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Verbal-Spatial Cue Conflict: Implications for the Design of Collision-Avoidance Warning Systems
Get PDFA spatial auditory Stroop paradigm was used to examine the effects of verbal-spatial cue conflict on response accuracy, reaction time, and driving performance. Participants responded to either the semantic meaning or the spatial location of a directional word, which were either congruent (i.e. the word “right” being presented from the right) or incongruent (i.e. the word “right” being presented from the left), while following a lead car in a simulated driving scenario. Accuracy was worse when participants were responding to the spatial location of a word in an incongruent trial, indicating that participants experienced significant interference when trying to ignore the semantic meaning of the word when it conflicted with the presentation location. Implications for the design of collision-avoidance warning systems are discussed
A Measure of Strong Driver Fatigue
Get PDFStrong fatigue during sustained operations is difficult to quantify because of its complex nature and large inter-individual differences. The most evident and unambiguous sign is the occurrence of microsleep (MS) events. We aimed at detecting MS utilizing computational intelligence methods. Our analysis was based on biosignal and video recordings of 10 healthy young adults who completed 14 sessions over two nights in our real-car driving simulation lab. Visual scoring by trained raters led to 2,290 examples of MS. Only evident events accompanied by prolonged eyelid closures, roving eye movements, head noddings, major driving incidents, and drift-out-of-lane accidents were regarded as MS. All other cases with signs of fatigue were regarded as dubious. The same amount of counterexamples (Non-MS) where continued driving was still possible were picked out from the recordings. Non-MS and MS examples covered only 15% of the whole time. Support-Vector Machines were utilized as classifiers and were adapted to these two classes of examples. If such classifiers were applied consecutively, then 100% of time is covered. Validation analysis demonstrated that the classifier gained high selectivity and high specificity. Based on this complete coverage, the percentage of MS in a predefined time span can be calculated. This measure was highly correlated to deteriorations in driving performance and to subjective self-ratings of sleepiness. We conclude that reliable detection of MS is possible despite large intra- and inter-individual differences in behaviour and in biosignal characteristics. Therefore, the percentage of detected MS gives an objective measure of strong driver fatigue
Collision Avoidance Training Using a Driving Simulator in Drivers with Parkinson's Disease: A Pilot Study
Get PDFParkinson’s disease (PD) impairs driving performance, and simulator studies have shown increased crashes compared to controls. In this pilot study, eight drivers with PD participated in three drive sessions with multiple simulator intersections of varying visibility and traffic load, where an incurring vehicle posed a crash risk. Over the course of the three sessions (once every 1-2 weeks), we observed reduction in crashes (p=0.059) and reaction times (p=0.006) to the vehicle incursion. These findings suggest that our simulator training program is feasible and potentially useful in drivers with PD. Future research questions include transfer of training to different driving tasks, duration of benefit, and the effect on long term real life outcomes in comparison to a standard intervention (e.g., driver education class) in a randomized trial
Ecodrive Training Delivers Substantial Fuel Savings for Heavy Vehicle Drivers
Get PDFA small group of heavy vehicle drivers underwent an ecodrive training course. Their driving was assessed for various ecodrive variables as they completed an 18 mile circuit in normal traffic immediately after the course and again 6 and 12 weeks later. Compared to pre-course measures, these drivers reduced their fuel consumption by an average of 27%, the number of gear changes by 29%, and the number of brake applications by 41%, though not all differences were statistically significant due to the size of this pilot and large driver variability. Importantly, the improvements were not offset by increases in the time taken to complete the circuit. At the 6 week point a control group was also assessed, and they used more fuel and more gear changes, and applied their brakes more often than the control group. Safety variables were inconclusive. A larger, in-service trial is warranted
Effects of Cell Phone Conversations on Driver Performance While Driving Under Highway Monotony
Get PDFIt has often been suggested by individuals that engaging in a cell phone conversation would help keep them awake under monotonous conditions where task underload might lead to a decrease in arousal. To further extend laboratory findings of performance in vigilance type tasks while distracted, a monotonous highway driving scenario was designed to test the anecdotal hypothesis of improved performance. Driver performance related to lane keeping and recall memory were studied under distracted and non-distracted conditions. Results of the simulator study were consistent with laboratory findings of performance decrement when dual tasking indicating that the perceived benefits from the secondary conversational task does not outweigh its costs
