Visual recognition analysis of optically long tunnels: interaction of dynamic vision and visual perception
To understand the relation between the geometric design of optically long tunnels and visibility of the exit area, in this study oculomotor (eye movement) data are collected from several drivers in Yunnan Province, China, and drivers’ fixation rate and saccade amplitude in the visible zone of the tunnel are measured as key indicators. The driver’s visual recognition is analyzed and key elements in the optimal design of the exit points of optically long tunnels are discussed. The results show that visual recognition is closely associated with the radius of the road curvature: as the radius of curve decreases, the visual focus is gradually attracted to the inner side of the curve, the proportion of small-angle saccade increases, and the dispersion of the saccade amplitude decreases.
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Comparative Data Analysis of Older Driver’s vs Younger Driver’s Gap Acceptance Behavior at signalized left turns-A driving Simulator Study
Drivers aged 65 and older are particularly prone to motor vehicle crashes, with approximately 20% of traffic fatalities occurring at intersections [11]. Intersections appear to be hazardous for drivers in this age group due to cognitive, perceptual, and psychomotor challenges. Older drivers find it particularly difficult to safely navigate left turns at signalized permissive intersections, having problems adequately detecting, perceiving, and accurately judging the safety of gaps. The increase in the number of elderly drivers has been paralleled by an increase in road-related accidents due to age-related fragility. By 2030, more than 21% of the adult population is projected to be over 65 years old [1]. However, previous studies have not adequately considered the combined effects of the randomized gap, queue length, traffic volume, pedestrians, and physiological factors on driving. The current study aims to address the gap in the literature by explicitly examining older and younger drivers’ gap acceptance behaviors during permissive left turns at four-way intersections. The main objective of this thesis is to study, identify and analyze the effect of Gap Acceptance Behavior on age, traffic volume, queue length, and physiological factors such as heart rate variability (HRV), electrodermal activity (EDA), and motion sickness among older and younger drivers. The data was collected from a driving simulator study comprising 40 participants aged between 20-30 for younger and 65 years for older. The collected data was used for comparative analysis, with the Gap Accepted by the drivers calculated from the video data. The gap is calculated as the distance between the left turning vehicle and the oncoming traffic. All recruited drivers were healthy. Each participant navigated twelve scenarios, six with lower traffic conditions and six with higher traffic conditions. Each lower and higher traffic scenario varied in queue length, with the number of cars in front of the ego vehicle varying from 0, 1, and 2. All varying queue lengths also had one with a pedestrian and another without. The physiological data collected through the Empatica4 wristband was also considered to study the gap acceptance behavior. Another parameter, motion sickness susceptibility score (MSSQ), was obtained from a questionnaire the participants completed after the experiment. Of these factors, queue length, traffic volume, and pedestrians play a significant role in studying gap acceptance. There is a significant difference in accepting and rejecting the gap between young and older drivers. Older drivers’ decision is affected more by factors, such as traffic volume, age, queue length, HRV, EDA, MSSQ score and the presence of pedestrians. This study showed that older drivers exhibited longer gap acceptance times than their younger counterparts while turning left across traffic at permissive intersections. Researchers may use the findings to better understand gap acceptance behaviors, while policymakers may utilize the results to design mobility guidelines.
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Correlation between driver visual characteristics and lane change parameters in urban long-term work zone
To investigate the correlation between drivers' visual characteristics and lane change parameters in urban long-term work zone, firstly, this paper obtains the oculomotor parameters of different drivers in urban long-term operation areas through real vehicle experiments and concludes that the pupil area and saccade angel of drivers in warning area and upstream transition area road sections have significant differences within 95% confidence interval by one-way ANOVA method. Next, scatter plots of lane change behavior parameters and eye movement parameters were plotted and validated by the Person correlation statistics method to find that: In the warning zone section, the driver's pupil area was negatively correlated with running speed, distance from the latest lane change point, and lateral displacement acceleration to varying degrees, with the strongest correlation with distance from the latest lane change point, |г|=0.816; the saccade angel was correlated with running speed and lateral displacement acceleration, with the strongest correlation with running speed, |г|=0.667. In the upstream transition zone section, the driver's pupil area was negatively correlated with all three lane change parameters to varying degrees, with the strongest correlation with the distance from the latest lane change point, |г|=0.512; the saccade angel was correlated with the distance from the latest lane change point, |г|=0.538, with no significant correlation with the running speed and lateral displacement acceleration.
