Cell phone use while driving laws and motor vehicle driver fatalities: differences in population subgroups and location

Effectiveness of road safety interventions: An evidence and gap map

Background

Road Traffic injuries (RTI) are among the top ten leading causes of death in the world resulting in 1.35 million deaths every year, about 93% of which occur in low- and middle-income countries (LMICs). Despite several global resolutions to reduce traffic injuries, they have continued to grow in many countries. Many high-income countries have successfully reduced RTI by using a public health approach and implementing evidence-based interventions. As many LMICs develop their highway infrastructure, adopting a similar scientific approach towards road safety is crucial. The evidence also needs to be evaluated to assess external validity because measures that have worked in high-income countries may not translate equally well to other contexts. An evidence gap map for RTI is the first step towards understanding what evidence is available, from where, and the key gaps in knowledge.

Objectives

The objective of this evidence gap map (EGM) is to identify existing evidence from all effectiveness studies and systematic reviews related to road safety interventions. In addition, the EGM identifies gaps in evidence where new primary studies and systematic reviews could add value. This will help direct future research and discussions based on systematic evidence towards the approaches and interventions which are most effective in the road safety sector. This could enable the generation of evidence for informing policy at global, regional or national levels.

Search Methods

The EGM includes systematic reviews and impact evaluations assessing the effect of interventions for RTI reported in academic databases, organization websites, and grey literature sources. The studies were searched up to December 2019.

Selection Criteria

The interventions were divided into five broad categories: (a) human factors (e.g., enforcement or road user education), (b) road design, infrastructure and traffic control, (c) legal and institutional framework, (d) post-crash pre-hospital care, and (e) vehicle factors (except car design for occupant protection) and protective devices. Included studies reported two primary outcomes: fatal crashes and non-fatal injury crashes; and four intermediate outcomes: change in use of seat belts, change in use of helmets, change in speed, and change in alcohol/drug use. Studies were excluded if they did not report injury or fatality as one of the outcomes.

Data Collection and Analysis

The EGM is presented in the form of a matrix with two primary dimensions: interventions (rows) and outcomes (columns). Additional dimensions are country income groups, region, quality level for systematic reviews, type of study design used (e.g., case-control), type of road user studied (e.g., pedestrian, cyclists), age groups, and road type. The EGM is available online where the matrix of interventions and outcomes can be filtered by one or more dimensions. The webpage includes a bibliography of the selected studies and titles and abstracts available for preview. Quality appraisal for systematic reviews was conducted using a critical appraisal tool for systematic reviews, AMSTAR 2.

Main Results

The EGM identified 1859 studies of which 322 were systematic reviews, 7 were protocol studies and 1530 were impact evaluations. Some studies included more than one intervention, outcome, study method, or study region. The studies were distributed among intervention categories as: human factors (n = 771), road design, infrastructure and traffic control (n = 661), legal and institutional framework (n = 424), post-crash pre-hospital care (n = 118) and vehicle factors and protective devices (n = 111). Fatal crashes as outcomes were reported in 1414 records and non-fatal injury crashes in 1252 records. Among the four intermediate outcomes, speed was most commonly reported (n = 298) followed by alcohol (n = 206), use of seatbelts (n = 167), and use of helmets (n = 66). Ninety-six percent of the studies were reported from high-income countries (HIC), 4.5% from upper-middle-income countries, and only 1.4% from lower-middle and low-income countries. There were 25 systematic reviews of high quality, 4 of moderate quality, and 293 of low quality.

Authors' Conclusions

The EGM shows that the distribution of available road safety evidence is skewed across the world. A vast majority of the literature is from HICs. In contrast, only a small fraction of the literature reports on the many LMICs that are fast expanding their road infrastructure, experiencing rapid changes in traffic patterns, and witnessing growth in road injuries. This bias in literature explains why many interventions that are of high importance in the context of LMICs remain poorly studied. Besides, many interventions that have been tested only in HICs may not work equally effectively in LMICs. Another important finding was that a large majority of systematic reviews are of low quality. The scarcity of evidence on many important interventions and lack of good quality evidence-synthesis have significant implications for future road safety research and practice in LMICs. The EGM presented here will help identify priority areas for researchers, while directing practitioners and policy makers towards proven interventions.

