The effect of the learner license Graduated Driver Licensing components on teen drivers' crashes

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.

Effectiveness of implementing a Graduated Driver Licensing (GDL) law among young Serbian drivers

INTRODUCTION

Young novice drivers have higher rates of engagement in road crashes worldwide, often owing to unfavorable attitudes toward road safety or lack of knowledge, experience, and risk consciousness. However, the implementation of graduated driver licensing (GDL) systems has proven effective in reducing the high incidence of young drivers involved in crashes.

METHOD

The purpose of this study was to compare the change in driving outcomes (e.g., attitudes toward traffic safety, behavior patterns while driving, risk assessment in traffic, assessment of personal driving skills, and involvement in traffic crashes) of young drivers prior to and following the implementation of a GDL law. Respondents (n = 642) completed a battery of questions, including a driver attitudes questionnaire (Behaviour of Young Novice Drivers Scale), a self-assessed driving ability questionnaire, and a risk perception questionnaire. Of the total sample size, 324 drivers passed the old system of training driver's license candidates, and 318 drivers passed the new GDL system.

RESULTS

The results showed that drivers licensed with GDL reported safer attitudes toward traffic rule violations and speed, and higher levels of safety orientation with regard to their driving abilities. They also reported much higher levels of risk perception and lower exposure to risky situations (risky driving exposure). There were no differences between GDL drivers and non-GDL drivers in terms of self-reported crashes or transient or fixed violations. In addition, GDL was not related to the number of traffic crashes, the number of fatalities, or serious and slight injuries in crashes involving young drivers in crashes obtained from official records.

CONCLUSIONS

The results suggest that GDL contributed to the improvement of drivers' attitudes and understanding of risk but did not contribute to significant changes in the behavior of young drivers and traffic crashes. In addition, the GDL program in Serbia only ranks fair on the Insurance Institute for Highway Safety (IIHS) scale. Strengthening the GDL program in Serbia with additional components in line with GDL programs rated as good by the IIHS scale could improve the safety of young and novice drivers in traffic.

Association of age and severe injury in young motorcycle riders: A cross-sectional study from Karachi, Pakistan

INTRODUCTION

The burden imposed by motorcyclist deaths and injuries is high in low- and middle-income countries. Many injured motorcycle riders in these settings are underage. The aim of this study was to assess the association between age and severe injury in young motorcycle riders.

METHODS

We analysed road traffic injury surveillance data from the emergency rooms of five hospitals in Karachi from 2007 to 2015. We used logistic regression to assess the association of motorcycle riders' age, categorised as underage (13-17 years), early licensing age (18-19 years) and late licensing age (20-24 years), with severe injury, defined as an Injury Severity Score (ISS) ≥ 16.

RESULTS

The study sample included 45,366 motorcycle riders. There were 10115 (22.3%) motorcycle riders aged 13-17 years, 9899 (21.8%) aged 18-19 years and 25352 (55.9%) aged 20-24 years. Almost all were male (99%). Being aged 13-17 years (adjusted odds ratio 1.25; 95% CI 1.11, 1.42) and 18-19 years (adjusted odds ratio 1.26; 95% CI 1.10, 1.43) were associated with higher odds of severe injury compared with being aged 20-24 years.

CONCLUSION

Motorcycle riders who presented to the hospital with injuries after road traffic crashes and were aged 13-17 years and 18-19 years had significantly higher odds of severe injury than those aged 20-24 years.

At what stages of licensing do graduated driver licensing systems reduce crashes? Example from Queensland, Australia

