Time-to-contact estimation errors among older drivers with useful field of view impairments

Impacts of brightness contrast, road environment complexity, travel direction and judgement type on speed perception errors among older adult pedestrians' road-crossing decision-making

OBJECTIVES

This study aimed to explore how various factors affect older people's vehicle speed perception to enhance their road safety as pedestrians, focusing on the impact of their cognitive and perceptual abilities on road-crossing decisions.

METHODS

The study evaluated the effects of brightness contrast (high, medium and low), road complexity (high and low) and vehicle travel direction (same and opposite) on speed perception errors in simulated traffic settings. It involved 38 older participants who estimated the speed of a comparison vehicle under two judgement conditions.

RESULTS

Findings showed a consistent underestimation of speed in all conditions. A repeated-measure ANOVA revealed that speed perception errors were significantly higher with low brightness contrast, in simpler road environments, with vehicles travelling in the same direction, and when using absolute judgements.

CONCLUSIONS

These results have practical importance for public safety initiatives, traffic regulation and road design catering to older adults' perceptual needs. They also provide valuable insights for driver training programs for older adults, aimed at enhancing their understanding and management of perceptual biases.

Does connected environment contribute to the driving safety and traffic efficiency improvement in emergency events?

A connected environment is crucial for improving road traffic safety and efficiency. However, it remains unclear how different connected environments affect the interaction between vehicles and their impact on driving safety and traffic efficiency in scenarios with potential risks, such as forced lane changes during emergency events. To investigate the effects of different connected environments on drivers' interaction characteristics and their impact on driving safety and traffic efficiency, a group of simulated driving test was implemented in a multi-agent interactive intelligent connected vehicle driving simulation platform. Four types of connected environments were designed, Non-Connected Vehicles (NCV), Front Vehicle Single-Connected Vehicles (FCV), Rear Vehicle Single-Connected Vehicles (RCV), and Double-Connected Vehicles (DCV). Additionally, four different initial headways were tested (10 m, 20 m, 30 m, and 40 m). 40 drivers were recruited to participate in driving simulation experiments, and simulated driving data were collected. The research results indicate that for the front vehicle (FV), connectivity significantly reduces the collision risk with the accident vehicle (TTCFCV = 4.238 s, TTCDCV = 4.385 s), decreases the maximum longitudinal deceleration of FV (FCV = -1.212 m/s2, DCV = -1.022 m/s2), and reduces the speed fluctuation of FV (FCV = 4.748 km/h, DCV = 3.784 km/h). For the rear vehicle (RV), benefits are observed only in the FCV environment, where connectivity helps reduce the maximum deceleration of RV (FCV = -1.545 m/s2), decrease its speed fluctuation (FCV = 3.852 km/h), and enhance overall traffic efficiency (FCV = 12.133 s). Additionally, the minimum time difference to collision (TDTC) in the RCV environment (2.679 s) is significantly higher compared to other connected environments, and the number of cases with TDTC < 1.5 s (49) is notably lower than in other connected environments (NCV = 101, FCV = 107, DCV = 80). This suggests that the RCV environment effectively reduces the lateral collision risk during lane changes. Overall, while single-vehicle connectivity may help reduce driving risks and improve traffic efficiency, DCV may not significantly enhance vehicle safety and traffic efficiency. When the vehicle headway between FV and RV is 20 m (1.651 s), lateral conflicts between the vehicles are most severe. The maximum longitudinal deceleration of FV and RV also significantly decreases with increasing vehicle headway, and when the vehicle headway exceeds 30 m, the maximum longitudinal deceleration of RV nearly ceases to decrease (-1.993 m/s2 at 30 m, -1.948 m/s2 at 40 m). As the distance between the front and rear vehicles (DHWFV-RV) increases, the speed of FV becomes more stable, particularly when DHWFV-RV is 40 m (M = 4.204 km/h), where the speed fluctuations of FV are significantly lower compared to other vehicle headways. A 30-meter vehicle headway (M = 5.684 km/h) is more effective in maintaining speed stability for RV. Although travel time increases with the increase in DHWFV-RV, this change does not show a significant difference. Overall, to ensure traffic efficiency, a vehicle headway of 30 m generally satisfies lane-change safety requirements and provides more stable vehicle speed and acceleration.

