Suzanne E. Lee

Distracted Driving and Risk of Road Crashes among Novice and Experienced Drivers

BACKGROUND Distracted driving attributable to the performance of secondary tasks is a major cause of motor vehicle crashes both among teenagers who are novice drivers and among adults who are experienced drivers. METHODS We conducted two studies on the relationship between the performance of secondary tasks, including cell-phone use, and the risk of crashes and near-crashes. To facilitate objective assessment, accelerometers, cameras, global positioning systems, and other sensors were installed in the vehicles of 42 newly licensed drivers (16.3 to 17.0 years of age) and 109 adults with more driving experience. RESULTS During the study periods, 167 crashes and near-crashes among novice drivers and 518 crashes and near-crashes among experienced drivers were identified. The risk of a crash or near-crash among novice drivers increased significantly if they were dialing a cell phone (odds ratio, 8.32; 95% confidence interval [CI], 2.83 to 24.42), reaching for a cell phone (odds ratio, 7.05; 95% CI, 2.64 to 18.83), sending or receiving text messages (odds ratio, 3.87; 95% CI, 1.62 to 9.25), reaching for an object other than a cell phone (odds ratio, 8.00; 95% CI, 3.67 to 17.50), looking at a roadside object (odds ratio, 3.90; 95% CI, 1.72 to 8.81), or eating (odds ratio, 2.99; 95% CI, 1.30 to 6.91). Among experienced drivers, dialing a cell phone was associated with a significantly increased risk of a crash or near-crash (odds ratio, 2.49; 95% CI, 1.38 to 4.54); the risk associated with texting or accessing the Internet was not assessed in this population. The prevalence of high-risk attention to secondary tasks increased over time among novice drivers but not among experienced drivers. CONCLUSIONS The risk of a crash or near-crash among novice drivers increased with the performance of many secondary tasks, including texting and dialing cell phones. (Funded by the Eunice Kennedy Shriver National Institute of Child Health and Human Development and the National Highway Traffic Safety Administration.).

DETECTION OF ROAD HAZARDS BY NOVICE TEEN AND EXPERIENCED ADULT DRIVERS.

Previous laboratory and simulator research has indicated that hazard detection skills and abilities are less developed among novice drivers compared with experienced adult drivers. Novices tend to miss some relevant cues and may be less able to process important elements in the environment while driving. It was hypothesized that novices would have lower hazard detection skills and would react less appropriately to hazards than older and more experienced drivers. Three hazard perception scenarios were simulated on a test track, and data were collected on newly licensed teen drivers (within 2 weeks of licensure) and a comparison group of adults. The scenarios included a hidden stop sign, hidden pedestrian, and hidden pedestrian with lane closure (this last included a text-messaging task). Discrete quantitative performance metrics were evaluated for this analysis, including the following: (a) Did the participant glance at the potential hazard (e.g., stop sign, pedestrian)? (b) Did the participant stop (for the stop sign scenario)? (c) Did the participant show signs of indecision, caution, or awareness (for all hazards)? Significant differences between teen drivers and more experienced adult drivers were found in a combined hazard detection analysis. Results indicated that the adult drivers observed hazards and demonstrated overt recognition of hazards more frequently than the teen drivers did. Results indicated that a large portion of teen drivers failed to disengage from peripheral task engagement in the presence of hazards. The results will be compared with naturalistic data for the same set of drivers to see whether these test track results are predictive of real-world behavior.

Eyeglance Behavior of Novice Teen and Experienced Adult Drivers

Eyeglance behavior and scanning patterns may be learned as a driver gains experience and lead to greater situation awareness on the part of the driver. This may help to explain differences observed in the safety records of novice teen and experienced adult drivers. For example, new drivers may focus almost exclusively on the road ahead and spend little time scanning the vehicles mirrors. However, a novice driver performing a secondary task may spend more time with his or her eyes on the task than on the road, because of unfamiliarity with the vehicle or inexperience with consequences of long glances away from the forward view. For this study, 18 novice teen (under 17.5 years old and within 4 weeks of licensure) and 18 experienced adult drivers performed a set of in-vehicle tasks on a test track. A baseline driving segment was also included. Measures consisted of percentage of eyes-off-road (EOR) time, number of glances, and mean single-glance time. Results showed that teens glanced at the rearview mirror...

