Driver performance while texting: even a little is too much

Driver distraction and in-vehicle interventions: A driving simulator study on visual attention and driving performance

Driving simulator studies are popular means to investigate driving behaviour in a controlled environment and test safety-critical events that would otherwise not be possible in real-world driving conditions. While several factors affect driving performance, driving distraction has been emphasised as a safety-critical issue across the globe. In this context, this study explores the impact of distraction imposed by mobile phone usage, i.e., writing and reading text messages, on driver behaviour. As part of the greater i-DREAMS project, this study uses a car driving simulator experimental design in Germany to investigate driver behaviour under various conditions: (I) monitoring scenario representing normal driving conditions, (II) intervention scenario in which drivers receive fixed timing in-vehicle intervention in case of unsafe driving manoeuvres, and (III) distraction scenario in which drivers receive in-vehicle interventions based on task completion capability, where mobile phone distraction is imposed. Besides, eye-tracking glasses are used to further explore drivers' attention allocation and eye movement behaviour. This research focuses on driver response to risky traffic events (i.e., potential pedestrian collisions, and tailgating) and the impact of distraction on driving performance, by analysing a set of eye movement and driving performance measures of 58 participants. The results reveal a significant change in drivers' gaze patterns during the distraction drives with significantly higher gaze points towards the i-DREAMS intervention display (the utilised advanced driver assistance systems in this study). The overall statistical analysis of driving performance measures suggests nearly similar impacts on driver behaviour during distraction drives; a higher deviation of lateral positioning was noted irrespective of the event risk levels and lower longitudinal acceleration rates were observed for pedestrian collisions and non-critical events during distracted driving.

Texting While Driving: A Literature Review on Driving Simulator Studies

Road safety is increasingly threatened by distracted driving. Studies have shown that there is a significantly increased risk for a driver of being involved in a car crash due to visual distractions (not watching the road), manual distractions (hands are off the wheel for other non-driving activities), and cognitive and acoustic distractions (the driver is not focused on the driving task). Driving simulators (DSs) are powerful tools for identifying drivers' responses to different distracting factors in a safe manner. This paper aims to systematically review simulator-based studies to investigate what types of distractions are introduced when using the phone for texting while driving (TWD), what hardware and measures are used to analyze distraction, and what the impact of using mobile devices to read and write messages while driving is on driving performance. The review followed the Preferred Reporting Items for Systematic Reviews and Meta-Analysis extension for Scoping Reviews (PRISMA-ScR) guidelines. A total of 7151 studies were identified in the database search, of which 67 were included in the review, and they were analyzed in order to respond to four research questions. The main findings revealed that TWD distraction has negative effects on driving performance, affecting drivers' divided attention and concentration, which can lead to potentially life-threatening traffic events. We also provide several recommendations for driving simulators that can ensure high reliability and validity for experiments. This review can serve as a basis for regulators and interested parties to propose restrictions related to using mobile phones in a vehicle and improve road safety.

Talking on the Phone While Driving: A Literature Review on Driving Simulator Studies

Distracted driving is a growing concern around the world and has been the focus of many naturalistic and simulator-based studies. Driving simulators provide excellent practical and theoretical help in studying the driving process, and considerable efforts have been made to prove their validity. This research aimed to review relevant simulator-based studies focused on investigating the effects of the talking-on-the-phone-while-driving distraction on drivers' behavior. This work is a scoping review which followed the Preferred Reporting Items for Systematic Reviews and Meta-Analysis Extension for Scoping Reviews (PRISMA-ScR) guidelines. The search was performed on five databases, covering twenty years of research results. It was focused on finding answers to three research questions that could offer an overview of the main sources of distraction, the research infrastructure, and the measures that were used to analyze and predict the effects of distractions. A number of 4332 studies were identified in the database search, from which 83 were included in the review. The main findings revealed that TPWD distraction negatively affects driving performance, exposing drivers to dangerous traffic situations. Moreover, there is a general understanding that the driver's cognitive, manual, visual, and auditory resources are all involved, to a certain degree, when executing a secondary task while driving.

The mere presence of a mobile phone: Does it influence driving performance?

