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Identifying Fatality Factors of Rural and Urban Safety Cultures
Get PDFThe fatality rate in rural areas is considerably higher than it is in urban areas. In order to better understand the differences and similarities between attitudes and behaviors of drivers in different geographic areas, a large scale survey was conducted in both rural and urban counties within the state of Minnesota. As part of this survey, recipients were asked to rate the frequency and dangerousness of risk factors that play a role in fatal crashes. They were also asked to rate how effective and desirable a number of proposed safety interventions would be in their own communities. Though both urban and rural drivers reported practicing various unsafe driving behaviors, rural drivers engaged in particular factors, such as not wearing a safety belt, and did not recognize the true extent of these risks. Rural drivers also consistently felt that proposed safety interventions were less useful than did drivers from urban areas. It is hoped these results can be used to help instruct research efforts and inform policy decisions of the attitudes and beliefs of drivers who experience differing safety cultures
Near Peripheral Motion Detection Threshold Predicts Detection Failure Accident Risk in Younger and Older Drivers
No full textMotion contrast thresholds for 0.4 cycle/degree drifting Gabor stimuli were assessed at 15-degrees eccentricity for 16 younger drivers (ages 24 to 42), and 15 older drivers (ages 65 to 84), using a temporal two-alternative forced choice staircase procedure. Two self-report questionnaires assessed detection failure accident risk—the Driver Perception Questionnaire (DPQ5), and an abridged Aging Driver Questionnaire (ADQ15). The UFOV® test battery was also administered. Mean peripheral motion contrast thresholds (PMCT) of younger and older participants were –39.3 dB and –33.8 dB, respectively. For younger drivers, the correlation between PMCT and DPQ5 scores was .62 (p<.01), and between DPQ5 and ADQ16 (new and validated self-report measures, respectively) was .59 (p<.01). For older drivers, correlation between PMCT and DPQ5 scores was .49 (p<.01), between DPQ5 and ADQ16 was .73 (p<.01), and between PMCT and age was .49 (p<.05). For drivers overall, correlation was .48 (p<.01) between PMCT and DPQ5 scores, .63 (p<.0001) between DPQ5 and ADQ16, and .69 (p<.0001) between PMCT and age. For drivers overall, correlation was .30 (p<.05) between UFOV1 and age, .67 (p<.0001) between UFOV2 and age, .56 (p<.001) between UFOV2 and PMCT, .80 (p<.0001) between UFOV3 and age, and .58 (p<.001) between UFOV3 and PMCT. Holding age constant, partial correlation of PMCT with DPQ5 was .55 (p<.001), and of PMCT with ADQ15 was .39 (p<.05). PMCT significantly predicted self-reported driving performance in a laboratory setting, and worsened significantly with age. PMCT assessment should be made practicable. Informing high-risk drivers may encourage appropriate risk reduction countermeasures
Objective Methods for Assessments of Influence of IVIS (In-Vehicle Information Systems) on Safe Driving
Get PDFThe main objective of experiments focused on assessments of in-car devices (IVIS in this case) is to evaluate objectively their influence on safety and comfort of driving. This paper presents a big set of experiments performed on our driving simulators. Besides the experiment setup, it describes several different methods used for the classification of driver behavior based either on analysis of technical outputs from simulated driving or subjective and psycho-physiological measures. The aim of the whole project is to find out the objective methodology (a complex set of methods) for assessment of IVIS (or further any HMI devices used in the cars) with respect to drivers’ skills and personalities
Shouldn’t Cars React as Drivers Expect?
