claim rates for two jurisdictions relative to comparison states and small, but significant, increases in claim rates in the other two.

    A 2010 HLDI study examined rates of insurance collision claims before and after driver texting bans were enacted in four states. Highway Loss Data Institute. 2010. Texting laws and collision claim frequencies. HLDI Bulletin 27(11). Arlington, VA. There was no significant change in one state relative to comparison states and significant increases of 7-9 percent in three states. Increases in claim rates also were found for drivers 25 and younger in these three states.

    The Institute reviewed 11 studies of the effects of all-driver hand-held phone bans and texting bans on crashes, including the two HLDI studies. McCartt, A.T.; Kidd, D.G.; and Teoh, E.R. 2014. Driver cellphone and texting bans in the United States: evidence of the effectiveness. Annals of Advances in Automotive Medicine 58:99-114. The results were mixed, so it is not clear if laws limiting drivers' cellphone use are having beneficial effects on crashes. Bans may not have a beneficial effect on crashes even with strong enforcement. Four waves of enforcement campaigns aimed at reducing hand-held cellphone use were conducted in Hartford, Conn., and Syracuse, N.Y, during 2010-11. The campaigns reduced observed rates of cellphone conversation and manipulating. However, an analysis comparing insurance collision claims in counties with the campaigns to comparison counties without them did not find a corresponding reduction in crashes reported to insurers. Highway Loss Data Institute. 2013. Evaluation of U.S. DOT special enforcement campaigns for hand-held cellphone and texting bans. HLDI Bulletin 30(35). Arlington, VA.

  9. Can technology be used to reduce crash risks related to distracted driving?

    Crash avoidance technology may be the most promising avenue for reducing crash risks related to distractions of any type. Field studies of several prototype collision warning systems suggest these systems may not reduce the prevalence of distracted driving; Jermakian, J.S.; Bao, S.; Buonarosa M.L.; Sayer J. 2015. Effects of an integrated collision warning system on teenage driver behavior. Arlington, VA: Insurance Institute for Highway Safety. Sayer, J.R.; Bogard, S.E.; Buonarosa, M.L.; LeBlanc, D.J.; Funkhouser, D.S.; Bao, S.; Blankespoor, A.D.; Winkler, C.B. 2011. Integrated vehicle-based safety systems light-vehicle field operational test key findings report (DOT HS 811 416). Washington, DC: U.S. Department of Transportation. however, these technologies can help prevent or mitigate crashes. Warnings can redirect a distracted, inattentive or sleepy driver's attention back to the roadway if it detects the potential for a collision. Some systems attempt to avoid the collision altogether if a driver does not respond fast enough or does not respond at all.

    Automakers are integrating "infotainment" systems into vehicles to let drivers and other occupants plug in or wirelessly connect portable electronic devices such as cellphones to vehicle entertainment and communication systems. Many newer infotainment systems and portable devices can be controlled using voice commands. Several experimental studies have shown that drivers take shorter glances away from the roadway and keep their eyes on the road for a greater proportion of the time when interacting with a portable device using voice commands than when using their hands. Ranney, T. A.; Harbluk, J. L.; and Noy, Y. I. 2005. Effects of voice technology on test track driving performance: implications for driver distraction. Human Factors 47(2):439-54. Owens, J. M.; McLaughlin, S.B.; and Sudweeks, J. 2010. On-road comparison of driving performance measures when using handheld and voice-control interfaces for mobile phones and portable music players. Paper No. 2010-01-1036. SAE 2010 World Congress & Exhibition. SAE International: Warrendale, PA. Owens, J. M.; McLaughlin, S. B.; and Sudweeks, J. 2011. Driver performance while text messaging using handheld and in-vehicle systems. Accident Analysis & Prevention 43(3): 939-47. Mehler, B.; Kidd, D.; Reimer, B.; Reagan, I.; Dobres, J.; and McCartt, A. 2015. Multi-modal assessment of on-road demand of voice and manual phone calling and voice navigation entry across two embedded vehicle systems. Ergonomics, in press.
    Reimer, B.; Mehler, B.; Reagan, I.; Kidd, D.; and Dobres, J. 2015. Multi-modal demands of a smartphone used to place calls and enter addresses during highway driving relative to two embedded systems. Ergonomics, in press.

    However, voice systems are not all designed the same, Reagan, I.J. and Kidd, D.G. 2013. Using hierarchical task analysis to compare four vehicle manufacturers' infotainment systems. Proceedings of the Human Factors and Ergonomics Society Annual Meeting, 1495-2599. Santa Monica, CA: Human Factors and Ergonomics Society. and the benefits can vary. An Institute study found that drivers were able to place calls and enter addresses into a navigation system during highway driving more quickly and keep their eyes on the roadway longer when using a system in which a single detailed voice command was used to complete the tasks compared with a system in which multiple voice commands were used to navigate different menus. Mehler, B.; Kidd, D.; Reimer, B.; Reagan, I.; Dobres, J.; and McCartt, A. 2015. Multi-modal assessment of on-road demand of voice and manual phone calling and voice navigation entry across two embedded vehicle systems. Ergonomics, in press.
    On the flip side, drivers experience many more errors when entering an address using a single voice command than when entering it using voice commands. The effects of voice recognition technology on crash risk are unknown. NHTSA has issued voluntary guidelines for integrated infotainment systems in an effort to minimize the visual and manual distraction potential of these systems. Office of the Federal Register. 2012. National Highway Traffic Safety Administration. Docket no. NHTSA-2010-0053 - Visual manual NHTSA Driver Distraction Guidelines for in-vehicle electronic devices. Federal Register, vol. 77, no. 80, pp. 24764-66. Washington, DC: National Archives and Records Administration.

    Phone applications that restrict or limit access to electronic devices also have been developed. These apps generally work when vehicles are in motion and can silence the phone, redirect incoming calls to voicemail or respond to text messages with a preprogrammed message. A study examining phone use during work-related driving found that when phone use was restricted by a blocking application, employees answered fewer calls with their employer-provided phones while the vehicle was moving and made more calls when the vehicle was stopped. Funkhouser, D. and Sayer, J.R. 2014. Cell phone filter/blocking technology field test. Report no. DOT HS-811-863. Washington, DC: National Highway Traffic Safety Administration. Another study examining smartphone use among 182 novice teens over one year found that teens who had an app on their smartphone that restricted cellphone use and blocked incoming calls and messages made significantly fewer calls and texts per mile driven compared with teens who did not have the app. Creaser, J.I.; Edwards, C.J.; Morris, N.L.; Donath, M. 2015. Are cellular phone blocking applications effective for novice teen drivers? Journal of Safety Research 75: e29-78. At this point, it is unclear to what extent these apps are used and to what extent they affect crash risk.