Driver Cellphone and Texting Bans in the United States: Evidence of Effectiveness.(NCBI).

Abstract

Almost all U.S. states have laws limiting drivers’ cellphone use. The evidence suggests that all-driver bans on hand-held phone conversations have resulted in long-term reductions in hand-held phone use, and drivers in ban states reported higher rates of hands-free phone use and lower overall phone use compared with drivers in non-ban states. Bans on all phone use by teenage drivers have not been shown to reduce their phone use. The effects of texting bans on the rates of drivers’ texting are unknown. With regard to the effects of bans on crashes, 11 peer-reviewed papers or technical reports of all-driver hand-held phone bans and texting bans were reviewed. Some were single-state studies examining crash measures before and after a state ban; other national or multi-state studies compared crashes in states with and without bans over time. The results varied widely. The lack of appropriate controls and other challenges in conducting strong evaluations limited the findings of some studies. Thus, despite the proliferation of laws limiting drivers’ cellphone use, it is unclear whether they are having the desired effects on safety. Priorities for future research are suggested.

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INTRODUCTION

Strong laws with publicized strong enforcement are a proven countermeasure for changing driver behavior. This approach, for example, has led to increases in seat belt use [Dinh-Zarr, Sleet, Shults, et al., 2001; Tison, Williams, 2010], decreases in alcohol-impaired driving [Shults, Elder, Sleet, et al., 2001; Wells, Preusser, Williams, 1992], and ultimately reductions in crash deaths [Farmer, Williams, 2006; Dinh-Zarr et al., 2001;Shults et al., 2001]. As cell-phones began to proliferate in the late 1990s, a number of experimental studies found decrements in simulated or instrumented driving performance associated with phone use [McCartt, Hellinga, Braitman, 2006], and a well-publicized epidemiological study found a fourfold increase in the risk of a property damage-only crash associated with a driver’s phone conversation [Redelmeier, Tibshirani, 1997]. Bolstered by this research, concerns about the risks of drivers’ cellphone use led to the passage of laws limiting use. These laws are widespread in other countries and are increasingly common in the United States. This paper summarizes the research on the effectiveness of these laws in the United States.

On November 1, 2001, New York became the first state to implement a law prohibiting all drivers from talking on a hand-held cellphone while driving. Currently a total of 12 states and the District of Columbia have such laws. All of the laws allow emergency calls, most allow hand-held dialing, and some allow talking when stopped in traffic, at controlled intersections, or on the side of the road. The language in early hand-held cellphone laws in Connecticut (effective October 1, 2005) and the District of Columbia (effective July 1, 2004) covered text messaging, but Washington enacted the first law specifically banning all drivers from texting, effective January 1, 2008. Many states rapidly followed suit, and currently 41 states and the District of Columbia prohibit texting by all drivers. Beginning with New Jersey on January 8, 2002, 37 states and the District of Columbia have implemented laws targeting teenage drivers. These laws generally prohibit any use of an electronic device/telecommunications device/ cellphone, whether hands-free or hand-held; the laws may be based on age (e.g., younger than 18) or license stage (e.g., learner’s permit or intermediate license). Only three states — Arizona, Montana, and South Carolina — have no laws limiting drivers’ cellphone use. Thus, currently there is a patchwork of laws limiting drivers’ cellphone use across the United States.Appendix A summarizes the history of the all-driver hand-held cellphone laws, all-driver texting laws, and teenage driver cellphone laws, including effective dates and key provisions.

Conducting rigorous evaluations of highway safety laws can be challenging. Ideally, information can be obtained to measure meaningful changes in the targeted behavior following implementation of the law and corresponding changes in crashes, injuries, or fatalities. For the link between a law and crash outcomes to be convincing, there should be strong evidence of an elevated crash or injury risk associated with the targeted behavior, and the crash measure should be consistent with this evidence.

However, the crash risk associated with using a cell-phone while driving is not well understood. Part of the challenge is that the contribution of phone use or other distractions to crashes is not fully or consistently recorded in databases of police-reported crashes [e.g., National Safety Council, 2013]. The chief problem is that drivers are unlikely to volunteer that they were using phones, especially if it is illegal, and there usually is no other evidence of phone use at the crash scene. In addition, reporting practices likely have changed as the issue of distraction has grown in prominence and as states have enacted laws limiting cellphone use and added codes for cellphone use to crash report forms.

Figure 1 plots the annual percentage of crash deaths coded as involving driver distraction during 1999–2012 in each of several states and nationally. These data come from the Fatality Analysis Reporting System (FARS), a national census of crashes that occur on public roads and result in at least one death within 30 days. There are large, unexplained differences among the states and year-to-year anomalies within some states. For example, during 1997–2007, the proportion of crash deaths coded as involving distraction was 45–63% in New Mexico and 6–26% in California. Even after coding changes were implemented in 2010 to address some of the reporting problems, anomalies and inconsistencies have persisted. Thus, data on cellphone-related crashes in crash databases do not provide a solid basis for establishing the prevalence of cellphone-related crashes, supporting epidemiological research on the risks of cellphone use, or evaluating the effectiveness of cellphone bans.

Figure 1.

Percentage of Deaths in Crashes Coded as Involving Driver Distraction in the Fatality Analysis Reporting System, 1999–2012

Another challenge is that the findings from the few studies that have estimated crash risk associated with cellphone use are mixed. Two studies obtained cell-phone billing records to verify phone use of drivers involved in property damage-only crashes [Redelmeier, Tibshirani, 1997] and in crashes serious enough to injure the drivers [McEvoy, Stevenson, McCartt, et al., 2005]. Using a case-crossover design, both studies found a fourfold increase in crash risk associated with phone conversations; the increased risk was similar for hands-free and hand-held phone use. Although the case-crossover designs accounted for possible driver differences, they assume the reasons for phone use are independent of crash risk, which may not be the case. Drivers with higher crash risk, who were more likely to get into the studies, may be affected by cellphone use differently than less risky drivers. Plus, the subjects may have had imperfect recall of whether or not they drove during control periods.

Patrick Abboud

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