Adi Ronen

Alertness maintaining tasks (AMTs) while driving

We evaluated the effectiveness of alertness maintaining tasks (AMTs) on driver performance, subjective feelings, and psychophysiological state in monotonous simulated driving in two experiments. In the first experiment, 12 professional truck drivers participated in five sessions of simulated driving: driving only, driving with one of three AMTs (counterbalanced), and driving while listening to music. AMTs were not equally effective in maintaining alertness. The trivia AMT prevented driving performance deterioration, and increased alertness (measured by standardized HRV). The choice reaction time AMT was least demanding but also increased subjective sleepiness and reduced arousal (measured by alpha/beta ratio). The working memory AMT caused a significant decrement in driving speed, increased subjective fatigue, and was regarded by the participants as detrimental to driving. Trivia was preferred by the majority of the drivers over the other two AMTs. Experiment 2 further examined the utility of the trivia AMT. When the drivers engaged in the trivia AMT they maintained better driving performance and perceived the driving duration as shorter than the control condition. The two experiments demonstrated that AMTs can have a positive effect on alertness. The effect is localized in the sense that it does not persist beyond the period of the AMT activation.

Effects of THC on driving performance, physiological state and subjective feelings relative to alcohol

BACKGROUND The effects of marijuana or THC on driving has been tested in several studies, but usually not in conjunction with physiological and subjective responses and not in comparison to alcohol effects on all three types of measures. OBJECTIVE To assess the effects of two dosages of THC relative to alcohol on driving performance, physiological strain, and subjective feelings. METHOD We tested the subjective feelings and driving abilities after placebo, smoking two dosages of THC (13 mg and 17 mg), drinking (0.05% BAC) and 24 h after smoking the high dose THC cigarette, while monitoring physiological activity of the drugs by heart rate. Fourteen healthy students, all recreational marijuana users, participated in the study. RESULTS Both levels of THC cigarettes significantly affected the subjects in a dose-dependent manner. The moderate dose of alcohol and the low THC dose were equally detrimental to some of the driving abilities, with some differences between the two drugs. THC primarily caused elevation in physical effort and physical discomfort during the drive while alcohol tended to affect sleepiness level. After THC administration, subjects drove significantly slower than in the control condition, while after alcohol ingestion, subjects drove significantly faster than in the control condition. No THC effects were observed after 24 h on any of the measures.

Usage and perceived effectiveness of fatigue countermeasures for professional and nonprofessional drivers

BACKGROUND Drivers adopt various strategies in order to cope with fatigue and falling asleep at the wheel. These strategies include a wide range of activities that may invigorate the body and/or the mind. OBJECTIVES To compare usage patterns and to evaluate the perceived effectiveness of different coping behaviors adopted by professional and nonprofessional drivers in order to maintain alertness. METHOD The study was conducted using a large-scale survey, filled by 100 professional and 90 nonprofessional drivers. RESULTS Listening to the radio and opening the window were the most frequently used and also perceived as highly effective coping behaviors by both groups of drivers. Talking on a cellular phone or with a passenger were more frequently used by nonprofessional drivers whereas, planning rest stops ahead, stopping for a short nap and drinking coffee were more frequently used by professional drivers. These methods were also perceived as more effective by professional than by the nonprofessional drivers and their usage frequency highly correlated with their perceived effectiveness. CONCLUSIONS Nonprofessional drivers counteract fatigue only at the tactical/maneuvering level of the drive. Hence, they tend to adopt methods that help them pass the time and reduce their feeling of boredom but do not require advance preparations or adjustments in the driving. In contrast, professional drivers counteract fatigue also at the strategic/planning level of driving, and use a much larger repertoire of coping-behaviors. IMPLICATIONS Fatigue countermeasures should include all levels of the driving task hierarchy, and experience-based countermeasures used by professional drivers should be considered for experimental validation.

