729 research outputs found
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Human-Vehicle Interfaces: The Power of Vehicle Movement Gestures in Human Road User Coordination
No full textAutonomous vehicles will have to coordinate their behavior with human road users such as drivers and pedestrians. The majority of recently proposed solutions for autonomous vehicle-to-human communication consist of introducing additional visual cues (such as lights, text and pictograms) on either the car’s exterior or as projections on the road. We argue that potential shortcomings in the visibility (due to light conditions, placement on the vehicle) and immediate understandability (learned, directive) of many of these cues make them alone insufficient in mediating multi-party interactions in the busy intersections of day-to-day traffic. Our observations of real-world human road user behavior in urban intersections indicate that movement in context is a central method of communication for coordination among drivers and pedestrians. The observed movement patterns gain meaning when seen within the context of road geometry, current road activity, and culture. While all movement communicates the intention of the driver, we highlight the use of movement as gesture, done for the specific purpose of communicating to other road users and give examples of how these influence traffic interactions. An awareness and understanding of the effect and importance of movement gestures in day-to-day traffic interactions is needed for developers of autonomous vehicles to design forms of human-vehicle communication that are effective and scalable in multi-party interactions
Contextualizing Naturalistic Driving Data in a Rural State Among Drivers With and Without Obstructive Sleep Apnea
No full textIn naturalistic studies, Global Positioning System (GPS) data and date/time stamps can link driver exposure to specific environments (e.g., road types, speed limits, night driving, etc.), providing valuable context for analyzing critical events, such as crashes, near crashes, and breaches of accelerometer limits. In previous work, we showed how to automate this contextualization, using GPS data obtained at 1 Hz and merging this with Geographic Information Systems (GIS) databases maintained by the Iowa Department of Transportation (DOT). Here we further demonstrate our methods by analyzing data from 80 drivers with obstructive sleep apnea (OSA) and 48 controls, and comparing the two groups with respect to several factors of interest. The majority of comparisons found no difference between groups, suggesting similar patterns of exposures to driving environments in OSA and control drivers. However, OSA drivers appeared to spend slightly more time on roads with annual traffic counts of 500-10,000 and less time driving on wider highways, during twilight, and on roads with 10,000-25,000 annual traffic counts
Determinants of Performance on Specific On-Road Skills in Multiple Sclerosis
No full textIn this prospective cross-sectional study, we investigated the cognitive, visual, and motor deficits underlying poor performance during on-road driving in 102 individuals with multiple sclerosis (MS). Thirteen specific skills categorized into hierarchic clusters of operational, tactical, visuo-integrative, and mixed driving were assessed during the on-road evaluation. Stepwise regression analysis identified the off-road skills that influenced overall performance on the on-road test and in each cluster. Study results showed that visuospatial function (p=0.002), inhibition (p=0.008), binocular acuity (p=0.04), vertical visual field (p=0.02), and stereopsis (p=0.03) together accounted for the highest variance in total on-road score (R2 =0.37). Attentional shift (p=0.0004), stereopsis (p=0.007), glare recovery (p=0.047), and use of assistive devices (p=0.03) best predicted the operational cluster (R2 =0.28). Visuospatial function p=0.002), inhibition (p=0.002), reasoning (p=0.003), binocular acuity (p=0.04), and stereopsis (p=0.005) best determined the tactical cluster (R2 =0.41). The visuo-integrative model (R2 =0.12) comprised binocular acuity (p=0.007) and stereopsis (p=0.045). Inhibition (p=0.0001) and binocular acuity (p=0.001) provided the best model of the mixed cluster (R2 =0.25). These results provide more insights into the specific impairments that influence different dimensions of on-road driving and may be used as a framework for targeted driving intervention programs in MS
Hazard Perception Test (HPT): A Pilot Study in Brazil
No full textTraffic collisions are a major cause of violent death and disability worldwide (Goldman & Ausiello, 2009). In developing countries, mortality rates are significantly higher when compared to other countries. In Brazil, official data show 23.4 fatalities per 100,000 inhabitants, compared to 10.6 in the United States and 6.0 in Canada (Global Status Report on Road Safety, 2015). Driving requires specific motor and cognitive skills, such hazard perception. The Hazard Perception Test (HPT) assesses a drivers' ability to identify or anticipate dangerous situations in traffic (Horswill & McKenna, 2004) and taps into different cognitive processes, such as speed to detect the hazard, judgment of hazard severity, and decision-making. The HPT has been directly associated with the risk of collision (Darby et al, 2009; McKenna & Horswill, 1999; Quimby et al, 1986; Wells et al, 2008). Many countries, such as Australia and Great Britain, have made hazard perception a regular component of the driving test. In Brazil, however, candidates undergo an exam that has the characteristics of a clinical screening and does not assess context-specific cognitive abilities. Thus, there is a clear demand for clinical procedures with greater diagnostic sensitivity that address fundamental abilities such as hazard perception. The goal of the study was to employ an adapted version of the static Hazard Perception Test (s-HPT) under standardized Brazilian conditions. Results indicated that drivers' ability to perceive hazards is clearly dependent on variables such as expertise, age, and gender. The results are in accordance with previous studies conducted in other countries
Using Situation Awareness as a Measure of Driver Hazard Perception Ability
