Driver distraction research has a long history, spanning nearly 50 years, but intensifying over the last decade. The dominant paradigm guiding this research defines distraction in terms of excessive workload and limited attentional resources. This approach largely ignores how drivers come to engage in these tasks and under what conditions they engage and disengage from driving-the dynamics of distraction. The dynamics of distraction identifies breakdowns of interruption management as an important contributor to distraction, leading to describe distraction in terms of failures of task timing, switching, and prioritization. The dynamics of distraction also identifies disengagement in driving (e.g., mind wandering) as a substantial challenge that secondary tasks might exacerbate or mitigate. Increasing vehicle automation accentuates the need to consider these dynamics of distraction. Automation offers drivers more opportunity to engage in distractions and disengage from driving, and can surprise drivers by unexpectedly requiring drivers to quickly re-engage in driving-placing greater importance of interruption management expertise. This review describes distraction in terms of breakdowns in interruption management and problems of engagement, and summarizes how contingency, conditioning, and consequence traps lead to problems of engaging and disengaging in driving and distractions.
Novice teen drivers have long been known to have an increased risk of crashing, as well as increased tendencies toward unsafe and risky driving behaviors. Teens are unique as drivers for several reasons, many of which have implications specifically in the area of distracted driving. This paper reviews several of these features, including the widespread prevalence of mobile device use by teens, their lack of driving experience, the influence of peer passengers as a source of distraction, the role of parents in influencing teens' attitudes and behaviors relevant to distracted driving and the impact of laws designed to prevent mobile device use by teen drivers. Recommendations for future research include understanding how engagement in a variety of secondary tasks by teen drivers affects their driving performance or crash risk; understanding the respective roles of parents, peers and technology in influencing teen driver behavior; and evaluating the impact of public policy on mitigating teen crash risk related to driver distraction.
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.
A variety of methodologies for understanding the prevalence of distracted driving, its risk, and other aspects of driver secondary activity, have been used in the last 15 years. Although the current trend is toward naturalistic driving studies, each methodology contributes certain elements to a better understanding that could emerge from a convergence of these efforts. However, if differing methods are to contribute to a common and robust understanding of driver distraction, it is critical to understand the strengths and limitations of each method. This paper reviews several of the non-naturalistic methods. It suggests that "convergence science" - a more concerted and rigorous effort to bring different approaches together into an integrative whole - may offer benefits for identification and definition of issues and countermeasure development to improve driving safety.
By using in situ naturalistic driving data, estimates of prevalence and risk can be made regarding driver populations' secondary task distractions and crash rates. Through metadata analysis, three populations of drivers (i.e., adult light vehicle, teenaged light vehicle, and adult heavy vehicle) were compared regarding frequency of secondary task behavior and the associated risk for safety-critical incidents. Relative risk estimates provide insight into the risk associated with engaging in a single task. When such risk is considered in combination with frequency of use, it sheds additional light on those secondary tasks that create the greatest overall risk to driving safety. The results show that secondary tasks involving manual typing, texting, dialing, reaching for an object, or reading are dangerous for all three populations. Additionally, novice teen drivers have difficulty in several tasks that the other two populations do not, including eating and external distractions. Truck drivers also perform a number of risky "mobile office" types of tasks, including writing, not seen in the other populations. Implications are described for policy makers and designers of in-vehicle and nomadic, portable systems.
There is little agreement in the scientific literature about what the terms "driver distraction" and "driver inattention" mean, and what the relationship is between them. In 2011, Regan, Hallett and Gordon proposed a taxonomy of driver inattention in which driver distraction is conceptualized as just one of several processes that give rise to driver inattention. Since publication of that paper, two other papers have emerged that bear on the taxonomy. In one, the Regan et al taxonomy was used, for the first time, to classify data from an in-depth crash investigation in Australia. In the other, another taxonomy of driver inattention was proposed and described. In this paper we revisit the original taxonomy proposed by Regan et al. in light of these developments, and make recommendations for how the original taxonomy might be improved to make it more useful as a tool for classifying and coding crash and critical incident data. In addition, we attempt to characterize, theoretically, the processes within each category of the original taxonomy that are assumed to give rise to driver inattention. Recommendations are made for several lines of research: to further validate the original taxonomy; to understand the impact of each category of inattention in the taxonomy on driving performance, crash type and crash risk; and to revise and align with the original taxonomy existing crash and incident investigation protocols, so that they provide more comprehensive, reliable and consistent information regarding the contribution of inattention to crashes of all types.