The ubiquity of mobile phones has led to a rapid increase in its presence and use in vehicles, especially among young adults (up to 25 years), who are generally the least experienced group of drivers. The potential for phones to draw attention away from the main driving task has significant consequences for road safety. Previous studies have found that the mere presence of a mobile phone can be distracting by impairing attention in experimental non-driving contexts. However, the effect of phone presence, independent to usage, has not yet been examined in the context of driving. As such, the present study examined whether the mere presence of a mobile phone, its proximity to the driver, and power status (on/off) influenced the driving performance of young drivers. Additionally, this study assessed whether the effects of phone presence and proximity were moderated by an individual's level of dependence on, or emotional attachment to, their phone. A sample of 127 undergraduate psychology students (M = 19.76, SD = 1.63) were randomly assigned to one of four conditions: (1) phone absent (control), (2) phone on, in holder, (3) phone off, in holder, and (4) phone on, in pocket. They all completed the same simulated drive, and were measured for degree of phone dependence and phone emotional attachment. Overall, drivers in all the phone present conditions made significantly more driving errors (speeding and collision) compared to those in the phone absent (control) condition, irrespective of proximity to the phone and whether it was on or off. Phone dependence, but not phone emotional attachment, moderated the effect of phone presence on speeding behaviour. These findings suggest that the mere presence of a phone is distracting for drivers, especially so for those who are highly dependent on their phone, which may place them at a greater risk of a distraction induced crash.

Mobile phone use intention while driving among public service vehicle drivers: Magnitude and its social and cognitive determinants

Despite its risks for accident and illegality, little is known about the magnitude and associated social and cognitive factors that motivate drivers to use mobile phone while driving. The present study, guided by theory of planned behavior, aimed at describing the magnitude of mobile use while driving and examining the role of attitudes, subjective norms, perceived behavioral control, and risk perceptions in predicting drivers' intentions to use mobile phone while driving. A total of 155 public service vehicle drivers, who were selected from Debre Markos Town and its vehicle terminal took part in the study. To select study participants, systematic random sampling technique was employed. The instrument used to collect data was self-report questionnaire. The results indicated that more than two-third (69%) of the participants used their mobile phone while driving over the past week. Hierarchical regression analysis displayed that perceived behavioral control, risk perception, and attitude were found to be the most significant social and cognitive predictors of public service vehicle drivers' intention to use mobile phone while driving, but not age and subjective norm variables. So as to reduce drivers' intention to use mobile phone while driving, intervention strategies should focus on enhancing their confidence to avoid this behavior; alerting drivers to the traffic control regulation and the dangers of using mobile phones while driving.

Investigating in-vehicle distracting activities and crash risks for young drivers using structural equation modeling

Distracted driving has been considered one of the main reasons for traffic crashes in recent times, especially among young drivers. The objectives of this study were to identify the distracting activities in which young drivers engage, assess the most distracting ones based on their experiences, and investigate the factors that might increase crash risk. The data were collected through a self-report questionnaire. Most participants reported frequent cell phone use while driving. Other reported activities include adjusting audio devices, chatting with passengers, smoking, eating, and drinking. A structural equation model was constructed to identify the latent variables that have a significant influence on crash risk. The analysis showed that in-vehicle distractions had a high effect on the crash likelihood. The results also indicated that dangerous driving behavior had a direct effect on the crash risk probability, as well as on the rash driving latent variables. The results provide insight into distracted driving behavior among young drivers and can be useful in developing enforcement and educational strategies to reduce this type of behavior.

"I Snapchat and Drive!" A mixed methods approach examining snapchat use while driving and deterrent perceptions among young adults