No full textThe present study investigated the effectiveness of a tablet-based hazard anticipation training program on teenage drivers. Verbal and eye tracking protocols were mapped to Endsley’s three level model of situation awareness (SA) as a means of measuring schema development. Participants were trained with a tablet based training program containing hazard identification scenarios. After six months they were asked to drive a simulator and on-road drive with various hazard scenarios. Results showed a significant difference between trained teen drivers and placebo teen drivers, both in eye tracking and verbal protocol. Verbal protocol and eye tracking protocol of trained teen drivers showed higher order of situation awareness in either of Endsley’s model levels. This means trained group were more capable of identifying and mitigating the hazards and verbalizing the future states of the environment. In conclusion, the tablet based hazard identification and anticipation training program could be an effective post-licensure training program to give better insight of “what is going on” in driving environment
The Effects of Guidance Method on Detection and Scanning at Intersections – A Pilot Study
No full textOlder drivers are frequently involved in collisions at intersections. One reason may be inadequate head and eye scanning when approaching the intersection. Prior driving simulator research on scanning at intersections has employed two main methods to guide subjects through the simulated world: auditory instructions similar to GPS navigation and following a lead vehicle. However, these two methods may have differing effects on head and eye scanning behaviors. We therefore conducted a pilot study to assess the effects of guidance method on participants’ head and eye movements as well as their detection of motorcycle hazards at intersections. Detection rates were significantly higher when following a lead vehicle than when following GPS instructions, but participants were closer to the intersection when they responded. Preliminary examination of the head and eye movement data suggests participants scanned less frequently when following the lead vehicle
Following Expert’s Eyes: Evaluation of the Effectiveness of a Gaze-Based Training Intervention on Young Drivers’ Latent Hazard Anticipation Skills
No full textA PC-based training program (RAPT; Pradhan et al., 2009), proven effective for improving young novice drivers’ hazard anticipation skills, does not improve the hazard anticipation performance of young drivers to ceiling despite the use of similar scenarios in both the training program and the evaluation drives. The current driving simulator experiment examined the effects of expert eye movement videos that demonstrated correct hazard anticipation, following RAPT-training on young drivers’ hazard anticipation performance. The results indicate that viewing the expert eye movement videos following the completion of RAPT can further increase the hazard anticipation ability of young drivers on subsequent evaluation drives. The results imply that videos of expert eye movements, if used appropriately, can help young drivers effectively map and integrate the knowledge gained in a training program within dynamic driving environments involving latent hazards
Evaluating Drivers’ States in Sleepiness Countermeasures Experiments Using Physiological and Eye Data – Hybrid Logistic and Linear Regression Model
No full textObjective sleepiness evaluation is essential for the effect analysis of countermeasures for driver sleepiness, such as in-car stimulants. Furthermore, measuring drivers’ sleepiness in simulator studies also becomes important when investigating causes for task-related sleepiness, for example driving on monotonous routes, which requires little driver engagement. To evaluate driver sleepiness and the effect of countermeasures, we developed a model for predicting sleepiness using both simple logistic and linear regression of heart rate variability, skin conductance and pupil diameter. The algorithm was trained and tested with data from 88 participants in driving simulator studies. A prediction accuracy of 77% was achieved and the model’s sensitivity to thermal stimulation was shown
Exploring Driver Responses to Unexpected and Expected Events Using Probabilistic Topic Models
No full textDrivers’ expectations influence their responses to events in complex ways. In particular, covert and sustained hazards, like crosswinds, might require complex vehicle control adaptations. We investigated differences between drivers’ lateral responses in unexpected and expected (repeated) crosswind events using probabilistic topic modeling. First, each driver’s event-based steering wheel movements (angle and rate, 5 Hz) were transformed into symbolic words. Then, probabilistic topic modeling was used to discover patterns in the steering wheel movement data across the event conditions. Results indicate that drivers may make fewer abrupt steering wheel movements when they encounter unexpected crosswinds. On the contrary, drivers are more likely to make continuous faster steering corrections to compensate crosswinds when they are expected. The topic models also classify unexpected and expected crosswind events better than traditional models that use single aggregated values across events (maximum steering wheel angle and rate). These preliminary insights show an advantage for granular, time-series based analysis of driving data, and suggest a viable machinelearning based technique to conduct such investigations
A New Method for Estimating Effects of Visual Field Loss in a Panoramic Driving Environment
No full textGlaucoma is a key cause of peripheral visual field loss and increases risk of a vehicle crash. Patients may be unaware of their visual loss and of hazards in the driving panorama. Standard clinical automated perimetry, the “gold standard” for monitoring glaucoma progression, lacks external validity to evaluate functional effect of visual field loss in driving environments. We developed and piloted a new technique to study the effects of glaucoma in a panoramic (290 forward FOV) simulated driving environment. Preliminary results in 11 drivers (7 with glaucoma and 4 with suspected glaucoma): (1) demonstrate the relationship between standard clinical perimetry and driving simulator visual fields, (2) replicate clinical evidence of glaucoma-related peripheral visual field loss, and (3) show added visual field loss due to visual occlusion by in-cab geometry