Quantifying accuracy on distance estimation tasks: A Monte Carlo study

An important aspect of perceptual learning involves understanding how well individuals can perceive distances, sizes, and time-to-contact. Oftentimes, the primary goal in these experiments is to assess participants' errors (i.e., how accurately participants perform these tasks). However, the manner in which researchers have quantified error, or task accuracy, has varied. The use of different measures of task accuracy, to include error scores, ratios, and raw estimates, indicates that the interpretation of findings depends on the measure of task accuracy utilized. In an effort to better understand this issue, we used a Monte Carlo simulation to evaluate five dependent measures of accuracy: raw distance judgments, a ratio of true to estimated distance judgments, relative error, signed error, and absolute error. We simulated data consistent with prior findings in the distance perception literature and evaluated how findings and interpretations vary as a function of the measure of accuracy used. We found there to be differences in both statistical findings (e.g., overall model fit, mean square error, Type I error rate) and the interpretations of those findings. The costs and benefits of utilizing each accuracy measure for quantifying accuracy in distance estimation studies are discussed.

Different deployments of attentional breadth selectively predict UFOV task performance in older adults

The Useful Field of View task (UFOV) is a strong and reliable predictor of crash risk in older drivers. However, while the functional domain of attention is clearly implicated in UFOV performance, the potential role of one specific attentional process remains unclear: attentional breadth (the spatial extent of the attended region around the point of visual fixation). The goal of the present study was to systematically test the role of two distinct aspects of attentional breadth, maintaining a specific breadth of attention and resizing the attended region, in UFOV performance. To this end, 135 older adults completed the UFOV and modified Navon tasks to measure their efficiency in maintaining, contracting, and expanding the breadth of attention. We then examined individual-difference associations between these aspects of attentional breadth deployment and UFOV performance. We found that performance on UFOV Subtask 2 was associated with efficient contraction of attentional breadth (i.e., resizing the attended region to a smaller area), while Subtask 3 performance was associated with the efficiency of expanding attentional breadth (i.e., resizing the attended region to a larger area). The selectivity of these relationships appears to implicate these specific deployments of attentional breadth in how people complete the task, as it suggests that these relationships are not simply attributable to shared variance in a broader domain of cognitive functioning. The implications of these results for our understanding of UFOV, as well as future research directions that test the relative contributions of different cognitive processes in predicting task performance, are discussed.

Ecological Values Theory: Beyond Conformity, Goal-Seeking, and Rule-Following in Action and Interaction

Values have long been considered important for psychology but are frequently characterized as beliefs, goals, rules, or norms. Ecological values theory locates them, not in people or in objects, but in ecosystem relationships and the demands those relationships place on fields of action within the system. To test the worth of this approach, we consider skilled coordination tasks in social psychology (e.g., negotiating disagreements, synchrony and asynchrony in interactions, and selectivity in social learning) and perception-action (e.g., driving vehicles and carrying a child). Evidence suggests that a diverse array of values (e.g., truth, social solidarity, justice, flexibility, safety, and comfort) work in a cooperative tension to guide actions. Values emerge as critical constraints on action that differ from goals, rules, and natural laws, and yet provide the larger context in which they can function effectively. Prospects and challenges for understanding values and their role in action, including theoretical and methodological issues, are considered.

Time-to-Collision Estimations in Young Drivers with Autism Spectrum Disorder and Attention-Deficit/Hyperactivity Disorder

Individuals with attention-deficit/hyperactivity disorder (ADHD) and autism spectrum disorder (ASD) may exhibit driving difficulties due to cognitive impairments such as time perception difficulties, a construct related to the perception of time-to-collision (TTC). This study examined the timing abilities of drivers with ASD and ADHD. Sixty participants (n_ADHD = 20, n_ASD = 20, n_TD = 20) completed a time reproduction task and a TTC estimation task in a driving simulator. Results indicated drivers with ASD were less precise in time reproduction across all time intervals and over-reproduced time at shorter intervals. Drivers with ASD produced larger TTC estimates when driving at a faster speed compared to typically developing drivers. Drivers with ASD, but not ADHD, appear to present difficulties in time estimation abilities.

Time-to-arrival estimations to simulated pedestrians

Driving a vehicle requires individuals' awareness of their surroundings to prevent collisions with other vehicles, objects, and pedestrians. While previous research has investigated time-to-arrival (TTA) in real-world and simulated driving situations, there is little information on how pedestrian reflectance and time of day impact TTA. The present study investigated how vehicle velocity, viewing time, pedestrian reflectance, and time of day affected individuals' estimates of TTA. We used recorded driver-perspective footage of a vehicle approaching simulated pedestrians at different velocities during daytime and nighttime. We found that TTA was consistently underestimated, with the most accurate TTA estimates occurring at the lowest vehicle velocity. We also found TTA accuracy was better during daytime conditions. Pedestrian reflectance did not produce a significant main effect, but it did interact significantly with both velocity and time of day. These results suggest that multiple variables are responsible for TTA estimation. A better understanding of what factors may affect TTA estimates helps both researchers who investigate the phenomenon and laypersons who strive for safe driving practices.