Evaluations of new graduated licensing systems (GLS) commonly examine pre-post young driver crash rates relative to another driver group. This comparison approach is important to account for other influences on crashes over time, but has limited ability to determine which GLS components are most effective and at what stage during the licensing process. We previously identified declines in young driver crashes in Queensland, Australia, following introduction of a new GLS in 2007. The objective of the current research was to conduct complementary modelling to identify at what points through the licensing process had particular GLS policies contributed to reductions. Crash trends were explored for learner and provisional drivers under the new GLS versus previous system for three time periods relative to the month of acquiring a provisional licence: the preceding learner period, the first month of provisional licensure (when crashes typically peak), and the overall provisional period. Interrupted time series analyses were conducted for the log ratio of crashes per 10,000 licensed (learner and provisional) drivers with the total number of licensed drivers as an offset. The greatest declines were found in the first month of licensure, with indications that a longer learner period, higher supervised driving hours, and a new provisional night-passenger restriction were key contributors to provisional crash reductions. There was also some indication that a restriction on all phone use reduced crashes during the learner period. We conclude that time series analysis focusing on licensing stage, rather than calendar time only, offers a complementary approach to analysing GLS effectiveness by better identifying where and how changes impact crashes.

Learner Driver Experience and Teenagers' Crash Risk During the First Year of Independent Driving

IMPORTANCE

One mechanism for teenagers' elevated crash risk during independent driving may be inadequate learner driving experience.

OBJECTIVE

To determine how learner driver experience was associated with crash risk during the first year of independent driving.

DESIGN, SETTING, AND PARTICIPANTS

Youth aged 15.5 to 16.1 years at recruitment were eligible to participate. Participants' vehicles were instrumented with sensors, and driving was recorded during the learner period through 1 year of independent driving. Data were collected from January 2011 through August 2014 in southwestern Virginia.

EXPOSURES

The amount, consistency and variety of practice, driving errors, and kinematic risky driving (KRD) rates during the learner period were recorded. Surveys, including one on sensation-seeking personality traits, were assessed at baseline.

MAIN OUTCOMES AND MEASURES

Cox proportional hazard regressions examined associations between individual characteristics and learner driving experience with driving time to first crash and all crashes in the first year of independent driving. So that hazard ratios (HRs) can be directly comparable, units of measurement were standardized to the interquartile range.

RESULTS

Of 298 individuals who responded to recruitment, 90 fulfilled the criteria and 82 completed the study (of whom 75 were white [91%] and 44 were girls [54%]). Teenage participants drove a mean (SD) of 1259.2 (939.7) miles over 89 days during the learner period. There were 49 property-damage crashes and/or police-reportable crashes during independent driving. Factors associated with driving time to first crash included higher sensation-seeking personality scale scores (HR, 1.67 [95% CI, 1.08-2.57] per 0.75-unit increase), learner driving KRD rates (HR, 1.27 [95% CI, 1.12-1.43] per 9.24-unit increase), and learner driving errors (HR, 0.44 [95% CI, 0.22-0.86] per increase of 6.48 errors). Similar results were obtained for all crashes in the first year, with the addition of consistency of learner driving practice (HR, 0.61 [95% CI, 0.38-0.99] per 0.23-unit increase).

CONCLUSIONS AND RELEVANCE

Individual characteristics and learner driving experiences were associated with crash risk during independent driving. As expected, there was an association between sensation seeking and crashes. Elevated KRD rates during the learner period may reflect risky driving behavior among novices or tolerance to abrupt maneuvers by parents who supervise driving. Consistent practice throughout the learner period could reduce teenage crash risk, which is supported by learning theories indicating distributed practice is effective for developing expertise. Errors during practice may constitute learning events that reinforce safer driving. Physicians could encourage parents to provide opportunities for regular practice driving and monitor their teenager's KRD rates during the learner period using in-vehicle or smartphone-based technology.

Implementation is not enough: Graduated drivers licensing benefits from a comprehensive enforcement, education, and awareness campaigns

BACKGROUND

Graduated drivers license (GDLs) are required in most states. Graduated drivers licenses are intermediate licenses requiring a supervisory period prior to full licensure. Surveys suggests poor acceptance of GDL restrictions high variability in GDL compliance. New Jersey initiated GDLs in 2002 and introduced a comprehensive public health campaign in 2010. This study analyzed the effect of GDL and the campaign on teen driver-related fatalities and hypothesized that implementation alone was insufficient to decrease deaths.