Sources of distraction are numerous and varied, and defining and measuring distraction and attention is complicated. The driving task requires constant adjustments and reallocation of attention to cognitive, motor, and visual processes. While it is fairly straightforward to measure distraction in an experimental situation (e.g., simulator, closed course), driver distraction in the real world is highly contextual. While no single metric is capable of capturing the complexities of distraction, several have proved useful in helping researchers gain fuller understanding of it. Few have reached a level of consensus among researchers and user interface designers. ISO and SAE may be considered the 'gold standard' for providing mechanisms through which open scientific consensus-based standards can be achieved.While there are a number of metrics used in predicting distraction, three have been studied closely and are going through the SAE and ISO standards process. They are (1) 'the occlusion method'; (2) the Lane Change Test (LCT); and (3) the Detection Response Task (DRT). The metrics described here apply generally to the experimental context where driving is tightly controlled. Like any method, there are limitations with each-and they don't necessarily agree with one another.Experimental methods and analyses are different than those in naturalistic driving (ND). ND relies more on data mining versus traditional experimental manipulation. ND data are a challenge precisely in that they lack experimental control.In future, driver metrics will go beyond specific measurement of task load, and will include how drivers self regulate when they choose to be distracted.
In this article we develop a model of the relationship between crash risk and a driver's situation awareness. We consider a driver's situation awareness to reflect the dynamic mental model of the driving environment and to be dependent upon several psychological processes including Scanning the driving environment, Predicting and anticipating hazards, Identifying potential hazards in the driving scene as they occur, Deciding on an action, and Executing an appropriate Response (SPIDER). Together, SPIDER is important for establishing and maintaining good situation awareness of the driving environment and good situation awareness is important for coordinating and scheduling the SPIDER-relevant processes necessary for safe driving. An Order-of-Processing (OP) model makes explicit the SPIDER-relevant processes and how they predict the likelihood of a crash when the driver is or is not distracted by a secondary task. For example, the OP model shows how a small decrease in the likelihood of any particular SPIDER activity being completed successfully (because of a concurrent secondary task performance) would lead to a large increase in the relative risk of a crash.
Distracted driving has burgeoned with the proliferation of cell phones, global positioning systems and other in-vehicle and personal electronic devices. Annually more than 3,300 people are killed and an additional 400,000 are injured in the United States in distracted driving crashes. The United States (U.S.) federal and state governments have responded to this public health problem with policies and laws; however, a more comprehensive and more effective approach is still needed. Some restrictions on the use of electronic devices while driving by federal employees and some voluntary guidelines and recommendations have been issued. Public opinion polls show support for addressing the issue of distracted driving with state laws. The majority of states have laws banning text messaging while driving and prohibiting the use of an electronic device by teenage or novice drivers. Some states prohibit all drivers from using a hand-held cellphone. Currently no state has a total ban on the use of personal electronic devices while driving. Successful past traffic safety campaigns changing driver behavior have demonstrated the necessity to adopt a “three Es” approach of Enactment of a law, Education of the public about the law, and rigorous Enforcement of the law. Experience reveals that this approach, along with future federal regulation of in-vehicle electronic devices and the employment of technology to limit the use of electronic devices while driving, is needed to alter personal behavior in order to reduce distractions and keep drivers focused on the driving task.
Interurban road crashes often result in severe Road Traffic Injuries (RTIs). Prehospital emergency care on interurban roads was rarely evaluated in the low- and middle-income countries. The study highlighted the availability and quality of prehospital care facilities on interurban roads in Pakistan, a low-income country. The study setting was a 592-km-long National highway in the province of Sindh, Pakistan. Using the questionnaires adapted from the World Health Organization prehospital care guidelines [Sasser et al., 2005], managers and ambulance staff at the stations along highways were interviewed regarding the process of care, supplies in ambulances, and their experience of trauma care. Ambulance stations were either managed by the police or the Edhi Foundation (EF), a philanthropic organization. All highway stations were managed by the EF; the median distance between highway stations was 38 km (Interquartile Range [IQR]=27-46). We visited 14 stations, ten on the highway section, and four in cities, including two managed by the police. Most highway stations (n=13) received one RTI call per day. Half of stations (n=5) were inside highway towns, usually near primary or secondary-level healthcare facilities. Travel time to the nearest tertiary healthcare facility ranged from 31 to 70 minutes (median=48 minutes; IQR=30-60). Other shortcomings noted for stations were not triaging RTI cases (86%), informing hospitals (64%), or recording response times (57%). All ambulances (n=12) had stretchers, but only 58% had oxygen cylinders. The median schooling of ambulance staff (n=13) was 8 years (IQR=3-10), and the median paramedic training was 3 days (IQR=2-3). Observed shortcomings in prehospital care could be improved by public-private partnerships focusing on paramedic training, making available essential medical supplies, and linking ambulance stations with designated healthcare facilities for appropriate RTI triage.