Analysis of Distribution, Frequency, and Duration of Naturalistic Lane Changes

This paper describes preliminary results of naturalistic lane change distribution, frequency, and duration data collected unobtrusively from 16 commuters using instrumented vehicles. The study was designed to improve upon previous data collection methods and support crash avoidance system development. A total of 8,667 lane changes (including unsuccessful maneuvers) were identified and classified in terms of severity, urgency, maneuver type, and success/magnitude. The total miles driven was 23,949 (38,542 km) with an average of 37.4 miles (60.2 km) per commute and 2.76 miles (4.44 km) per lane change. More than 37% of lane changes were due to a slow vehicle ahead. The mean duration for 7,192 single lane changes was 6.28 seconds with a standard deviation of 2.0. Analysis revealed no significant effects for duration. For frequency, significantly more lane changes were completed by drivers on the interstate, perhaps due to traffic density, while sedan drivers made significantly more lane changes than SUV drivers. A significant driver type (vehicle normally driven) by route (interstate or highway) interaction was discovered, perhaps due to driving style. A gender by route interaction was also found.

Investigation of Driver-Infrastructure and Driver-Vehicle Interfaces for an Intersection Violation Warning System

Research was undertaken to design, develop, and evaluate interfaces for a signalized- and stop-controlled violation warning system. Both infrastructure-based warnings (Driver Infrastructure Interface, DII) and vehicle-based warnings (Driver Vehicle Interface, DVI) were considered. The developed interfaces were tested by placing a driver in an instrumented vehicle on a closed test course with a working signalized intersection. The goal of the effort was to determine which DIIs/DVIs were most effective based upon the time to intersection at which the DII/DVI elicited the correct driver response of braking by the stop bar. While the DIIs that were tested were shown to be largely ineffective for violation warning, results showcase the potential of several DVI modalities, by themselves or in combination, to provide effective warnings to a driver violating a signal- or stop-controlled intersection. Furthermore, results indicate that a DVI warning combined with a vehicles enhanced braking capability (brake precharging and panic brake assist) may enhance the range of acceptable DVIs.

Naturalistic Teenage Driving Study: Findings and Lessons Learned

INTRODUCTION This paper summarizes the findings on novice teenage driving outcomes (e.g., crashes and risky driving behaviors) from the Naturalistic Teenage Driving Study. METHOD Survey and driving data from a data acquisition system (global positioning system, accelerometers, cameras) were collected from 42 newly licensed teenage drivers and their parents during the first 18 months of teenage licensure; stress responsivity was also measured in teenagers. RESULT Overall teenage crash and near-crash (CNC) rates declined over time, but were >4 times higher among teenagers than adults. Contributing factors to teenage CNC rates included secondary task engagement (e.g., distraction), kinematic risky driving, low stress responsivity, and risky social norms. CONCLUSIONS The data support the contention that the high novice teenage CNC risk is due both to inexperience and risky driving behavior, particularly kinematic risky driving and secondary task engagement. PRACTICAL APPLICATIONS Graduated driver licensing policy and other prevention efforts should focus on kinematic risky driving, secondary task engagement, and risky social norms.

Variability in Crash and Near-Crash Risk among Novice Teenage Drivers: A Naturalistic Study

OBJECTIVE Using video monitoring technologies, we investigated teenage driving risk variation during the first 18 months of independent driving. STUDY DESIGN Driving data were collected on 42 teenagers whose vehicles were instrumented with sophisticated video and data recording devices. Surveys on demographic and personality characteristics were administered at baseline. Drivers were classified into 3 risk groups using a K-mean clustering method based on crash and near-crash (CNC) rate. The change in CNC rates over time was evaluated by mixed-effect Poisson models. RESULTS Compared with the first 3 months after licensure (first quarter), the CNC rate for participants during the third, fourth, and fifth quarters decreased significantly to 59%, 62%, and 48%, respectively. Three distinct risk groups were identified with CNC rates of 21.8 (high-risk), 8.3 (moderate-risk), and 2.1 (low-risk) per 10 000 km traveled. High- and low-risk drivers showed no significant change in CNC rates throughout the 18-month study period. CNC rates for moderate-risk drivers decreased substantially from 8.8 per 10 000 km in the first quarter to 0.8 and 3.2 in the fourth and fifth quarters, respectively. The 3 groups were not distinguishable with respect to personality characteristics. CONCLUSION Teenage CNC rates varied substantially, with distinct high-, moderate-, and low-risk groups. Risk declined over time only in the moderate-risk group. The high-risk drivers appeared to be insensitive to experience, with CNC rates consistently high throughout the 18-month study period, and the moderate-risk group appeared to learn from experience.