METHODS

Data were analyzed from 1998 to 2016 from New Jersey's Fatal Accident Investigation Unit. In 2005, collaboration with state police added total crash fatalities and teen passenger deaths to the data set. Patterns in data before and after GDL implementation in 2002 and a comprehensive campaign in 2010 were evaluated to determine effects in New Jersey. Paired t tests, analysis of variance, and regression analyses were performed, with p value less than 0.05 considered significant.

RESULTS

Little effect was seen after initiation of GDL, with no change in number of dead teen drivers (44 vs. 49, p > 0.05) or fatal accidents (117 vs.115, p > 0.05) in the 4 years before and after implementation. However, after the comprehensive campaign, decreases are seen in dead teenaged drivers (42 vs. 22, p < 0.005) and total fatal accidents involving teens (107 vs. 61, p < 0.005). Comparing 4 years before and 6 years after the campaign demonstrates decreases in total crash fatalities involving teen drivers (112 vs. 66, p < 0.05) and in the number of dead teenaged passengers in a vehicle operated by another teen (19 vs. 11 p < 0.05).

CONCLUSIONS

Implementation of GDLs alone may not be an effective strategy in decreasing the number of teen fatalities. A multipronged approach combining comprehensive, public-health based campaign with targeted enforcement is necessary to decrease the number of teen driver-related deaths. Additional studies are needed to assess the relationship between decreased death and compliance with GDLs.

LEVEL OF EVIDENCE

Retrospective comparative study, level III.

Preventing distracted driving: A program from initiation through to evaluation

BACKGROUND

Distracted driving(DD) is a public health threat. We initiated a DD program where the objective was to attract parents to a website to download a parent tool box. We report the effectiveness of media strategy.

METHODS

An evidence based interactive DD website was developed which provided a parent tool box. Two different digital media strategies were used. Parent(P)/Teen(T) focus groups were used. Analytics, orders during each media strategy are reported as well the results of the focus group.

RESULTS

There were 73972 visits (>2 min) to the site. The tool box was downloaded/ordered from 10 different countries and 50 states. There were 603 requests via the internet for tools kits, 159 in the first campaign and 444 in the second campaign. Average website time increased from 2.33 min in media campign 1-5.29 min in campaign 2. The focus groups reported the: website was "very useful" in 9/15-P vs 10/15- T.

CONCLUSION

Contextual placement digital advertising and focused social media was more effective in attracting parents to the website, and increased downloads.

LEVEL OF EVIDENCE

III.

TYPE OF STUDY

prospective/retrospective study with economic and valued based evaluations.

Crash Risk and Risky Driving Behavior Among Adolescents During Learner and Independent Driving Periods

PURPOSE

Novice adolescents' crash rates are highly elevated early in licensure, despite substantial practicedriving during the learner period. The objectives of this study were to examine the variability in measures of driving risk among adolescents during the learner and early independent driving periods and evaluate how risk varies by driving experience, gender, time of day, and road surface conditions.

METHODS

Objective driving data were collected in a naturalistic cohort study of 90 adolescent drivers with learner driving permit and 131 experienced adult drivers. Participants' private vehicles were equipped with data acquisition system documenting driving kinematics, miles driven, and video recordings of the driver and the driving environment. Crash/near-crash (CNC) and kinematic risky driving (KRD) rates were calculated during the learner and early independent driving periods by gender (female/male), time of day (day/night), and road surface conditions (wet/dry) for adolescents and adults.

RESULTS

CNC and KRD rates of adolescents were similar to adult drivers during the learner period (CNC: incident rate ratio [IRR] = 1.67, confidence interval [CI] = .98-2.82 and KRD: IRR = 1.04, CI = .78-1.40, respectively), but dramatically higher in the first year of independent driving (CNC: IRR = 6.51, CI = 4.03-10.51 and KRD: IRR = 3.95, CI = 2.96-5.26, respectively), and particularly elevated the first 3months of licensure. Adolescent KRD rates were higher for males than females and invariably higher than adult rates during day and night, wet and dry conditions.

CONCLUSIONS

While the learner driving period was relatively safe for adolescents, the transition to independent driving was typified by a dramatic increase in risk among adolescents that was higher than adult rates overall and under varying driving conditions.

