Understanding the Problem

The public perceives driver distraction to be a serious traffic safety issue. In 2020 the AAAFTS (2021) surveyed more than 2,800 U.S. motorists and found that 96% of respondents said using a cell phone to text or email while driving was extremely or very dangerous. Similarly, in 2015 NHTSA conducted 6,001 telephone interviews and asked respondents how safe they would feel in a variety of situations in which they are passengers in vehicles operated by drivers who are engaged in other activities. Almost two-thirds (65%) said they would feel “somewhat” or “very” unsafe if the driver talked on a handheld cell phone, and almost all (95%) would feel unsafe if the driver sent text messages or emails (Schroeder et al., 2018).

Although people are concerned about distracted driving, they frequently admit to engaging in such behaviors behind the wheel. In the AAAFTS (2021) survey, 37% of respondents admitted to talking on the phone while driving during the past 30 days. Thirty-four percent admitted to reading a text or email while driving, while 23% had manually typed or sent an email or text message. The NHTSA survey also asked about a variety of behaviors related to distracted driving (Schroeder et al., 2018). Among the behaviors that drivers reported doing at least sometimes:

• 82% talked to other passengers;
• 68% adjusted the car radio;
• 48% ate or drank;
• 42% interacted with children in the back seat;
• 38% made or accepted phone calls;
• 36% used a navigational system;
• 12% read email or text messages;
• 9% sent text messages or email;
• 5% took pictures with phones.

People perceive the use of hands-free devices as less risky than handheld devices. Nearly half (47%) of the respondents in the NHTSA survey reported feeling safe if the driver was using a hands-free cell phone to make or answer calls, compared to just 35% for handheld phones (Schroeder et al., 2018).

Each year, NHTSA conducts a nationwide observational survey of driver electronic device use—the NOPUS. Observations are conducted by trained data collectors from 7 a.m. to 6 p.m. During 2021 an estimated 7.6% of drivers were using some type of phone (handheld or hands-free) at any given moment during the daytime (NCSA, 2022). Among different subgroups, observed cell phone use while driving was higher among females, younger drivers, drivers in urban areas, and drivers who were not carrying passengers.

More than one factor can affect drivers’ decisions to engage in distracted driving. Most often, the perceived benefits outweigh the perceived risks (Lissy et al., 2000). A study of 249 university undergraduate students reported that the perceived benefits of cell phone conversations while driving include less boredom and the feeling of “getting more done” (Sanbonmatsu et al., 2016). Students who reported using their cell phones while driving were also more likely to perceive higher ability to drive when distracted for themselves and others. Unsurprisingly, these students were also less likely to support legislation to restrict cell phone use while driving. The presence of legislation regulating cell phone use does not necessarily prevent drivers from engaging in such behaviors. An analysis of reported cell phone use among U.S. adolescent drivers (16-18 years) was conducted using the 2011 to 2014 Traffic Safety Culture surveys. The study found that legislation banning handheld phone use may lower the incidence of reported phone conversations in this population; however, texting bans were not associated with similar decreases in reported texting behaviors while driving (Rudisill et al., 2018).

The role of distraction in crashes is difficult to ascertain. Pre-crash distractions often leave no evidence for law enforcement officers or crash investigators to observe, and drivers are often reluctant to admit to having been distracted prior to a crash. Distraction-affected crashes is a measure that focuses on distractions that are most likely to influence crash involvement, such as dialing a cell phone or texting, and distraction by an outside person/event (NHTSA, 2012). According to NHTSA’s National Center for Statistics and Analysis, there were 3,522 fatalities in distraction-affected crashes in 2021, an increase of 368 fatalities in comparison to 2020 (NCSA, 2023). Eight percent of all fatal crashes in 2021 were distraction-affected crashes.

Additionally, police crash reports vary across jurisdictions in reporting distracted driving. Some jurisdictions identify distraction as a distinct field in the reports, whereas others identify distraction in the crash narrative. This inconsistency in reporting leads to wide variation in the number of distracted driving crashes between States.

The risks posed by specific distracted driving behaviors are beginning to be understood thanks to naturalistic driving studies that use onboard sensors and cameras to capture data right before crashes as well as during normal driving situations. The Second Strategic Highway Research Program Naturalistic Driving Study (SHRP2 NDS) included 3,500 participants, 35 million miles of continuous driving data, and 905 injury and PDO crashes. Researchers have used SHRP2 data to examine the crash risk associated with various observable distractions compared to regular driving (Dingus et al., 2016). The table below shows the change in crash risk when drivers are engaged in potentially distracting behaviors. For example, using a handheld cell phone increases the risk of a crash 3.6 times compared to not using a phone. The table also shows baseline percentage of time drivers engaged in a distracting task while driving. The distractions that increased risk the most were dialing a handheld phone, texting, reading/writing, reaching for an object, and looking at an object outside the vehicle. Each of these involves several sources of distraction. For example, dialing or texting on a handheld cell phone takes a driver’s hands, eyes, and attention away from the task of driving. Talking on a handheld phone did not increase crash risk to the same extent, but drivers engaged in this behavior more often than other types of distractions.