This research utilised a qualitative and quantitative study to examine a sample of young drivers' perceptions of deterrent forces, both legal and non-legal, for the behaviour of phone use while driving. First, focus groups were conducted with 60 drivers between the ages of 17 and 25 years who resided in Queensland, Australia. This qualitative study utilised an inductive approach to elicit participants' perceptions without omitting important ideas. Legal sanctions were associated with low perceptions of enforcement certainty. Meanwhile, the only non-legal sanction to emerge was the concept of "safety"; many participants were deterred from using their phone while driving for fear of injury or death to themselves or others. The types of social media most likely to be engaged in were explored and sending videos or photos via the application Snapchat emerged as the most common social media application used among the sample. Consequently, the subsequent quantitative study focused on deterrent forces associated with Snapchat use while driving. A survey was utilised with a separate sample of young drivers aged 17-25 years (n = 503). The impact of the threat of legal sanctions on Snapchat use while driving was examined through classical deterrence theory and Stafford and Warr's (1993) reconceptualised deterrence theory. The non-legal factor of perceived safety was also included in the quantitative study. None of the classical deterrence variables (e.g., certainty, severity and swiftness) reached significance while all the reconceptualised deterrence variables (e.g., direct and indirect punishment and punishment avoidance), as well as perceived safety, were significant predictors of Snapchat use while driving. It is suggested that perceptions of certainty of apprehension need to be increased for phone use while driving. The findings show the current impact of deterrent initiatives for phone use while driving as well as provide the first examination of deterrents for the specific mobile phone behaviour of Snapchat use while driving.

Effects of cognitive distraction on speed control in curve negotiation

Objective: Maintaining a lower speed is recommended for curve negotiation and it has been shown that cognitive distraction may impair driving performance. This study examines the effects of different levels of cognitive distraction on the speed control of drivers negotiating a curve. Methods: Experiments were conducted on a 6 degrees of freedom driving simulator with 28 participants. A comparison of the speed and acceleration from 300 m before to 100 m after the curve was performed for baseline driving (without distraction) and 3 levels of cognitive distractions using n-back tasks. Results: The speed was significantly higher at the highest level of cognitive distraction (8%) than in baseline driving from the beginning of the curve to 50 m after it and the ratio of the highest level to the baseline was even greater throughout the range. The average acceleration was significantly higher than the baseline at the highest and the medium levels (80 and 70%, respectively) from 250 m before the curve to the one-quarter curve and from 250 to 150 m before the curve, respectively. It was also found that the point of deceleration was significantly delayed at the highest level of cognitive distraction and occurred only after the middle of the curve, whereas deceleration in baseline driving occurred just before entering the curve. Conclusions: The impairment due to cognitive distraction was confirmed in this study but was only significant at a high level of cognitive distraction. The highly distracted drivers failed to perceive the curve in advance, resulting in a slower response to changes in the roadway. The findings indicate that acceleration may be an indicator of cognitive distraction while negotiating curves. A driver is prone to cognitive distraction and the driving performance is affected when driving requires excessive attention such as curve negotiation.

Effect of Using Mobile Phones on Driver's Control Behavior Based on Naturalistic Driving Data

Distracted driving behaviors are closely related to crash risk, with the use of mobile phones during driving being one of the leading causes of accidents. This paper attempts to investigate the impact of cell phone use while driving on drivers' control behaviors. Given the limitation of driving simulators in an unnatural setting, a sample of 134 cases related to cell phone use during driving were extracted from Shanghai naturalistic driving study data, which provided massive unobtrusive data to observe actual driving process. The process of using mobile phones was categorized into five operations, including dialing, answering, talking and listening, hanging up, and viewing information. Based on the concept of moving time window, the variation of the intensity of control activity, the sensitivity of control operation, and the stability of control state in each operation were analyzed. The empirical results show strong correlation between distracted operations and driving control behavior. The findings contribute to a better understanding of drivers' natural behavior changes with using mobiles, and can provide useful information for transport safety management.

What is the difference in driver's lateral control ability during naturalistic distracted driving and normal driving? A case study on a real highway

Driver distraction is widely recognized as a major contributor to traffic crashes. Although the effect of distraction on simulated driving performance has been studied extensively, comparatively little research based on field tests has been performed on the effects of high driving speeds on lateral driving performance during naturalistic distraction (the driver was unaware of the research topic). In this study, an instrumented vehicle is used to examine the impact of speed and naturalistic visual distraction (rear vehicle's velocity and relative distance estimation) on a driver's ability to keep in the lane. Similar to results from previous studies, visual distraction resulted in an impaired ability to keep in a lane compared to normal driving. Further investigation of steering control parameters showed an increase in steering wheel reversal rates (SRRs at 1.3° and 2.5° levels) and the standard deviation of steering wheel acceleration (SDSWA). The results of this study indicated that the standard deviation of lane positioning (SDLP) and trajectory offset (TO) increased as speed increased. As speed increased, the growth rates of SDLP and TO in the visual distraction task were the same as that in normal driving. Moreover, the SRRs and steering wheel acceleration (SWA) decreased with increased speed. As speed increased, the growth rates of SRRs and SWA during a visual distraction task were the same as that during normal driving. These results suggest that driving speed has a similar effect on driving performance during both distracted driving and normal driving.