Road Characteristics and Driver Fatigue: A Simulator Study

Two experiments examined the influence of road characterisitcs on driver fatigue in a prolonged simulator drive. In experiment one, ten military truck drivers drove a mixed route, with straight, winding, and straight highway segments. In experiment two, 16 additional drivers drove either a straight, a winding, or a mixed route. Fatigue symptoms were assessed using performance, subjective, and phsychophysiological measures (HRV). We hypothized that drivers adopt different fatigue-coping strategies relative to the demands of the drive. Thus, on straight roads drivers are more likely to loosen their driving demands by either increasing their driving speed and/or not maintaning the lane position, as the road is tolerant to both strategies, whereas on winding roads, drivers are more likely to increase their speed but not their lane positioning. Our results confirm that decremental changes in driving performance varied among road types. In the straight road components, we found decrements in the quality of lane maintaining (experiment one) and steering quality (experiments one and two) and longitudinal speed (experiment two). In the winding road, we found that drivers increased their driving speed over time (experiments one and two).

Evaluation of experience-based fatigue countermeasures

BACKGROUND AND OBJECTIVE Strategies adopted by drivers in order to cope with fatigue and falling asleep at the wheel include a variety of activities that may invigorate the body and/or the mind. The objectives of the current study were to examine the effectiveness of an energy drink and a non-traditional manual-dexterity/mastication activity as fatigue countermeasures. METHOD Twenty subjects participated in this driving simulator study. Each driving session lasted 2h and each driver drove under three conditions: after consumption of an energy drink, while engaged in a self-paced manual-dexterity/mastication secondary task (shelling and eating sunflower seeds), and in a control condition with neither. Fatigue effects were assessed on three dimensions: subjective evaluations (using the Swedish Occupational Fatigue Inventory), a physiological indicator (heart rate variability), and driving performance measures (speed, steering, and lane deviations). RESULTS The subjective and physiological measures showed a significant effect of both treatments in counteracting the effects of fatigue when compared to the control condition. The results of the driving performance measures indicated that the energy drink was effective in counteracting fatigue, while the secondary task was as effective as the energy drink in counteracting fatigue on measures that did not rely on hand movements. CONCLUSIONS Drinking an energy drink prior to the driving task has a significant, positive effect in counteracting fatigue, though it may have long-term negative rebound effects. The manual-dexterity/mastication secondary task can temporarily counteract the subjective and physiological effects of fatigue while driving, but can interfere with vehicle handling.

Vibrotactile “On-Thigh” Alerting System in the Cockpit

Background: Alerts in the cockpit must be robust, difficult to ignore, and easily recognized. Tactile alerts can provide means to direct the pilot’s attention in the already visual-auditory overloaded cockpit environment. Objective: This research examined the thigh as a placement for vibrotactile display in the cockpit. The authors (a) report initial findings concerning the loci and properties of the display, (b) evaluate the added value of tactile cuing with respect to the existing audio-visual alerting system, and (c) address the issue of tactile orienting—whether the cue should display “flight” or “fight” orienting. The tactor display prototype was developed by a joint venture of Israel Aerospace Industries, Lahav Division, and the Ben Gurion University of the Negev (patent pending 11/968,405). Method: A vibrotactile display mounted on the thigh provided directional cues in the vertical plane. Two vibrotactile display modes (eight and four tactors) and two response modes (compatible, i.e., fight [toward vibrotactile cue], and inverse, i.e., flight [away from vibrotactile cue]) were evaluated. Results: Vertical directional orienting can be achieved by a vibrotactile display assembled on the thigh. The four-tactor display mode and the compatible response mode produced more accurate results. Conclusion: Tactile cues can provide directional orienting in the vertical plane. The benefit of adding compatible tactile cues compared with visual and auditory cues alone has yet to be reinforced. Nevertheless, fight mode, that is, directing the way to escape from hazardous situations, was preferred. Application: Potential applications include providing directional collision alerts within the vertical plane, assisting pilot’s elevation control, or navigation.