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Simulator
How do drivers allocate visual attention to vulnerable road users when turning at urban intersections?
Drivers turning at urban intersections pose a high risk to Vulnerable Road Users (VRUs), such as cyclists and pedestrians. In vehicle collisions with VRUs, driver attention misallocation is considered a leading contributor. While previous naturalistic studies have examined driver gaze behaviors at intersections, findings are limited to general gaze directions obtained through video analysis, meaning specific areas to which drivers attend cannot be determined. We present a secondary analysis of an on-road instrumented vehicle dataset collected in 2019 which offers eye-tracking and video data from 26 experienced drivers (13 cyclists and 13 non-cyclists). Three coders jointly examined eye-tracking footage from four right-signalized turns (n=96) to quantify drivers’ glance distributions to various areas of interest, including those most relevant to VRU safety when drivers turn. Individual temporal glance patterns and general attention allocation trends are presented and described. (1) Relevant pedestrians were the top objects of glance irrespective of signal status, and (2) at red light turns, driver attention was heavily skewed toward leftward traffic. This analysis provides a detailed report of driver glance distributions toward scene-specific areas (as opposed to general directions) at urban intersections and discusses how these patterns may influence VRU safety.
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Simulator
Hypoxia impairs reaction time but not response accuracy in a visual choice reaction task
We investigated the effect of hypoxia on the reaction time (RT) and response accuracy of pilots performing a visual choice reaction task that corresponded to the scanning of helmet mounted display (HMD) symbology. Eighteen male military pilots performed the task in a hypobaric chamber at two simulated altitudes (92 m and 4572 m) in a single-blinded repeated measures and counter-balanced design. The visual stimuli were displayed in low and high contrast and at a 30- and 50-degree field of view (FoV). We measured the pilots' RT and response accuracy. Using an eye tracker, we measured the pilot's glance time at each stimulus location. Finally, we collected subjective ratings of alertness. The results show that hypoxia increased the RT and glance time. Lowering the stimulus contrast and increasing the FoV further increased the RT, independent of hypoxia. These findings provide no evidence for hypoxia-induced changes in visual contrast sensitivity or visual field. Instead, hypoxia seemed to affect RT and glance time by reducing alertness. Despite the increased RT, the pilots maintained their accuracy on the visual task, suggesting that visual scanning of HMD symbology may be resistant to the effects of acute hypoxia.
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Improving Driving Automation Training Through Scaffolding of Roles and Responsibilities Information: A Comparison between Older and Younger Drivers
Adaptive Cruise Control (ACC) is an Advanced Driver Assistance System (ADAS) commonly found in new vehicles that shares the responsibilities of maintaining headway and speed. However, drivers often have a limited understanding of their roles and responsibilities and how they should modify their behaviors when driving with ACC. This study investigates the effect of scaffolding teaching technique by providing additional background knowledge about ACC and highlighting drivers’ new roles and responsibilities for both older and younger adults during text-based ACC training programs. The study also initiates a new approach to evaluate drivers’ learning outcomes at different stages of driving automation training (i.e., reading behavior during training, post-training knowledge test, gaze monitoring behavior, and driving performance during simulated driving). Thirty-nine participants (20 younger + 19 older) received one of the two ACC training protocols: basic (system functionality, operational procedures, and limitations) and comprehensive (basic training + ACC background information and driving roles and responsibilities). The results showed that the comprehensive training led to reduced reading page revisits and adjusted workload during training, better performance in post-training knowledge tests, and more ACC engagement during simulated driving. The findings also suggested the feasibilities and connections within the new training evaluation approach that can provide insights into understanding ACC training outcomes through different stages. Future research is needed to further explore the effect of scaffolding teaching method on trainees’ learning-behavioral translation and the application of the new training evaluation approach to support experimental design or other in-vehicle technologies.