Visualization and analysis of mapping knowledge domain of road safety studies

Mapping knowledge domain (MKD) is an important application of visualization technology in Bibliometrics, which has been extensively applied in psychology, medicine, and information science. In this paper we conduct a systematic analysis of the development trend on road safety studies based on the Science Citation Index Expanded (SCIE) and Social Sciences Citation Index (SSCI) articles published between 2000 and 2018 using the MKD software tools VOSviewer and Sci2 Tool. Based on our analysis, we first present the annual numbers of articles, origin countries, main research organizations and groups as well as the source journals on road safety studies. We then report the collaborations among the main research organizations and groups using co-authorship analysis. Furthermore, we adopt the document co-citation analysis, keywords co-occurrence analysis, and burst detection analysis to visually explore the knowledge bases, topic distribution, research fronts and research trends on road safety studies. The proposed approach based on the visualized analysis of MKD can be used to establish a reference information and research basis for the application and development of methods in the domain of road safety studies. In particular, our results show that the knowledge bases (classical documents) of road safety studies in the last two decades have focused on five major areas of "Crash Frequency Data Analysis", "Driver Behavior Questionnaire", "Safety in Numbers for Walkers and Bicyclists", "Road Traffic Injury and Prevention", and "Driving Speed and Road Crashes". Among the research topics, the five dominant clusters are "Causation and Injury Severity Analysis of Road Accidents", "Epidemiologic Study and Prevention of Road Traffic Injury", "Intelligent Transportation System and Active Safety", "Young drivers' driving behavior and psychology", and "Older drivers' psychological and physiological characteristics". Finally, the burst keywords in research trends include Cycling, Intelligent Transportation Systems, and Distraction.

Driving behaviour while self-regulating mobile phone interactions: A human-machine system approach

Mobile phone distracted driving is a recurrent issue in road safety worldwide. Recent research on driving behaviour of distracted drivers suggests that in certain circumstances drivers seem to assume safer behaviours while using a mobile phone. Despite a high volume of research on this topic, self-regulation by mobile phone distracted drivers is not well understood as many driving simulator experiments are designed to impose an equal level of distraction to participants being tested for their driving performance. The aim of this research was to investigate the relationship between self-regulatory secondary task performance and driving. By a driving simulator experiment in which participants were allowed to perform their secondary tasks whenever they feel appropriate, the driving performance of 35 drivers aged 18-29 years was observed under three phone conditions including non-distraction (no phone use), hands-free interactions and visual-manual interactions in the CARRS-Q advanced driving simulator. Drivers' longitudinal and lateral vehicle control observed across various road traffic conditions were then modelled by Generalized Estimation Equations (GEE) with exchangeable correlation structure accounting for heterogeneity resulting from multiple observations from the same driver. Results show that the extent of engagement in the secondary task influence both longitudinal and lateral control of vehicles. Drivers who engaged in a large number of hands-free interactions are found to select lower driving speed. In contrast, longer visual-manual interactions are found to result in higher driving speed among drivers self-regulating their secondary task. Among the road traffic conditions, drivers distracted by their self-regulated secondary tasks are found to select lower speeds along the s-curve compared to straight and motorway segments. In summary, the applied human-machine system approach suggests that road traffic demands play a vital role in both secondary task management and driving performance.

Driving after brain injury: Does dual-task modality matter?

BACKGROUND

Virtual reality technology allows neuropsychologists to examine complex, real-world behaviors with high ecological validity and can provide an understanding of the impact of demanding dual-tasks on driving performance.

OBJECTIVE

We hypothesized that a task imposing high cognitive and physical demands (coin-sorting) would result in the greatest reduction in driving maintenance performance.

METHODS

Twenty participants with acquired brain injury and 28 healthy controls were included in the current study. All participants were licensed and drove regularly. Participants completed two standardized VRDS drives: (1) a baseline drive with no distractions, and (2) the same route with three, counterbalanced dual-tasks representing differing demands.