Graduated driver licensing (GDL) in the United States in 2016: A literature review and commentary

This is the sixth in a series of reviews of research on graduated driver licensing (GDL) published in the Journal of Safety Research, the present review covering the period mid-2012 through 2016. In the two decades since GDL programs began to be introduced on a widespread basis in the United States, a vast amount of research has been published. The current review discusses recent research and the present state of knowledge on the following topics: characteristics of the novice driver population; effects of GDL on crashes for ages 16-19; the learner and intermediate periods; night and passenger restrictions; cellphone laws; GDL for older novices; enforcement of GDL rules; and programs attempting to influence GDL compliance and safe driving practices in general. GDL stands out as a successful policy for reducing teen driver crashes and is worth building on to extend its benefits. Strengthening existing GDL programs has the most potential for producing further crash reductions.

Factors Influencing Learner Permit Duration

An increasing number of countries are requiring an extended learner permit prior to independent driving. The question of when drivers begin the learner permit period, and how long they hold the permit before advancing to independent licensure has received little research attention. Licensure timing is likely to be related to "push" and "pull" factors which may encourage or inhibit the process. To examine this question, we recruited a sample of 90 novice drivers (49 females and 41 males, average age of 15.6 years) soon after they obtained a learner permit and instrumented their vehicles to collect a range of driving data. Participants completed a series of surveys at recruitment related to factors that may influence licensure timing. Two distinct findings emerged from the time-to-event analysis that tested these push and pull factors in relation to licensure timing. The first can be conceptualized as teens' motivation to drive (push), reflected in a younger age when obtaining a learner permit and extensive pre-permit driving experience. The second finding was teens' perceptions of their parents' knowledge of their activities (pull); a proxy for a parents' attentiveness to their teens' lives. Teens who reported higher levels of their parents' knowledge of their activities took longer to advance to independent driving. These findings suggest time-to-licensure may be related to teens' internal motivation to drive, and the ability of parents to facilitate or impede early licensure.

The impact of the 2007 graduated driver licensing law in Massachusetts on the rate of citations and licensing in teenage drivers

OBJECTIVE

We recently demonstrated that the 2007 Massachusetts Graduated Driving Licensing (GDL) law decreased the rate of motor vehicle crashes in teenage drivers. To better understand this decrease, we sought to examine the law's impact on the issuance of driving licenses and traffic citations to teenage drivers.

METHODS

Citation and license data were obtained from the Massachusetts Department of Transportation. Census data were obtained from the Census Data Center. Two study periods were defined: pre-GDL (2002-2006) and post-GDL (2007-2012). Two populations were defined: the study population (aged 16-17) and the control population (aged 25-29). The rates of licenses per population were compared pre- vs. post-GDL for the study group. The numbers of total, state, and local citations per population were compared pre- vs. post-GDL for both populations. A sensitivity analysis was performed for the rates of citations using licenses issued as a denominator.

RESULTS

While licenses per population obtained by the study group decreased over the entire period, there was no change in the rate of decrease per year pre- vs. post-GDL (2.0% vs. 1.4%; p=0.6392). In the study population, total, state, and local citations decreased post-GDL (17.8% vs. 8.1%, p<0.0001; 3.7% vs. 2.2%, p<0.0001; 14.1% vs. 5.8%, p<0.0001, respectively). In the control group, total and state citations did not change (26.7% vs. 23.9%, p=0.3606; 9.2% vs. 10.2%, p=0.3404, respectively), and local citations decreased (17.5% vs. 13.7%, p=0.0389). The rates of decrease per year for total, state, and local citations were significantly greater in the study population compared with control (p<0.0001, p=0.0002, p<0.0001, respectively).

CONCLUSIONS

The 2007 GDL law in Massachusetts was associated with fewer traffic citations without a change in the rate of licenses issued to teenagers. These findings suggest that 2007 GDL may be improving driving habits as opposed to motivating teenagers to delay the issuing of licenses.