A randomized controlled pilot trial of brief online mindfulness training in young drivers

OBJECTIVE

Driver distraction contributes to fatal and injury crashes in young drivers. Mind wandering (MW) is a covert form of distraction involving task-unrelated thoughts. Brief online mindfulness training (MT) may reduce unsafe driving by enhancing recognition (meta-awareness) of MW and reducing its occurrence. This pilot trial tested these proposed mechanisms of MT and explored its specificity of action, effects on driving behaviour in simulation, as well as intervention adherence and acceptability in young drivers.

METHODS

A pre-post (T1, T2), randomized, active placebo-controlled, double-blinded design was used. Twenty-six drivers, aged 21-25, received either brief online MT (experimental) or progressive muscle relaxation (PMR, control) over 4-6 days. A custom website blindly conducted randomization, delivered interventions, administered questionnaires, and tracked adherence. At T1 and T2, a simulator measured driving behaviour while participants indicated MW whenever they recognized it, to assess meta-awareness, and when prompted by a thought-probe, to assess overall MW.

RESULTS

MT reduced MW while driving in simulation. The MT group reported higher state mindfulness following sessions. Motivation did not account for MW or mindfulness results. MT and meta-awareness were associated with more focus-related steering behaviour. Intervention groups did not significantly differ in adherence or attrition. No severe adverse effects were reported, but MT participants reported more difficulty following intervention instructions.

CONCLUSION

Results support a plausible mechanism of MT for reducing MW-related crash risk (i.e., reduction of MW) in young drivers. This preliminary evidence, alongside promising online adherence and acceptability results, warrants definitive efficacy and effectiveness trials of online MT.

The association between strengthened cellphone laws and police-reported rear-end crash rates

INTRODUCTION

Prior evaluations of the connection between cellphone bans and crashes show unclear results. California, Oregon, and Washington enacted legislation (effective in 2017) to update earlier bans specific to handheld conversation and texting. This study evaluated the relationship between the laws and rear-end rates, a crash type sensitive to visual-manual cellphone use, in California, Oregon, and Washington.

METHOD

Negative binomial regression compared the change in monthly per capita rear-end crash rates in California, Oregon, and Washington before and after the law changes relative to two control states, Colorado and Idaho, during 2015-2019. Analyses examined (a) rear-end crashes with injuries in all three study states, including minor to fatal injuries; and (b) rear-end crashes of all severities in California and Washington, including property-damage-only crashes and crashes with injuries; Oregon was excluded from this analysis because of a 2018 change to its reporting criteria for property-damage-only crashes.

RESULTS

Washington's strengthened law was associated with a significant 7.6% reduction in the rate of monthly rear-end crashes of all severities relative to the controls. Law changes in Oregon and Washington were associated with significant reductions of 8.8% and 10.9%, respectively, in the rates of monthly rear-end crashes with injury relative to the controls. California did not experience changes in rear-end crash rates of all severities or with injuries associated with the strengthened law.

CONCLUSION

The results of this study are mixed, with law changes associated with significant reductions in rear-end crash rates in two of the three study states. Differences in the wording of the laws, levels of enforcement, and sanction severity may help explain the divergent results.

PRACTICAL APPLICATION

Crash reductions in Oregon and Washington suggest that enacting legislation that comprehensively bans practically all visual-manual cellphone activity may have made the laws easier to enforce and clarified to drivers that handheld cellphone use is unacceptable in these states.