No full textThe objective of this project is to develop and test a multi-method empirical approach for predicting drivers’ assessments of the level of acceptability of a warning issued in response to accidents, near-accidents, and other incidents. The role of humans (drivers) in the pre-crash phase means that systems that protect occupants and pedestrians must be seen as distributed, cognitive systems. Driver acceptance therefore has to be an important design goal. One obstacle to acceptance is the human dislike for false alarms. An approach to overcoming driver dislike for false alarms is to focus on driver expectations and to design systems to issue alarms when and only when the driver is likely to accept them. In this paper we discuss one such approach
Vision in Night Driving: The Roles of Rod and Cone Photoreceptors
Get PDFBecause of the low light levels that are important in night driving, it is possible that both rods and cones contribute to visual performance for drivers at night. However, little evidence has been available about the relative contributions of these classes of photoreceptors. Partly, this may be because until recently the range of light sources has been limited, and consequently the question was not of great practical importance, at least for photometry. However, there is now a much larger variety of sources in use for vehicle lighting, including high-intensity discharge (HID) and light emitting diode (LED) sources. The greater variety of sources and spectral power distributions has increased interest in how the visual response of a driver’s eyes at night varies with wavelength. New evidence indicates that the relative contributions of rods and cones may be different for different driving tasks or different aspects of a driver’s visual experience at night: detection of pedestrians—the task that is most critically affected by darkness— may depend primarily on cones, while subjective impressions of brightness, and perhaps the conspicuity of emergency signals in the visual periphery, may be strongly influenced by rods
An Examination of the Relationship Between Attention Profiles and Simulated Driving Performance
Get PDFThis study examined whether attention profiles from a computerized test battery relate to simulated driving performance. Five attention abilities were examined in the study: sustained, divided, selective, switching, and scanning. Participants completed eight tasks in a computer-based test battery and four driving scenarios designed to tap the same attention abilities. Physiological measures were collected during the test battery and the driving scenarios. Principal components analysis (PCA) with varimax rotation extracted seven components from the test battery, including the five proposed abilities along with speed and orienting components. Component scores were used as predictors of simulated driving performance in stepwise regressions and explained a significant proportion of variance (ranging from 7% - 26%) for most measures of driving performance. The speed, visual search, and divided attention components appeared as significant predictors more often than did the sustained, switching, orienting, and selective components. When physiological measures were added to the regressions, they explained additional variance beyond that explained by the component scores, but there was no consistent relation between simulated driving performance and any particular physiological measure
Comparison of Driver Brake Reaction Times to Multimodal Rear-end Collision Warnings
No full textThis study examined the effectiveness of rear-end collision warnings presented in different sensory modalities as a function of warning timing in a driving simulator. Drivers experienced four warning conditions: no warning, visual, auditory, and tactile. The warnings activated when the time-to-collision (TTC) reached a critical value of 3.0 or 5.0 s TTC. Driver reaction time (RT) was captured from the time the driver crossed the warning activation threshold to brake initiation. Mean driver RT data showed that the tactile warning significantly outperformed the visual warning, providing support for tactile displays as effective rear-end collision warnings
Field Test Results of a Road Departure Crash Warning System: Driver Utilization and Safety Implications
Get PDFThe Road Departure Crash Warning System Field Operational Test (RDCW FOT) was conducted to assess the safety impacts, driver acceptance levels, and the maturity of road departure crash warning systems as installed on a light vehicle platform. This paper presents the experimental design, performance of the road departure system in naturalistic use, and analyses of safety impacts of the technology using surrogate measures. Use of the system led to a 50% reduction in the observed rate of events in which the equipped vehicle came within 0.1 m of a lane edge in steady-state lane-keeping situations. Lane changes performed without the use of a turn signal were reduced by 43% on freeways and ramps and 24% on surface roads. Levels of lateral acceleration in curves was not significantly different, except on ramps, where a significant change in the 90th percentile values of lateral acceleration were observed for a within-subject comparison. There were no observed effects of risk homeostasis and no evidence of significant negative unintended consequences
The Effects Of Sleep Apnea on Heart Rate Variability in a Simulator
Get PDFHeart rate variability has been used as a measure of mental workload, stress, and fatigue in drivers. The main goal of this study was to evaluate whether drivers with obstructive sleep apnea syndrome (OSAS) may have significantly different heart rate variability from those who do not have OSAS. Such a condition may indicate lower stress levels and an increase in crash risk due to sleepiness. This study also evaluates whether significant deviations in HRV may occur as drivers become drowsier over time. Eleven drivers with OSAS were compared to twelve other drivers with no known sleep disorder. All were tested in a driving simulator over a 60-minute period that consisted of three uneventful drive segments on two-lane rural roads. Heart rates were collected using electrocardiogram (ECG). The variability of heart rate was computed for each subsequent five-minute interval by calculating the standard deviations of the R-R intervals (i.e., the time duration between two consecutive R waves of the ECG) within that time. Results showed that there were no significant differences in HRV over time for the comparison group. However, HRV for drivers with OSAS increased by each subsequent time interval. Drivers with OSAS also had significantly higher mean heart rate variability over the course of the drive. Specifically, based on the second regression model, the difference in heart rate variability between drivers with OSAS and the comparison group significantly increased after about 25 minutes of driving. This likely reflects the physiological effects of increased fatigue, which would lead to inattention to the driving environment and increased crash risk
Why Driving Performance Measures Are Sometimes Not Accurate (and Methods to Check Accuracy)
No full textThis paper identifies common sources of inconsistency and error in measurements of driving performance and describes methods to determine the size of these errors. Major sources of inconsistency and error discussed include (1) the lack of zeroing procedures (which affects measurements of steering wheel angle), (2) unknown input and output mapping (which affects measurements of throttle position), (3) the failure to control critical factors such as tire pressure, traffic, and wind (which affects measurements of speed), (4) uncertainty about where the lane boundary actually is (which affect measurements of lane position and counts of lane departures), and (5) the failure to define or use consistent definitions for measures such as headway/gap, time to line crossing, and time to collision. The lack of or inconsistency of definitions can lead to multiple interpretations of what could have been measured, and differences between interpretations are of practical significance. The types and magnitude of these inconsistencies and errors vary with the measurement platform, complicating the comparison of driving studies and interfering with building a body of knowledge of driving. By making the driving research community aware of these problems, they can be identified, assessed, and minimized in the future, and published research can be read with a more critical eye