Effects of aging on foot pedal responses to visual stimuli

BACKGROUND

Car accidents due to unexpected forward or backward runaway by older drivers are a serious social problem. Although the cause of these accidents is often attributed to stepping on the accelerator instead of the brake, it is difficult to induce such pedal application errors systematically with usual drive simulators. We developed a simple personal computer system that induces the pedal errors, and investigate the effects of age on the error behaviors.

METHODS

The system consisted of a laptop computer and a three-pedal foot mouse. It measured response time, accuracy, and flexibility of pedal operation to visual stimuli. The system displayed two open circles on the computer display, lighting one of the circles in a random order and interval. Subjects were instructed to press the foot pedal with their right foot as quickly as possible when the circle was lit; the ipsilateral pedal to the lit circle in a parallel mode and the contralateral pedal in a cross mode. When the correct pedal was pressed, the light went off immediately, but when the wrong pedal was pressed, the buzzer sounded and the light remained on until the correct pedal was pressed. During a 6-min trial, the mode was switched between parallel and cross every 2 min. During the cross mode, a cross mark appears on the display. The pedal responses were evaluated in 52 subjects divided into young (20-29 years), middle-aged (30-64 years), and older (65-84 years) groups. Additionally, the repeatability of the pedal response characteristic indicators was examined in 14 subjects who performed this test twice.

RESULTS

The mean response time was 95 ms (17%) longer in the older group than in the young group. More characteristically, however, the older group showed 2.1 times more frequent pedal errors, fell into long hesitations (response freezing > 3 s) 16 times more often, and took 1.8 times longer period to correct the wrong pedal than the young groups. The indicators of pedal response characteristics showed within-individual repeatability to the extent that can identify the age-dependent changes.

CONCLUSIONS

Hesitations and extended error correction time can be associated with increased crash risk due to unexpected runaway by older drivers. The system we have developed may help to uncover and evaluate physiological characteristics related to crash risk in the elderly population.

Clinical provision of compensatory visual training after neurological injury: example of a multisite outpatient program

AIM

Treatment efficacy is established via controlled research trials, but treatment in real-world clinical environments is typically highly variable and may differ from research protocols by necessity. Here, we examined provision of visual retraining for adults after neurological injury at an outpatient rehabilitation program in Calgary, Canada.

METHODS

Retrospective chart audits extracted demographic data, assessment outcomes, and details related to provision of training.

RESULTS

Treatment was provided to individuals with both visual field and visual-perceptual impairments due to neurological injury (mostly stroke). Tools and techniques of visual retraining at this program are discussed, the common denominator being repetitive practice of compensatory visual behaviors. Across this multisite program, there was significant variability in the number of treatment sessions, 13.00 (±10.21) sessions for those with visual-perceptual impairments and 14.41 (±9.63) sessions for those with field loss. Descriptive statistics and confidence intervals suggest improved outcomes on some measures for those with visual field and visual perceptual impairments.

CONCLUSIONS

Our data suggest that visual retraining is feasible in this clinical outpatient setting. Implications for rehabilitation This program of visual retraining was provided to individuals with visual impairment (e.g., hemianopia) and visual perceptual impairment (e.g., unilateral spatial neglect) as a result of neurological injury. In this outpatient program, visual rehabilitation was feasible and appeared to improve outcomes among a heterogeneous clinical population. Fundamental characteristics of visual compensatory training at this program included repetitive practice of adaptive scanning behaviors across multiple contexts to promote automaticity and generalization of skills.

Older adults display diminished error processing and response in a continuous tracking task

Advancing age is often accompanied by a decline in motor control that results in a decreased ability to successfully perform motor tasks. While there are multiple factors that contribute to age-related deficits in motor control, one unexplored possibility is that age-related deficits in our ability to evaluate motor output result in an increase in motor errors. In line with this, previous work from our laboratory demonstrated that motor errors evoked an error-related negativity (ERN)-a component of the human ERP associated with error evaluation originating within the human medial-frontal cortex. In the present study, we examined whether or not deficits in the medial-frontal error evaluation system contribute to age-related deficits in motor control. Two groups of participants (young, old) performed a computer-based tracking task that paralleled driving while EEG data were recorded. Our results show that older adults committed more behavioral errors than young adults during performance of the tracking task. An analysis of our ERP data revealed that the amplitude of the ERN was reduced in older adults relative to young adults following motor errors. Our results make an important extension from previous work demonstrating age-related reductions in the ERN during performance of cognitive tasks. Importantly, our results imply the possibility of understanding motor deficits in older age.