RESULTS

A series of 3 (Task)×2 (Group) ANOVAs revealed that the ABI group tended to go slower than the HC group in the presence of a dual-task, F (1, 111) = 6.24, p = 0.01. Importantly, the ABI group also showed greater variability in speed, F (1, 110) = 10.97, p < 0.01, and lane position, F (1, 108) = 7.81, p < 0.01, an effect driven by dual-tasks with both a cognitive and motor demand.

CONCLUSIONS

These results indicate that long-term driving difficulties following ABI are subtle and likely due to reduced cognitive resources.

Mobile phone use during driving: Effects on speed and effectiveness of driver compensatory behaviour

This study analysed and modelled the effects of conversation and texting (each with two difficulty levels) on driving performance of Indian drivers in terms of their mean speed and accident avoiding abilities; and further explored the relationship between speed reduction strategy of the drivers and their corresponding accident frequency. 100 drivers of three different age groups (young, mid-age and old-age) participated in the simulator study. Two sudden events of Indian context: unexpected crossing of pedestrians and joining of parked vehicles from road side, were simulated for estimating the accident probabilities. Generalized linear mixed models approach was used for developing linear regression models for mean speed and binary logistic regression models for accident probability. The results of the models showed that the drivers significantly compensated the increased workload by reducing their mean speed by 2.62m/s and 5.29m/s in the presence of conversation and texting tasks respectively. The logistic models for accident probabilities showed that the accident probabilities increased by 3 and 4 times respectively when the drivers were conversing or texting on a phone during driving. Further, the relationship between the speed reduction patterns and their corresponding accident frequencies showed that all the drivers compensated differently; but, among all the drivers, only few drivers, who compensated by reducing the speed by 30% or more, were able to fully offset the increased accident risk associated with the phone use.

Evaluation of an in-vehicle monitoring system (IVMS) to reduce risky driving behaviors in commercial drivers: Comparison of in-cab warning lights and supervisory coaching with videos of driving behavior

PROBLEM

Roadway incidents are the leading cause of work-related death in the United States.

METHODS

The objective of this research was to evaluate whether two types of feedback from a commercially available in-vehicle monitoring system (IVMS) would reduce the incidence of risky driving behaviors in drivers from two companies. IVMS were installed in 315 vehicles representing the industries of local truck transportation and oil and gas support operations, and data were collected over an approximate two-year period in intervention and control groups. In one period, intervention group drivers were given feedback from in-cab warning lights from an IVMS that indicated occurrence of harsh vehicle maneuvers. In another period, intervention group drivers viewed video recordings of their risky driving behaviors with supervisors, and were coached by supervisors on safe driving practices.

RESULTS

Risky driving behaviors declined significantly more during the period with coaching plus instant feedback with lights in comparison to the period with lights-only feedback (ORadj=0.61 95% CI 0.43-0.86; Holm-adjusted p=0.035) and the control group (ORadj=0.52 95% CI 0.33-0.82; Holm-adjusted p=0.032). Lights-only feedback was not found to be significantly different than the control group's decline from baseline (ORadj=0.86 95% CI 0.51-1.43; Holm-adjusted p>0.05).

CONCLUSIONS

The largest decline in the rate of risky driving behaviors occurred when feedback included both supervisory coaching and lights.

PRACTICAL APPLICATIONS

Supervisory coaching is an effective form of feedback to improve driving habits in the workplace. The potential advantages and limitations of this IVMS-based intervention program are discussed.

Texting while driving: the development and validation of the distracted driving survey and risk score among young adults

BACKGROUND

Texting while driving and other cell-phone reading and writing activities are high-risk activities associated with motor vehicle collisions and mortality. This paper describes the development and preliminary evaluation of the Distracted Driving Survey (DDS) and score.

METHODS

Survey questions were developed by a research team using semi-structured interviews, pilot-tested, and evaluated in young drivers for validity and reliability. Questions focused on texting while driving and use of email, social media, and maps on cellular phones with specific questions about the driving speeds at which these activities are performed.

RESULTS

In 228 drivers 18-24 years old, the DDS showed excellent internal consistency (Cronbach's alpha = 0.93) and correlations with reported 12-month crash rates. The score is reported on a 0-44 scale with 44 being highest risk behaviors. For every 1 unit increase of the DDS score, the odds of reporting a car crash increases 7 %. The survey can be completed in two minutes, or less than five minutes if demographic and background information is included. Text messaging was common; 59.2 and 71.5 % of respondents said they wrote and read text messages, respectively, while driving in the last 30 days.