The combination of short rest and energy drink consumption as fatigue countermeasures during a prolonged drive of professional truck drivers

One of the major concerns for professional drivers is fatigue. Many studies evaluated specific fatigue countermeasures, in many cases comparing the efficiency of each method separately. The present study evaluated the effectiveness of rest areas combined with consumption of energy drinks on professional truck drivers during a prolonged simulated drive. Fifteen professional truck drivers participated in three experimental sessions: control-drivers were asked to drink 500 ml of a placebo drink prior to the beginning of the drive. Energy drink-drivers were asked to drink 500 ml of an energy drink containing 160 mg of caffeine prior to the beginning of the drive, and an Energy drink+Rest session--where the drivers were asked to drink 500 ml of an energy drink prior to driving, and rest for 10 min at a designated rest area zone 100 min into the drive. For all sessions, driving duration was approximately 150 min and consisted of driving on a monotonous, two-way rural road. In addition to driving performance measures, subjective measures, and heart rate variability were obtained. Results indicated that consumption of an energy drink (in both sessions) facilitated lower lane position deviations and reduced steering wheel deviations during the first 80-100 min of the drive relative to the control sessions. Resting after 100 min of driving, in addition to the energy drink that was consumed before the drive, enabled the drivers to maintain these abilities throughout the remainder of the driving session. Practical applications: Practical applications arising from the results of this research may give indication on the possible added value of combining fatigue counter measures methods during a prolonged drive and the importance of the timing of the use for each method.

Alertness Maintaining Tasks While Driving

The purpose of the current study was to evaluate the effectiveness of different alertness maintaining tasks on driver performance. Twelve professional truck drivers participated in five sessions of simulated driving. The first session consisted of driving without any alertness-maintaining tasks. In the following three sessions, three different alertness maintaining tasks were given during the drive. The fifth session consisted of driving while listening to music. The analysis of the driving performance measures shows that overall alertness-maintaining tasks may have a positive effect on driving, by slowing performance deterioration and maintaining a higher level of alertness (measured by standardized HRV). Yet, not all tasks were equally demanding. Of the three tasks evaluated, the choice reaction time task was the least demanding and failed to prevent performance deterioration. A working memory task caused a decrement in longitudinal speed, perhaps indicating that it was too demanding for most drivers to perform while driving, and was subjectively evaluated by the drivers as the most detrimental task to the driving. A trivia game task did not show any advantage in preventing performance deterioration, but was preferred by 50% of the drivers over the other two tasks.

Vibrotactor-belt on the thigh: directions in the vertical plane

This multiple phase research examines the utility of the thigh as a placement for a vibrotactile display in the cockpit. The initial phase of this research is presented hereby. Vibrotactile displays designed to convey horizontal directional waypoints or warnings are commonly situated on the torso of the pilot. Here, an eight-tactors belt prototype fixed around the thigh of a seated operator was used to convey vertical directional waypoints. Localization accuracy was examined. Analysis revealed that vibrotactile cues embracing the thigh are discriminated in a similar manner to the torso, providing initial evidence that vibrotactile signaling on the thigh can provide directional cues in the vertical plane.

Comparison of three different techniques for camera and motion control of a teleoperated robot

This research aims to evaluate new methods for robot motion control and camera orientation control through the operators head orientation in robot teleoperation tasks. Specifically, the use of head-tracking in a non-invasive way, without immersive virtual reality devices was combined and compared with classical control modes for robot movements and camera control. Three control conditions were tested: 1) a condition with classical joystick control of both the movements of the robot and the robot camera, 2) a condition where the robot movements were controlled by a joystick and the robot camera was controlled by the user head orientation, and 3) a condition where the movements of the robot were controlled by hand gestures and the robot camera was controlled by the user head orientation. Performance, workload metrics and their evolution as the participants gained experience with the system were evaluated in a series of experiments: for each participant, the metrics were recorded during four successive similar trials. Results shows that the concept of robot camera control by user head orientation has the potential of improving the intuitiveness of robot teleoperation interfaces, specifically for novice users. However, more development is needed to reach a margin of progression comparable to a classical joystick interface.