The study purpose was to develop mortality-based metrics of injury severity for frequent motor vehicle crash (MVC) injuries. Injury severity was quantified with mortality-based metrics for 240 injuries comprising the top 95% most frequently occurring AIS 2+ injuries in the National Automotive Sampling System - Crashworthiness Data System (NASS-CDS) 2000-2011. Mortality risk ratios (MRRs) were computed by dividing the number of deaths by occurrences for each of the 240 injuries using National Trauma Data Bank Research Data System (NTDB-RDS) MVC cases. MRRMAIS was computed using only patients with a maximum AIS (MAIS) equal to the AIS severity of a given injury. Each injury had an associated MRR and MRRMAIS which ranged from zero (0% mortality representing low severity) to one (100% or universal mortality representing high severity). Injuries with higher MRR and MRRMAIS values are considered more severe because they resulted in a greater proportion of deaths among injured patients. The results illustrated an overall positive trend between AIS severity and the MRR and MRRMAIS values as expected, but showed large variations in MRR and MRRMAIS for some injuries of the same AIS severity. Mortality differences up to 83% (MRR) and 54% (MRRMAIS) were observed for injuries of the same AIS severity. The MRR-based measures of injury severity indicate that some lower AIS severity injuries may result in as many deaths as higher AIS severity injuries. This data-driven determination of injury severity using MRR and MRRMAIS provides a supplement or an alternative to AIS severity classification.
We investigated the effects of speed cameras along a 26 mile segment in metropolitan Phoenix, Arizona. Motor vehicle collisions were retrospectively identified according to three time periods - before cameras were placed, while cameras were in place and after cameras were removed. A 14 mile segment in the same area without cameras was used for control purposes. Five cofounding variables were eliminated. In this study, the placement or removal of interstate highway speed cameras did not independently affect the incidence of motor vehicle collisions.
Biplane x-ray was used to image two cadavers in upright and inverted postures, and the three-dimensional variation in the relative abdominal organ position was quantified. The abdominal organs of each surrogate were instrumented with radiopaque markers using a minimally invasive approach. Imaging was performed with a known stomach volume, with residual air removed from the abdominal cavity, and with ventilation and perfusion. Marker positions were determined in two planar x-ray perspectives using target tracking software and projected into calibrated three-dimensional coordinates. Intuitive changes in organ position were observed with the effect of gravity in the upright orientation; in the superior-inferior direction, the separation between the most cranial and caudal diaphragm and liver markers was 95 mm to 169 mm. When inverted, the abdominal organs shifted cranially and fell within 66 to 81 mm in the superior-inferior direction. The relative change in position of the diaphragm markers, determined as the vector magnitude from the upright to the inverted position, was 99 to 121 mm. These data were scaled and compared to positional MRI data from nine human subjects in seated postures and the Global Human Body Models Consortium (GHBMC) model geometry. The overall shapes and relative positions of the inverted cadaver organs compared better to the human subjects and model geometry. These results give rise to several issues for consideration when interpreting cadaver test results and comparing them to finite element simulations and their associated injury prediction abilities.
Two common methods used to assign driver responsibility for a motor vehicle crash are based either on the issuance of a citation for a moving violation or the presence of a crash-contributing driver action. The objective of this study was to understand the practical implications of using these alternative methods, in particular in the context of young driver crashes. The study population included all drivers involved in a police-reported crash with a driver under the age of 21 between January 1, 2010 through December 31, 2011 (n=140,840). The authors conclude that this study demonstrates the potential for general underestimation of at-fault crash involvement among drivers involved in young driver crashes when citation data are utilized to determine fault. Further, the extent of this underestimation is not constant across subgroups for many driver demographic and crash-related factors and thus may lead to statistical bias of relative estimates comparing at-fault crash involvement among subgroups.
There is very little known about the differences in the immediate crash environment of teen and adult crashes. The authors aimed to: identify the most frequent “crash scenarios” — vehicle’s movement prior to crash, immediate pre-crash event, and crash configuration — among teen drivers in serious crashes; compare these frequencies with those of adult drivers; and, for each crash scenario, compare the critical reason (i.e. the single most important proximate reason) for teens’ and adults’ crashes. They analyzed data on 642 16- to 19-year-old and 1,167 35- to 54-year-old licensed drivers who were involved in serious crashes (i.e., required EMS response) in the National Motor Vehicle Crash Causation Survey (2005–07) and who were assigned a driver-related critical reason (i.e., critical error) for their crash. The authors conclude that several specific crash scenarios highlighted the increased contribution of decision errors among teen drivers.