CONCLUSION

The DDS is an 11-item scale that measures cell phone-related distracted driving risk and includes reading/viewing and writing subscores. The scale demonstrated strong validity and reliability in drivers age 24 and younger. The DDS may be useful for measuring rates of cell-phone related distracted driving and for evaluating public health interventions focused on reducing such behaviors.

Does early training improve driving skills of young novice French drivers?

The aim of this research was to study drivers' performances and divided attention depending on their initial training. The performances of young novice drivers who received early training, traditionally trained drivers and more experienced drivers were compared during a dual task consisting of a simulated car-following task and a number' parity judgment task. It was expected that, due to their limited driving experience, the young novice drivers would have more difficulty in adequately distributing their attention between the two tasks. Poorer performances by novice drivers than experienced drivers were therefore expected. The results indicate that traditionally trained drivers had more difficulties in speed regulation and maintaining their position in the lane than drivers with early training and experienced drivers. Performance impairment linked to driving inexperience was also found in the secondary task. The results were interpreted regarding the attentional resources involved in driving with a secondary task and supported the positive effects of French early training.

Neurocognitive Correlates of Young Drivers' Performance in a Driving Simulator

PURPOSE

Differences in neurocognitive functioning may contribute to driving performance among young drivers. However, few studies have examined this relation. This pilot study investigated whether common neurocognitive measures were associated with driving performance among young drivers in a driving simulator.

METHODS

Young drivers (19.8 years (standard deviation [SD] = 1.9; N = 74)) participated in a battery of neurocognitive assessments measuring general intellectual capacity (Full-Scale Intelligence Quotient, FSIQ) and executive functioning, including the Stroop Color-Word Test (cognitive inhibition), Wisconsin Card Sort Test-64 (cognitive flexibility), and Attention Network Task (alerting, orienting, and executive attention). Participants then drove in a simulated vehicle under two conditions-a baseline and driving challenge. During the driving challenge, participants completed a verbal working memory task to increase demand on executive attention. Multiple regression models were used to evaluate the relations between the neurocognitive measures and driving performance under the two conditions.

RESULTS

FSIQ, cognitive inhibition, and alerting were associated with better driving performance at baseline. FSIQ and cognitive inhibition were also associated with better driving performance during the verbal challenge. Measures of cognitive flexibility, orienting, and conflict executive control were not associated with driving performance under either condition.

CONCLUSIONS

FSIQ and, to some extent, measures of executive function are associated with driving performance in a driving simulator. Further research is needed to determine if executive function is associated with more advanced driving performance under conditions that demand greater cognitive load.

Distracted Driving, A Major Preventable Cause of Motor Vehicle Collisions: "Just Hang Up and Drive"

For years, public health experts have been concerned about the effect of cell phone use on motor vehicle collisions, part of a phenomenon known as “distracted driving.” The Morbidity and Mortality Weekly Report (MMWR) article “Mobile Device Use While Driving - United States and Seven European Countries 2011” highlights the international nature of these concerns. Recent (2011) estimates from the National Highway Traffic Safety Administration are that 10% of fatal crashes and 17% of injury crashes were reported as distraction-affected. Of 3,331 people killed in 2011 on roadways in the U.S. as a result of driver distraction, 385 died in a crash where at least one driver was using a cell phone. For drivers 15–19 years old involved in a fatal crash, 21% of the distracted drivers were distracted by the use of cell phones. Efforts to reduce cell phone use while driving could reduce the prevalence of automobile crashes related to distracted driving. The MMWR report shows that there is much ground to cover with distracted driving. Emergency physicians frequently see the devastating effects of distracted driving on a daily basis and should take a more active role on sharing the information with patients, administrators, legislators, friends and family.

The influence of drinking, texting, and eating on simulated driving performance

OBJECTIVE

Driving is a complex task and distractions such as using a mobile phone for the purpose of text messaging are known to have a significant impact on driving. Eating and drinking are common forms of distraction that have received less attention in relation to their impact on driving. The aim of this study was to further explore and compare the effects of a variety of distraction tasks (i.e., text messaging, eating, drinking) on simulated driving.