The Effect of Age on Decision Making During Unprotected Turns Across Oncoming Traffic
No full textThe present study examined whether age-related differences in quantitative measures of left-tum performance could explain older drivers' increased susceptibility to crashing while making unprotected left turns across traffic. Older and younger adults made left turns across traffic in a driving simulator. Time to decide to turn, time to negotiate the turn, the size of the accepted gap, gap clearance, and time to collision with an oncoming vehicle were measured. Significant effects of age were found in decision time, turn time and gap size. A significant interaction between age group and the speed of oncoming traffic was obtained for decision time. Implications for older adult's safety and future directions are discussed
Driver Comprehension of Integrated Collision Avoidance System Alerts Presented Through a Haptic Driver Seat
Get PDFThe purpose of this study was to quantify the effects of increasing the number of collision avoidance system alerts presented through a haptic driver seat on drivers’ response performance. Twenty-four participants performed specific driving maneuvers in response to one, three, or seven haptic seat alerts while they drove an instrumented vehicle. Participants verbally identified the alerts after executing a maneuver. Results show that drivers made the correct driving maneuver in response to the alerts. This was likely because of the strong stimulusresponse compatibility designed into the haptic seat. As predicted by Information Theory, drivers’ mean manual response time to the alerts significantly increased, and their verbal response accuracy significantly degraded, as the number of alerts increased. A three-alert haptic seat approach is recommended providing specific design requirements are met
Estimating Fatigue from Predetermined Speech Samples Transmitted by Operator Communication Systems
Get PDFWe present an estimation of fatigue level within individual operators using voice analysis. One advantage of voice analysis is its utilization of already existing operator communications hardware (2-way radio). From the driver viewpoint it’s an unobtrusive, non-interfering, secondary task. The expected fatigue induced speech changes refer to the voice categories of intensity, rhythm, pause patterns, intonation, speech rate, articulation, and speech quality. Due to inter-individual differences in speech pattern we recorded speaker dependent baselines under alert conditions. Furthermore, sophisticated classification tools (e.g. Support Vector Machine, Multi-Layer Perceptron) were applied to distinguish these different fatigue clusters. To validate the voice analysis predetermined speech samples gained from a driving simulator based sleep deprivation study (N=12; 01.00-08.00 a.m.) are used. Using standard acoustic feature computation procedures we selected 1748 features and fed them into 8 machine learning methods. After each combining the output of each single classifier we yielded a recognition rate of 83.8% in classifying slight from strong fatigue
Nighttime Speed Negotiation on Rural Road S-Shaped Curves: Discussion of an Experimental Case-Study
Get PDFRoad users’ perception of risk while driving is the focal point discriminating prudent from imprudent behavior. One of the main factors that can influence a driver’s level of risk perception is ‘lighting’, given that the driving conditions on roads alter radically between daytime and nighttime hours. This paper describes the results of a study conducted along a section of rural road containing a sharp S-shaped curve linking two long rectilinear approach roads in the sequence ‘tangent-curve-tangent’. The driving behavior of the road users was surveyed in both directions of travel by day and at night, demonstrating a notable discrepancy in driving style between the two conditions
Useful Field of View Impairments in Drivers with Obstructive Sleep Apnea
Get PDFAs a group, drivers with obstructive sleep apnea (OSA) have an increased risk for motor vehicle crashes, but determining individual crash risk is difficult. We tested the hypothesis that drivers with OSA have impaired visual attention, as indexed by reduced useful field of view (UFOV), a predictor of highrisk driving. Forty-one drivers with untreated OSA and 50 comparison drivers were assessed by UFOV. OSA drivers performed significantly worse than controls on all UFOV subtests and had reduced UFOV as indicated by a higher mean total UFOV score (p = 0.0017). However, only 4 OSA and 2 control drivers had values indicative of high crash risk (UFOV reduction >23%). Drivers with OSA have reduced UFOV compared to drivers without neurological or sleep disorders. However, as UFOV identifies few high-risk drivers, its role in assessing crash risk in an unselected population of drivers with OSA appears to be limited