729 research outputs found
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Human Factors Issues Associated with Limited Ability Autonomous Driving Systems: Drivers’ Allocation of Visual Attention to the Forward Roadway
No full textThis study characterized driver behavior and established a foundation for defining functional performance requirements associated with a Limited Ability Autonomous Driving System (LAADS) – a system capable of automated steering and speed/headway maintenance tasks on freeways, but does not relieve drivers of all driving tasks. The research was designed to examine and reveal potential issues associated with the use of semi-autonomous systems, exploring impacts on willingness to engage in secondary non-driving related tasks, and driver allocation of visual attention while operating under LAADS (ACC and Lane Centering). Results found meaningful differences in the allocation of visual attention across ACC and LAADS driving under situations where drivers were engaged in a secondary task. Overall findings suggest that given a rudimentary, but reliable, LAADS system (one which does not monitor or otherwise restrict behavior) drivers are likely to increase the frequency of secondary task interactions, and engage in risky tasks that are likely to increase extended glances away from the forward roadway
Validity of the C-RDS Self-Reported Risky Driving Measure
No full textThis study examined the reliability and validity of the Checkpoints Risky Driving Scale (C-RDS) in relation to the Dula Dangerous Driving Index (DDDI) and an objective measure of risky driving. Naturalistic and survey data were collected over an 18-month period from 42 newly-licensed teenage drivers. Kinematic Risky Driving was operationally defined as the rate of elevated gravitational-force events per 100 miles obtained from accelerometers and global positioning systems. Two self-report measures of risky driving, the C-RDS and the DDDI, were assessed at 6-months, 12-months, and 18-months after licensure. Reliability was examined for each measure with correlations and autoregressive models over three time points. Validity was assessed by correlations between the measures and cross-lagged autoregressive models of the longitudinal association of self-reported measures with Kinematic Risky Driving and vice versa. Both the C-RDS and DDDI measures demonstrated substantial stability over time and were highly correlated with each other. The C-RDS measure was significantly associated with Kinematic Risky Driving. The findings provide evidence for the reliability and validity of C-RDS
3D Spatial Attention Effects are Independent of Projected 2D Size and Location for Older and Younger Drivers
No full textPrevious research has found the reaction time (RT) to light change targets when performing a car following task, is partially dependent on the distance in depth of the target from the driver. Researchers have concluded from this evidence that the spatial extent of attention is three dimensional (3D) during dual-task driving. However, in prior experiments the effect of two-dimensional (2D) projected size and position was not experimentally controlled. If spatial attention is 3D, then there should be an effect of target distance when 2D projected size and position are constant. The purpose of the current work was to assess this hypothesis. We manipulated the size and position of light-change targets at different depths to hold the projected size and position of targets constant between blocks. Although projected size and position were identical in this experiment, the results demonstrated that for younger and older drivers, targets further from the driver were responded to more slowly than targets closer to the driver. These results demonstrate that 3D attention effects are not dependent on projected size or position, and that the mechanism of 3D attention is present in younger and older drivers. These results, considered with the findings of other studies, suggest that tests to assess crash risk, such as the UFOV, are limited in scope because such tests fail to incorporate variation in attention as a function of distance
Naturalistic Studies of Driver Distraction: Effects of Analysis Methods on Odds Ratios and Population Attributable Risk
No full textWhen analyzing naturalistic driver performance data, different analysis methods can have large impacts on safety estimates for the condition being assessed. To illustrate, this paper reanalyzed the data for a secondary task (conversation on a hand-held cell phone) from the recently-released Virginia Tech Transportation Institute (VTTI) 100-Car databases, using a standard method for epidemiological analysis. It found substantially lower estimates for the odds ratio (OR), population exposure percent (Pe%), and population attributable risk percent (PAR%) than with the VTTI analysis method. The crash/near-crash OR was reported by VTTI as 1.29, but was found to be 0.78 with the standard method, a reversal in direction from a potentially crash-increasing to a potentially crash-reducing effect. The Pe% for crashes/near-crashes was 12.5% using the VTTI method, but declined to 6.7% with the standard method. The PAR% was reported as 3.6% but a population preventive fraction of 1.5% (a protective effect) was estimated by the standard method. The OR difference was traced to an “assumption bias” in the VTTI method that had unequal effects for the unexposed vs. exposed cases. The Pe% and PAR% differences were traced to an error in the VTTI calculation of Pe%. This bias and error were systemic in the VTTI analysis methods, overestimating OR, Pe%, and PAR% for all tasks examined. Future research should seek to better understand the epidemiologic analysis methods that are most appropriate in the new and emerging field of naturalistic driving research
Permissive Left-Turn Behavior at the Flashing Yellow Arrow in the Presence of Pedestrians
No full textUse of the flashing yellow arrow indication for permissive left-turn control has become more common in the U.S. since it was adopted in the 2009 Edition of the Manual on Uniform Traffic Control Devices. A complete understanding of the safety implications at signalized intersections is critically important. This paper examines the results of a permissive left-turn driver behavior study conducted in a high fidelity driving simulator. The experimental results suggest 1) that when there are more pedestrians present in the conflicting crosswalk, the driver’s average fixation duration on crossing pedestrians is greater than when there is minimal pedestrian activity; 2) that 4% to 7% of drivers do not fixate on pedestrians in the crosswalk when completing their left turn; and 3) that 39% of drivers do not fixate on likely pedestrian locations when pedestrians are not present