METHODS

Twenty-eight healthy individuals (13 female) participated in a crossover design study involving 3 experimental trials (separated by ≥24 h). In each trial, participants completed a baseline driving task (no distraction) before completing a second driving task involving one of 3 different distraction tasks (drinking 400 mL water, drinking 400 mL water and eating a 6-inch Subway sandwich, drinking 400 mL water and composing 3 text messages). Primary outcome measures of driving consisted of standard deviation of lateral position (SDLP) and reaction time to auditory and visual critical events. Subjective ratings of difficulty in performing the driving tasks were also collected at the end of the study to determine perceptions of distraction difficulty on driving.

RESULTS

Driving tasks involving texting and eating were associated with significant impairment in driving performance measures for SDLP compared to baseline driving (46.0 ± 0.08 vs. 41.3 ± 0.06 cm and 44.8 ± 0.10 vs. 41.6 ± 0.07 cm, respectively), number of lane departures compared to baseline driving (10.9 ± 7.8 vs. 7.6 ± 7.1 and 9.4 ± 7.5 vs. 7.1 ± 7.0, respectively), and auditory reaction time compared to baseline driving (922 ± 95 vs. 889 ± 104 ms and 933 ± 101 vs. 901 ± 103 ms, respectively). No difference in SDLP (42.7 ± 0.08 vs. 42.5 ± 0.07 cm), number of lane departures (7.6 ± 7.7 vs. 7.0 ± 6.8), or auditory reaction time (891 ± 98 and 885 ± 89 ms) was observed in the drive involving the drink-only condition compared to the corresponding baseline drive. No difference in reaction time to visual stimuli was observed between baseline and experimental drives for any of the trial conditions. Participants' subjective ratings indicated that they perceived the texting while driving condition to be the most difficult despite similar magnitudes of impairment observed with the eating while driving condition.

CONCLUSIONS

Distracting behaviors such as eating and texting while driving appear to negatively impact driving measures of lane position control and reaction time. These findings may have direct implications for motorists that engage in these types of distracting behaviors behind the wheel and for the safety of other road users.

A meta-analysis of the effects of texting on driving

Text messaging while driving is considered dangerous and known to produce injuries and fatalities. However, the effects of text messaging on driving performance have not been synthesized or summarily estimated. All available experimental studies that measured the effects of text messaging on driving were identified through database searches using variants of "driving" and "texting" without restriction on year of publication through March 2014. Of the 1476 abstracts reviewed, 82 met general inclusion criteria. Of these, 28 studies were found to sufficiently compare reading or typing text messages while driving with a control or baseline condition. Independent variables (text-messaging tasks) were coded as typing, reading, or a combination of both. Dependent variables included eye movements, stimulus detection, reaction time, collisions, lane positioning, speed and headway. Statistics were extracted from studies to compute effect sizes (rc). A total sample of 977 participants from 28 experimental studies yielded 234 effect size estimates of the relationships among independent and dependent variables. Typing and reading text messages while driving adversely affected eye movements, stimulus detection, reaction time, collisions, lane positioning, speed and headway. Typing text messages alone produced similar decrements as typing and reading, whereas reading alone had smaller decrements over fewer dependent variables. Typing and reading text messages affects drivers' capability to adequately direct attention to the roadway, respond to important traffic events, control a vehicle within a lane and maintain speed and headway. This meta-analysis provides convergent evidence that texting compromises the safety of the driver, passengers and other road users. Combined efforts, including legislation, enforcement, blocking technologies, parent modeling, social media, social norms and education, will be required to prevent continued deaths and injuries from texting and driving.

Adolescence, attention allocation, and driving safety

Motor vehicle crashes are the leading source of morbidity and mortality in adolescents in the United States and the developed world. Inadequate allocation of attention to the driving task and to driving hazards are important sources of adolescent crashes. We review major explanations for these attention failures with particular focus on the roles that brain immaturity and lack of driving experience play in causing attention problems. The review suggests that the potential for overcoming inexperience and immaturity with training to improve attention to both the driving task and hazards is substantial. Nevertheless, there are large individual differences in both attentional abilities and risky driving tendencies that pose challenges to novice driver policies. Research that can provide evidence-based direction for such policies is urgently needed.