Short-term impacts of all-driver handheld cellphone bans on high-schoolers' texting while driving: quasi-experimental analyses of Illinois and Georgia

Teen drivers are more likely than their older counterparts to engage in distracted driving. Many states prohibit cellphone use for teen drivers, but only prohibit texting for all drivers. Evidence that these laws have been effective is mixed. We hypothesize that recent policy changes in Georgia and Illinois from teen cellphone bans with all-driver texting bans to all-driver handheld phone bans yielded short-term reductions in teen texting while driving. We analyzed Youth Risk Behavior Surveys in Georgia, Illinois, and control states North Carolina and Michigan. We estimated the reduction in texting while driving associated with policy changes via difference-in-differences models. In Illinois, 45.4 % of high school drivers texted while driving in 2013. After a 2014 policy change to an all-driver handheld ban, the percentage decreased in 2015 to 41.8 %, and decreased further in 2017 to 37.7 %. The adjusted DID estimate comparing Illinois to Michigan from 2013 to 2017 was -8.3 % (95 % CI: -15.5 % 1.1 %; p-value = 0.025). In Georgia, the percentage decreased from 37.5 % before the law to 30.8 % after, and the adjusted DID estimate comparing Georgia to North Carolina was -10.8 % (95 % CI: -19.0 %, -2.5 %; p-value = 0.011) than in North Carolina. Results support all-driver handheld phone bans to improve traffic safety for high school drivers.

The impact of Illinois' comprehensive handheld phone ban on talking on handheld and handsfree cellphones while driving

INTRODUCTION

Distracted driving has been linked to multiple driving decrements and is responsible for thousands of motor-vehicle fatalities annually. Most U.S. states have enacted restrictions on cellphone use while driving, the strictest of which prohibit any manual operation of a cellphone while driving. Illinois enacted such a law in 2014. To better understand how this law affected cellphone behaviors while driving, associations between Illinois' handheld phone ban and self-reported talking on handheld, handsfree, and any cellphone (handheld or handsfree) while driving were estimated.

METHODS

Data from annual administrations of the Traffic Safety Culture Index from 2012-2017 in Illinois and a set of control states were leveraged. The data were cast into a difference-in-differences (DID) modeling framework, which compared Illinois to control states in terms of pre- to post-intervention changes in the proportion of drivers who self-reported the three outcomes. Separate models for each outcome were fit, and additional models were fit to the subset of drivers who talk on cellphones while driving.

RESULTS

In Illinois, the pre- to post-intervention decrease in the drivers' probability of self-reporting talking on a handheld phone was significantly more extreme than that of drivers in control states (DID estimate -0.22; 95% CI -0.31, -0.13). Among drivers who talk on cellphones while driving, those in Illinois exhibited a more extreme increase in the probability of talking on a handsfree phone while driving than those control states (DID estimate 0.13; 95% CI 0.03, 0.23).

CONCLUSIONS

These results suggest that Illinois' handheld phone ban reduced talking on handheld phones while driving among study participants. They also corroborate the hypothesis that the ban promoted substitution from handheld to handsfree phones among drivers who talk on the phone while driving.

PRACTICAL APPLICATIONS

These findings should encourage other states to enact comprehensive handheld phone bans to improve traffic safety.

Bans on Cellphone Use While Driving and Traffic Fatalities in the United States

BACKGROUND

As of January 2020, 18 of 50 US states comprehensively banned almost all handheld cellphone use while driving, 3 states and the District of Columbia banned calling and texting, 27 states banned texting on a handheld cellphone, and 2 states had no general cellphone ban for all drivers. However, it remains unknown whether these bans were associated with fewer traffic deaths and whether comprehensive handheld bans are more effective than isolated calling or texting bans. We evaluated whether cellphone bans were associated with fewer driver, non-driver, and total fatalities nationally.

METHODS

We conducted a longitudinal panel analysis of traffic fatality rates by state, year, and quarter. Population-based rate ratios and 95% CIs were estimated comparing state-quarters with and without cellphone bans.