Comparison of Static and Driving Simulator Venues for the Tactile Detection Response Task
No full textThe general objective of the present study was to validate a low-cost, static, version of the Tactile Detection Response Task (TDRT) intended for driver-vehicle interface evaluation in industrial settings. The static TDRT venue was compared to the more commonly used driving simulator venue, where the TDRT and the secondary task under evaluation are performed during simulated driving. The results indicated that the effect of venue was additive over a range of visual-manual and cognitive secondary tasks, which offers preliminary support for the static TDRT venue as a surrogate for the driving simulator TDRT venue. However, a more detailed analysis revealed a counterintuitive effect for one of the visual-manual secondary tasks (SuRT), where the easier version of the task (as confirmed by subjective workload ratings) yielded a stronger effect on the TDRT than the more difficult version. Possible explanations and implications for the TDRT and its application to driver-vehicle interface evaluation are discussed
The Long Road Home: Driving Performance and Ocular Measurements of Drowsiness Following Night Shift-Work
No full textBecause time-of-day effects on sleepiness interact with duration of prior waking, the commute home following a night shift is an especially vulnerable time for night shift workers. The current study aimed to explore the impact of night shift work on critical driving events as well as to explore physiological indices leading up to these events. Sixteen healthy night shift workers (18-65 years) each participated in two 2-hour driving sessions in an instrumented vehicle on a driving track. A baseline driving session was conducted following a night of rest, while another session was conducted following a night of shift work. Objective physiological measurements of drowsiness were monitored and collected continuously throughout the drive session as well as different measures of driving performance. Following the night-shift, drivers had higher Johns Drowsiness Scores (based on ocular measures) and were more likely to experience lane excursion events and investigator-initiated braking events than following a night’s rest. While they also reported increasing failures in lane keeping ability, the pattern was not always consistent with actual observed data. The implications for countermeasures are discussed
Comparison of the Minisim and Stisim Driving Simulators for the Detection of Impairment: An Alcohol Validation Study
No full textDetection of alcohol impairment is often used to evaluate the sensitivity of a protocol to detect the effects of other types of impairment. This study was designed to compare the sensitivity of two simulator platforms with different underlying architectures using equivalent driving scenarios. The driving scenario consisted of a twenty minute drive on a relatively straight rural roadway with a divided attention task presented infrequently during the drive. A total of 18 subjects completed drives on both simulators at two levels of BAC. It was hypothesized that both simulator platforms would be sensitive to the effects of alcohol. On driving variables and on divided attention variables the MiniSim simulator showed greater sensitivity to the impairing effects of alcohol (at doses below 0.10% BAC) than was found with the STI simulator. The SDLP variable (lane position deviation) was sensitive to alcohol effects with both simulators. However, there was clearly greater sensitivity seen with the MiniSim simulator. For a number of driving and divided attention variables significant results were obtained with the MiniSim, whereas results for the STISIM failed to show a significant alcohol effect. The greater sensitivity of the MiniSim compared to the STISIM is potentially due to a number of differences between the two simulators, though the difference in the vehicle dynamics model would be expected to be the largest determining factor
Not So Fast! An Investigation of Real-World Speeding Behaviors and Underlying Attitudes
No full textAlthough speeding is a major contributor to traffic fatalities, attempts to address this problem have not led to significant reductions in speed-related crashes. In this paper, we describe an investigation of speeding behaviors that was intended to: (1) identify which drivers speed, (2) model the relative roles of situational, demographic, and personality factors in predicting travel speeds, and (3) classify drivers based on their speeding patterns. The speeding behaviors of 88 drivers were recorded over the course of approximately four weeks of naturalistic driving in Seattle WA. Data collected included 1-Hz recordings of vehicle position and speed using a GPS receiver, and responses to survey questions. Regression models were developed to identify predictors of 1) “any” speeding and 2) amount of speeding. Significant predictors included demographic variables such as age and gender, situational factors such as time-of-day and day-of-week, and key personality factors such as attitudes towards reckless driving
Novice Teenage Driver Cell Phone Use Prevalence
No full textNovice teenage drivers have high crash rates due to inexperience; therefore, cell phone-related secondary task engagement (distracted driving) is likely to aggravate crash risk for this population. A previous study of teenage distracted driving behavior, found that 34% of 16-17- year-olds had texted, and 52% reported talking on a cell phone while driving (Madden & Lenhart, 2009). In the current study, data from the NEXT Generation Health Study were analyzed to estimate the prevalence of cell phone-related distracted driving in a nationally representative sample of U.S. eleventh grade students, the age when most teenagers are first eligible to receive a license to drive independently. Using the subsample of teenagers that reported having a license that allowed independent, driving (n = 881), the prevalence of cell phone-related distracted driving was estimated. Nationwide, four out of five (80.0%) teenage drivers reported making or receiving a call, and 72.0% reported sending or receiving a text message at least one day in the past 30 days. In addition, teenagers reported talking on 32.6% and texting on 40.3% of the days they drove. Access to a vehicle, the number of miles teenagers drove each day (the more driving the more phone use), and race/ethnicity (Asians had lower cell phone use than Whites, Hispanics, or African-Americans), were significantly associated with cell phone-related distracted driving. These findings indicate a higher prevalence of teenage cell phone use while driving than previous studies. More research is needed to understand predictors, safety outcomes, and prevention approaches for teenage distracted driving