Injury Prevention as an Integral Part of Health System Reform Efforts: Lessons Learned from Recently Enacted Massachusetts Laws

Abstract-Injury is the leading cause of mortality in people younger than 44 years of age. Injury prevention laws and policies are not only effective in saving lives at a population level but are also remarkably cost-effective compared to most public health interventions. For example, the implementation of a stricter Massachusetts Graduated Driver Licensing Law in 2007 resulted in a very significant and rapid decrease in the rates of motor vehicle crashes of teenager drivers, saved thousands of lives, and resulted in more than $10 million dollars savings in health care costs over 5 years. We therefore suggest that trauma and injury prevention should be made a priority in any attempt at local, regional, or national health system reform.

Quantifying the influence of safe road systems and legal licensing age on road mortality among young adolescents: steps towards system thinking

Based on existing literature, a system thinking approach was used to set up a conceptual model on the interrelationships among the components influencing adolescent road mortality, distinguishing between components at the individual level and at the system level. At the individual level the role of risk behaviour (sometimes deliberate and sometimes from inexperience or other non-deliberate causes) in adolescent road mortality is well documented. However, little is known about the extent to which the 'road system' itself may also have an impact on younger adolescents' road mortality. This, by providing a safe or unsafe road environment for all road users (System-induced exposure) and by allowing access to high-risk vehicles at a young or older age through the legal licensing age. This study seeks to explore these relationships by analysing the extent to which the road mortality of 10 to 17 year olds in various jurisdictions can be predicted from the System-induced Exposure (SiE) in a jurisdiction and from its legal licensing age to drive motor vehicles. SiE was operationalized as the number of road fatalities per 10(5) inhabitants/all ages together, but excluding the 10 to 17 year olds. Data on road fatalities during the years 2001 through 2008 were obtained from the OECD International Road Traffic Accident Database (IRTAD) and from the USA NHTSA's Fatality Analysis Reporting System (FARS) database for 29 early and 10 late licensing jurisdictions. Linear mixed models were fitted with annual 'Adolescent road mortality per capita' for 2001 through 2008 as the dependent variable, and time-dependent 'SiE' and time-independent 'Licensing system' as predictor variables. To control for different levels of motorisation, the time-dependent variable 'Annual per capita vehicle distance travelled' was used as a covariate. Licensing system of a jurisdiction was entered as a categorical predictor variable with late licensing countries as a baseline group. The study found support for the protective effects of SiE on adolescent safety. If SiE increased by one unit, the mortality rate of 10 to 17 year olds increased by 0.487 units. No support was found for a protective effect of late licensing for this age group. Thus, compared to young adolescents who are allowed to drive motor vehicles in early licensing jurisdictions, late licensing does not provide extra protection for pre-license adolescents. This finding is probably the result of the high risks associated with alternative transport modes, such as moped riding and bicycling. Also, the fact that the study only included risks to young adolescents themselves and did not include the risks they might pose to other road users and passengers may have contributed to this finding, because such risks are greater when driving a motor vehicle than riding a moped or a bicycle. Therefore, to advance our understanding of the impact of licensing systems, more study is needed into the benefits of early or late licensing, thereby considering these wider effects as well.

A multinomial logit analysis of risk factors influencing road traffic injury severities in the Erzurum and Kars Provinces of Turkey

A retrospective cross-sectional study is conducted analysing 11,771 traffic accidents reported by the police between January 2008 and December 2013 which are classified into three injury severity categories: fatal, injury, and no injury. Based on this classification, a multinomial logit analysis is performed to determine the risk factors affecting the severity of traffic injuries. The estimation results reveal that the following factors increase the probability of fatal injuries: drivers over the age of 65; primary-educated drivers; single-vehicle accidents; accidents occurring on state routes, highways or provincial roads; and the presence of pedestrian crosswalks. The results also indicate that accidents involving cars or private vehicles or those occurring during the evening peak, under clear weather conditions, on local city streets or in the presence of traffic lights decrease the probability of fatal injuries. This study comprises the most comprehensive database ever created for a Turkish sample. This study is also the first attempt to use an unordered response model to determine risk factors influencing the severity of traffic injuries in Turkey.