RESULTS

From 1999 through 2016, 616,289 persons including 344,003 drivers died in passenger vehicle crashes in the United States. Relative to no ban, comprehensive handheld bans were associated with lower driver fatality rates (adjusted rate ratio aRR = 0.93, 95% CI = 0.90, 0.97) but not for non-driver fatalities (aRR = 1.01, 95% CI = 0.95, 1.07) or total fatalities (aRR = 0.98, 95% CI = 0.94, 1.01). We found no differences in driver fatalities for calling-only bans (aRR = 1.00, 95% CI = 0.97, 1.03), texting-only bans (aRR = 1.02, 95% CI = 0.99, 1.05), texting plus phone-manipulating bans (aRR = 0.99, 95% CI = 0.93, 1.04), or calling and texting bans (aRR = 0.98, 95% CI = 0.88, 1.09).

CONCLUSIONS

Comprehensive handheld bans were associated with fewer driver fatalities.

Cellphone laws and teens' calling while driving: analysis of repeated cross-sectional surveys in 2013, 2015, 2017, and 2019

Background

Distracted driving among teens is a public health and safety concern. Most states in the U.S. have sought to restrict cellphone use while driving by enacting laws. This study examines the difference in prevalence of self-reported calling while driving (CWD) between states with different cellphone bans.

Methods

Demographics and CWD data were extracted from state Youth Risk Behavior Surveys (YRBS) from 14 states in 2013, 2015, 2017, and 2019. The state YRBS is conducted every 2 years with a representative sample of 9th through 12th grade students attending public school. States were grouped by type of cellphone law(s): no ban (the absence of both handheld calling ban and young driver ban), young driver ban (a ban on all forms of cellphone use while driving, for young drivers only), or concurrent ban (a young driver ban plus a ban on handheld calling for all drivers irrespective of age). Poisson regression models with robust variance were used to estimate prevalence ratios comparing CWD prevalence across ban types.

Results

In total, 157,423 high school students participated in the surveys, and 65,044 (45%) participants reached the minimum age to obtain an intermediate license and drove during the 30 days prior the survey. Approximately 53% of participants reported CWD at least once during the previous 30 days, and the percentages varied widely by states (range: 51–55%). Compared to students from states with no ban, those from states with concurrent bans were 19%(95% CI: 14–24%) less likely to engage in CWD. Students in states with concurrent bans were 23% less likely to engage in CWD compared to students in states with young driver bans (95% CI:17–27%).

Conclusions

Engaging in CWD is common among teen drivers. The concurrent implementation of a handheld calling ban and a young driver ban was associated with a lower prevalence of CWD.

Supplementary Information

The online version contains supplementary material available at 10.1186/s40621-020-00290-x.

Evaluating the impact of penalising the use of mobile phones while driving on road traffic fatalities, serious injuries and mobile phone use: a systematic review

BACKGROUND

A vast literature has demonstrated that using mobile phones while driving increases the risk of road traffic crashes. In response, policy-makers have introduced bans and harsher penalties on using mobile phones while driving. Even though emerging evidence suggests that such measures may reduce mobile phone use and crashes, the literature has not been systematically reviewed and synthesised.

OBJECTIVE

To evaluate the impact of penalising mobile phone use while driving on road traffic fatalities, serious injuries and the prevalence of mobile phone use while driving.

METHODS

We employed a comprehensive search strategy using electronic databases, websites, handsearching and other sources to locate studies evaluating legislation on mobile phone use while driving. Randomised controlled trials, interrupted time series', controlled before-after studies with control(s) not exposed to harsher sanctions and panel data designs were included if they measured the outcomes of fatalities, serious injuries or the prevalence of mobile phone use while driving. Eligible studies were critically appraised. Due to substantial heterogeneity, the results were synthesised narratively. The synthesis structured studies according to the type of legislation and outcome measure.

RESULTS

Of the 7420 studies retrieved, 32 were included. The evidence on the effects of penalising mobile phone use while driving was weak, and somewhat inconsistent, but pointed to a potential decrease in the prevalence of mobile phone use and fatalities for all-driver primary enforcement hand-held bans and texting bans.

CONCLUSIONS

Preventing fatalities from risky driving practices may be helped by implementing harsher laws that penalise mobile phone use while driving.