Estimated Change in Crash Risk When Engaging in Potentially Distracting Behaviors, SHRP2 Study of U.S. Drivers

Type of Distraction	Change in Risk (Odds Ratio, 95% CI)	Baseline Prevalence
Total handheld cell phone use	3.6 (2.9 – 4.5)	6.4%
Dialing	12.2 (5.6 – 26.4)	0.1%
Texting	6.1 (4.5 – 8.2)	1.9%
Reaching	4.8 (2.7 – 8.4)	0.6%
Browsing	2.7 (1.5 – 5.1)	0.7%
Talking	2.2 (1.6 – 3.1)	3.2%
Total in-vehicle device use	2.5 (1.8 - 3.4)	3.5%
Adjusting the climate controls	2.3 (1.1 – 5.0)	0.6%
Adjusting the radio	1.9 (1.2 – 3.0)	2.2%
Adjusting other device (e.g., touchscreen)	4.6 (2.9 – 7.4)	0.8%
Reading/writing (including tablet)	9.9 (3.6 – 26.9)	0.1%
Reaching for object (other than cell phone)	9.1 (6.5 – 12.6)	1.1%
Looking at outside object	7.1 (4.8 – 10.4)	0.9%
Eating	1.8 (1.1 – 2.9)	1.9%

Source: Dingus et al. (2016).

A recent study focused on the relationship between drivers’ handheld cell phone use and subsequent crash involvement. Owens et al. (2018) performed a case-crossover analysis using the SHRP2 NDS data. A total of 566 crashes of varying severity were matched to 1,749 instances of normal driving on variables including the subject driver, weather, time of day, and speed. The use of handheld cell phones in general, and specifically performing tasks with visual and manual elements (such as texting) were significantly associated with increased crash involvement (excluding crashes where the driver was struck from behind). Of the visual-manual tasks, texting was significantly associated with increased crash involvement. The table below presents these changes in crash involvement when using a handheld cell phone relative to driving without performing secondary tasks.

Estimated Change in Crash Risk When Using a Handheld Cell Phone Relative to Driving Without Performing Secondary Tasks

Type of Distraction	Change in Risk (Odds Ratio, 95% CI)
Any cell phone use	1.80 (1.06 - 3.07)
Overall visual-manual tasks	2.19 (1.19 – 4.02)
Texting	2.54 (1.18 – 5.50)

Source: Owens et al. (2018).

The study also found that increases in crash involvement associated with visual-manual tasks were greater for crashes in free-flow traffic. Rear-end crashes and run-off road crashes were more prevalent in the crash data than other types of crashes; drivers’ visual-manual cell phone interactions were associated with increased instances of both these crash types. Run-off road crashes were also significantly associated with any cell phone use (Owens et al., 2018). There are differences between the Owens et al. study and the Dingus et al. study as to what was controlled for, but the differences in odds ratios indicate that more research is needed.

Another naturalistic study was conducted from 2007 to 2015 with approximately 15,000 teen drivers (16 to 19 years old). Videos of a total of 2,229 moderate to severe crashes were analyzed (Carney et al., 2018). About 59% of these crashes involved teen drivers who were distracted in the 6 seconds prior to a crash. The most common distractions included attending to passengers (15%), using a cell phone for any purpose (12%), or attending/reaching inside the vehicle (11%). Similarly, Klauer et al. (2014) used a naturalistic study to examine distracted behaviors and their effects on the risk of being involved in a crash or near crash among 42 newly licensed (novice) drivers. Some of the findings are shown in the table below. Novices were eight times more likely to be involved in a crash or near crash when dialing a cell phone and seven times more likely to be involved in a crash or near crash when reaching for a cell phone. These findings are consistent with the SHRP2 NDS study described above and demonstrate that the risks posed by various types of distraction are problematic for young drivers just as they are for the general driving population.

Estimated Change in Crash Risk When Engaging in Potentially Distracting Behaviors, Newly Licensed (Novice) Drivers

Type of Distraction	Change in Risk (Odds Ratio, 95% CI)
Using a cell phone
Dialing	8.3 (2.8 – 24.4)
Reaching for phone	7.1 (2.6 – 18.9)
Texting	3.9 (1.6 – 9.3)
Reaching for object (other than cell phone)	8.0 (3.7 – 17.5)
Looking at outside object	3.9 (1.7 – 8.8)
Eating	3.0 (1.3 – 6.9)

Source: Klauer et al. (2014).

None of the distractions listed in the tables above are easily addressed by current behavioral countermeasures, to limit distracted driving. One reason is it is difficult to convince or require drivers to avoid distractions while driving. Many drivers consider some distractions, such as eating or drinking, listening to the radio, or talking on a cell phone, to be important activities and they are unlikely to give them up. Moreover, studies indicate that drivers themselves are poor judges of the performance decrements that result from distracting activities (Horrey et al., 2008). The 2015 NHTSA survey found that a large portion of drivers do not believe that their driving performance is affected by cell phone use, and that over half of drivers who talk on the phone while driving believe that their driving is the same while using a cell phone (Schroeder et al., 2018).

Few studies have examined if the standard behavioral countermeasures of laws, enforcement, and sanctions (which are used successfully for impaired driving, seat belt use, and speeding) are effective for distracted drivers. The results of three NHTSA demonstration projects, focused on HVE that includes paid and earned media, suggest that these elements show promise in reducing the use of handheld phones and texting (Cosgrove et al., 2011). With respect to young drivers, some States address distracted driving through graduated driver licensing provisions such as limiting teenage passengers, or by restricting cell phone use.

Job-related distracted driving may be addressed through employer policies and programs. Employer-based resources are available from the Network of Employers for Traffic Safety through trafficsafety.org. The National Safety Council (NSC) provides resources to employers, including an online distracted driving course and the National Distracted Driving Committee has sample employer policies.

Although behavioral countermeasures are limited, several engineering strategies have the potential to address distracted driving. Rumble strips, both on the shoulder and the centerline, have demonstrated their effectiveness in preventing crashes associated with inattention (Persaud et al., 2016). Engineering countermeasures are not discussed in this guide because they generally do not fall under the jurisdiction of SHSOs.

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