Since 1996, states have been implementing and enhancing their graduated driver licensing (GDL) programs. Increased licensing restrictions could steer new drivers to bypass training and licensing altogether. Unlicensed driving is associated with increased fatal crashes and high-risk behaviors that have been shown to adversely affect passenger safety behaviors like restraint use. The objective of this study was to assess the impact of varying state level GDL programs on rates of unlicensed driving and on passenger restraint use. De-identified data from the National Highway Traffic Safety Administration's Fatality Analysis Reporting System from years 1996-2010 was analyzed. Fatal crashes involving drivers (15-24 yrs) and their passengers (15-24 yrs) were included. Using a validated system, each state's GDL laws at a given month were rated as poor, marginal, fair, or good. The association between GDL strength and unlicensed driving was analyzed graphically and by chi-square test. Multivariate logistic regression with generalized estimating equations were undertaken to assess the relationship between GDL strength and passenger restraint use. From January 1996 to December 2010, 26,504 (23.4%) passengers were involved in fatal crashes taking place in states with GDL programs rated poor, 21,366(18.9%) marginal, 33,603 (29.6%) fair, and 31,903 (28.1%) good. Rates of unlicensed driving ranged from 16.4% in state-months rated marginal versus 21.5% in state-months rated good (p<0.001). In the multivariate model, compared to states with poor GDL ratings, each additional rating boost was associated with an increased odds of passenger safety restraint use (OR 1.15, 95% CI 1.13-1.18). Our findings suggest that stronger GDL law can mitigate passenger risk in fatal crashes by encouraging passenger restraint use. Our study provides evidence that stronger legislation in these states may reduce overall risk to young drivers and their passengers.
Many researchers have made efforts to identify the causation of whiplash associated disorders (WAD) in rear-end collisions. Based on their work, the safety features for rear crash protection have been developed, and also the assessment methodology using BioRID II dummy has been established worldwide. Consequently, the design of passenger car seat has been improved to prevent WAD; however, WAD has been still reported at a very low-speed rear collision in South Korea. The aim of this study is to quantify the dynamic responses of middle-aged Korean males in a low-speed rear impact, and to compare with the results from the previous studies to provide basic resources for further research. Motion analysis shows the major factor that affected the difference in dynamic responses is the size of body. The dummy improvement is needed to be designed to consider smaller occupants than BioRID II. For future studies, various factors such as the posture, seat configuration, and the effect of bracing should be taken into consideration.
Injury risk assessment plays a pivotal role in the assessment of the effectiveness of Advanced Driver Assistance Systems (ADAS) as they specify the injury reduction potential of the system. The usual way to describe injury risks is by use of injury risk functions, i.e. specifying the probability of an injury of a given severity occurring at a specific technical accident severity (collision speed). A method for the generation of a family of risk functions for different levels of injury severity is developed. The injury severity levels are determined by use of a rescaled version of the Injury Severity Score (ISS) namely the ISSx. The injury risk curves for each collision speed is then obtained by fixing the boundary conditions and use of a case-by-case validated GIDAS subset of pedestrian-car accidents (N=852). The resultant functions are of exponential form as opposed to the frequently used logistic regression form. The exponential approach in combination with the critical speed value creates a new injury risk pattern better fitting for high speed/high energy crashes. Presented is a family of pedestrian injury risk functions for an arbitrary injury severity. Thus, the effectiveness of an ADAS can be assessed for mitigation of different injury severities using the same injury risk function and relying on the internal soundness of the risk function with regard to different injury severity levels. For the assessment of emergency braking ADAS, a Zone of Effective Endangerment Increase (ZEEI), the speed interval in which a one percent speed increase results at least in a one percent of injury risk increase, is defined. The methodology presented is kept in such general terms that a direct adaption to other accident configurations is easily done.
The purpose of this study was to compare the dynamic response of rear-facing child restraint systems (RFCRS) installed on the CMVSS 213 sled bench and a selection of vehicle seats. Thirty-six sled tests were conducted: three models of rear facing CRS with an anthropomorphic test device (ATD) representing a 12 month old child (CRABI) were affixed via lower anchors (LATCH), 3 point belt without CRS base, and 3 point belt with CRS base to one of three vehicle seats or the CMVSS 213 bench seat. All CRS were subjected to an identical sled acceleration pulse. Two types of matched pair analysis: "bench-to-vehicle" and "method of attachment" were conducted. Statistically significant differences were observed in the kinematic responses of the ATD and the CRS.This is the first study to quantify differences between the regulatory bench and vehicle seats on a system level and evaluate the influence of attachment method. Our results show that the difference in RFCRS forward excursion between 3-point belt with base and LATCH installations was between 1 and 7 percent on the bench and 22 to 76 percent on the vehicle seats. When evaluating the dynamic performance of RFCRS, the use of real vehicle seats from vehicles that commonly carry children may provide valuable insight. The findings would require further confirmation using a broader selection of RFCRS and vehicle seats, before generalizable conclusions can be drawn.