The effects of age on crash risk associated with driver distraction

Background Driver distraction is a major contributing factor to crashes, which are the leading cause of death for the US population under 35 years of age. The prevalence of secondary-task engagement and its impacts on distraction and crashes may vary substantially by driver age. Methods Driving performance and behaviour data were collected continuously using multiple cameras and sensors in situ for 3542 participant drivers recruited for up to 3 years for the Second Strategic Highway Research Program Naturalistic Driving Study. Secondary-task engagement at the onset of crashes and during normal driving segments was identified from videos. A case-cohort approach was used to estimate the crash odds ratios associated with, and the prevalence of, secondary tasks for four age groups: 16-20, 21-29, 30-64 and 65-98 years of age. Only severe crashes (property damage and higher severity) were included in the analysis. Results Secondary-task-induced distraction posed a consistently higher threat for drivers younger than 30 and above 65 when compared with middle-aged drivers, although senior drivers engaged in secondary tasks much less frequently than their younger counterparts. Secondary tasks with high visual-manual demand (e.g. visual-manual tasks performed on cell phones) affected drivers of all ages. Certain secondary tasks, such as operation of in-vehicle devices and talking/singing, increased the risk for only certain age groups. Conclusions Teenaged, young adult drivers and senior drivers are more adversely impacted by secondary-task engagement than middle-aged drivers. Visual-manual distractions impact drivers of all ages, whereas cognitive distraction may have a larger impact on young drivers.

Naturalistic Driving Study: Technical Coordination and Quality Control

This report describes the technical coordination and quality control carried out by the Virginia Tech Transportation Institute (VTTI) for the Strategic Highway Research Program 2 (SHRP 2) Naturalistic Driving Study (NDS). This project encompassed procurement of the data acquisition system (DAS) and all associated installation and driver assessment equipment; coordination of human subjects protections; participant recruitment; training and coordination of the six site contractors that carried out participant enrollment, instrumentation, and data retrieval; data management; data processing; and quality control. From October 2010 through November 2013, the study collected continuous driving information on more than 3,000 light-vehicle drivers, covering about 50 million miles of driving in the six study sites. In this report, potential users of the SHRP 2 NDS data or findings will find a summary of data collection methods and procedures, instrumentation, quality control, and project management.

Test Road Experiment on Imminent Warning Rear Lighting and Signaling

Objective: This paper describes an experiment directed toward refinement and initial field testing of two potential countermeasures for the problem of rear-end (RE) crashes. The countermeasures consist of “imminent warning” signals intended to direct the following drivers visual glance to the lead vehicle as it brakes rapidly to a stop and for a short time thereafter. Background: RE crashes are the most frequently occurring type of light vehicle crash, making up at least 25% of all crashes. Method: A preliminary experiment was conducted to facilitate improvement of the attention-getting capability of an alternating pair of lamps. In the main experiment, an oscillating narrow beam lamp (a promising candidate from a previous experiment) and an improved alternating pair (improved as compared with that in a previous experiment) were compared with ordinary rear lighting. Seventy-two drivers were purposely distracted by in-vehicle tasks as the lead (surrogate) vehicle braked hard. Results: Results showed improvements of 0.25 to 0.35 s in brake activation times for the two enhanced configurations as compared with ordinary rear lighting. Conclusion: The two enhanced lighting configurations show promise in reducing the number and severity of RE crashes. Application: The methods and results of this study can be applied to the future design and evaluation of automotive rear-end lighting designed to reduce RE crashes.