Adolescent and young adult health in the United States in the past decade: little improvement and young adults remain worse off than adolescents

Adolescence and young adulthood are unique developmental periods that present opportunities and challenges for improving health. Health at this age can affect health throughout the lifespan. This review has two aims: (1) to examine trends in key indicators in outcomes, behaviors, and health care over the past decade for U.S. adolescents and young adults; and (2) to compare U.S. adolescents and young adults on these indicators. The review also assesses sociodemographic differences in trends and current indicators. Guided by our aims, previous reviews, and national priorities, the present review identified 21 sources of nationally representative data to examine trends in 53 areas and comparisons of adolescents and young adults in 42 areas. Most health and health care indicators have changed little over the past decade. Encouraging exceptions were found for adolescents and young adults in unintentional injury, assault, and tobacco use, and, for adolescents, in sexual/reproductive health. Trends in violence and chronic disease and related behaviors were mixed. Review of current indicators demonstrates that young adulthood continues to entail greater risk and worse outcomes than adolescence. Young adults fared worse on about two-thirds of the indicators examined. Differences among sociodemographic subgroups persisted for both trends and current indicators.

Active transportation: do current traffic safety policies protect non-motorists?

OBJECTIVE

This study investigated the impact that state traffic safety regulations have on non-motorist fatality rates.

METHODS

Data obtained from the National Highway Traffic Safety Administration (NHTSA), the Federal Highway Administration (FHWA), and the National Institute on Alcohol Abuse and Alcoholism (NIAAA) were analyzed through a pooled time series cross-sectional model using fixed effects regression for all 50 states from 1999 to 2009. Two dependent variables were used in separate models measuring annual state non-motorist fatalities per million population, and the natural log of state non-motorist fatalities. Independent variables measuring traffic policies included state expenditures for highway law enforcement and safety per capita; driver cell phone use regulations; graduated driver license regulations; driver blood alcohol concentration regulations; bike helmet regulations; and seat belt regulations. Other control variables included percent of all vehicle miles driven that are urban and mean per capita alcohol consumption per year.

RESULTS

Non-motorist traffic safety was positively impacted by state highway law enforcement and safety expenditures per capita, with a decrease in non-motorist fatalities occurring with increased spending. Per capita consumption of alcohol also influenced non-motorist fatalities, with higher non-motorist fatalities occurring with higher per capita consumption of alcohol. Other traffic safety covariates did not appear to have a significant impact on non-motorist fatality rates in the models.

CONCLUSION

Our research suggests that increased expenditures on state highway and traffic safety and the initiation/expansion of programs targeted at curbing both driver and non-motorist intoxication are a starting point for the implementation of traffic safety policies that reduce risks for non-motorists.

Analysis of factors associated with injury severity in crashes involving young New Zealand drivers

Young people are a risk to themselves and other road users, as motor vehicle crashes are the leading cause of their death. A thorough understanding of the most important factors associated with injury severity in crashes involving young drivers is important for designing well-targeted restrictive measures within youth-oriented road safety programs. The current study estimates discrete choice models of injury severity of crashes involving young drivers conditional on these crashes having occurred. The analysis examined a comprehensive set of single-vehicle and two-vehicle crashes involving at least one 15-24 year-old driver in New Zealand between 2002 and 2011 that resulted in minor, serious or fatal injuries. A mixed logit model accounting for heterogeneity and heteroscedasticity in the propensity to injury severity outcomes and for correlation between serious and fatal injuries proved a better fit than a binary and a generalized ordered logit. Results show that the young drivers' behavior, the presence of passengers and the involvement of vulnerable road users were the most relevant factors associated with higher injury severity in both single-vehicle and two-vehicle crashes. Seatbelt non-use, inexperience and alcohol use were the deadliest behavioral factors in single-vehicle crashes, while fatigue, reckless driving and seatbelt non-use were the deadliest factors in two-vehicle crashes. The presence of passengers in the young drivers' vehicle, and in particular a combination of males and females, dramatically increased the probability of serious and fatal injuries. The involvement of vulnerable road users, in particular on rural highways and open roads, considerably amplified the probability of higher crash injury severity.