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Pilot study: Effect of roles and responsibility training on driver’s use of adaptive cruise control between younger and older adults
With the development of driver support systems (SAE Levels 1 – 2), drivers must take on new monitoring and supervision tasks in additional to manual driving. Training is necessary to clarify drivers' new roles and promote safe usage and trust in these systems. Providing training for lower-levels of automation may also benefit drivers’ acceptance of future Fully Automated Vehicles (FAVs, SAE Level 5). However, younger and older drivers differ in training preferences (e.g., owner's manual vs on-road trial and error) and hold different attitudes towards automation. This study investigates the effects of additional training on drivers' roles and responsibilities when using Adaptive Cruise Control (ACC, SAE Level 1) for younger and older drivers. Thirty-nine adults (20 younger + 19 older) were trained on one of two ACC training protocols: basic (system functionality, operational procedures, and limitations) and comprehensive (basic training + ACC background and roles of responsibilities). Participants’ situational trust and ACC usage was evaluated before, during, and after experiencing an emergency event while using ACC in a driving simulator study. Results showed that the comprehensive training promoted drivers' situational trust in ACC, ACC usage, and the acceptance of FAVs. Compared to younger drivers, older drivers used ACC less, reported less dynamic situational trust, higher levels of workload, and lower acceptance. Overall, comprehensive training resulted in older drivers behaving similarly to younger drivers. The comprehensive training also promoted the acceptance of FAVs for both younger and older drivers. In conclusion, training of drivers’ roles and responsibilities has an impact on drivers’ usage of ACC and may be particularly useful for older drivers.
Texting while driving: a literature review on driving simulator studies
Road safety is increasingly threatened by distracted driving. Studies have shown that there is a significantly increased risk for a driver of being involved in a car crash due to visual distractions (not watching the road), manual distractions (hands are off the wheel for other non-driving activities), and cognitive and acoustic distractions (the driver is not focused on the driving task). Driving simulators (DSs) are powerful tools for identifying drivers’ responses to different distracting factors in a safe manner. This paper aims to systematically review simulator-based studies to investigate what types of distractions are introduced when using the phone for texting while driving (TWD), what hardware and measures are used to analyze distraction, and what the impact of using mobile devices to read and write messages while driving is on driving performance. The review followed the Preferred Reporting Items for Systematic Reviews and Meta-Analysis extension for Scoping Reviews (PRISMA-ScR) guidelines. A total of 7151 studies were identified in the database search, of which 67 were included in the review, and they were analyzed in order to respond to four research questions. The main findings revealed that TWD distraction has negative effects on driving performance, affecting drivers’ divided attention and concentration, which can lead to potentially life-threatening traffic events. We also provide several recommendations for driving simulators that can ensure high reliability and validity for experiments. This review can serve as a basis for regulators and interested parties to propose restrictions related to using mobile phones in a vehicle and improve road safety.
Transportation Research Interdisciplinary Perspectives
Introduction: Drivers turning at urban intersections pose a high risk to Vulnerable Road Users (VRUs), such as cyclists and pedestrians. In vehicle collisions with VRUs, driver attention misallocation is considered a leading contributor. While previous naturalistic studies have examined driver gaze behaviors at intersections, findings are limited to general gaze directions obtained through video analysis, meaning specific areas to which drivers attend cannot be determined. Method: We present a secondary analysis of an on-road instrumented vehicle dataset collected in 2019 which offers eye-tracking and video data from 26 experienced drivers (13 cyclists and 13 non-cyclists). Three coders jointly examined eye-tracking footage from four right-signalized turns (n = 96) to quantify drivers’ glance distributions to various areas of interest, including those most relevant to VRU safety when drivers turn. Individual temporal glance patterns and general attention allocation trends are presented and described. Results: (1) Relevant pedestrians were the top objects of glance irrespective of signal status, and (2) at red light turns, driver attention was heavily skewed toward leftward traffic. Conclusions: This analysis provides a detailed report of driver glance distributions toward scene-specific areas (as opposed to general directions) at urban intersections and discusses how these patterns may influence VRU safety. Practical applications: This study provides important information regarding the human factors challenges of vehicle-VRU collisions and their prevention.
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