Browsing by Author "Weaver, Bradley W."

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    A Systematic Review and Meta-Analysis of Takeover Performance During Conditionally Automated Driving
    (Sage, 2022) Weaver, Bradley W.; DeLucia, Patricia R.
    Objective: The aim of this paper was to synthesize the experimental research on factors that affect takeover performance during conditionally automated driving. Background: For conditionally automated driving, the automated driving system (ADS) can handle the entire dynamic driving task but only for limited domains. When the system reaches a limit, the driver is responsible for taking over vehicle control, which may be affected by how much time they are provided to take over, what they were doing prior to the takeover, or the type of information provided to them during the takeover. Method: Out of 8446 articles identified by a systematic literature search, 48 articles containing 51 experiments were included in the meta-analysis. Coded independent variables were time budget, non-driving related task engagement and resource demands, and information support during the takeover. Coded dependent variables were takeover timing and quality measures. Results: Engaging in non-driving related tasks results in degraded takeover performance, particularly if it has overlapping resource demands with the driving task. Weak evidence suggests takeover performance is impaired with shorter time budgets. Current implementations of information support did not affect takeover performance. Conclusion: Future research and implementation should focus on providing the driver more time to take over while automation is active and should further explore information support. Application: The results of the current paper indicate the need for the development and deployment of vehicle-to-everything (V2X) services and driver monitoring.
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    Effect of motorcycle lighting configurations on drivers’ perceptions of closing during nighttime driving
    (Elsevier, 2022) Weaver, Bradley W.; DeLucia, Patricia R.
    Objective: The aims were to better understand how drivers perceive an approaching set of motorcycle headlights during nighttime driving and to determine whether alternative motorcycle headlight configurations improve drivers’ perceptual judgments of closing for an oncoming motorcycle. Background: Motorcyclists account for a disproportionate number of roadway fatalities, especially at night. One potential cause of this is drivers’ misjudgments of a motorcycle’s approach. Method: The first experiment examined whether drivers were more sensitive to horizontal or vertical optical expansion and whether drivers could integrate these two dimensions to achieve a lower looming threshold. A second experiment built on these results to test whether alternative headlight configurations that maximized size were better than other motorcycle headlight configurations and a car’s headlights. In both experiments, participants were instructed to press a button to indicate when they first perceived an oncoming vehicle to be closing under nighttime driving conditions. Results: Headlight orientation did not affect when drivers perceived closing, and drivers were not able to integrate optical expansion from multiple dimensions in a way that achieves a lower looming threshold. However, the alternative motorcycle headlight configurations that accentuated the full extent of a motorcycle’s size resulted in drivers perceiving closing sooner than other motorcycle headlight configurations but not sooner than a car. Conclusion: Drivers perceive closing sooner for larger headlight configurations except when the headlight configurations are relatively small, in which case the effect of headlight size is attenuated. Application: Drivers’ perceptual judgments of motorcycles may improve when motorcycles have headlights that span its full height.
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    Factors That Affect Drivers' Perception of Closing and an Immediate Hazard
    (Sage, 2023) Weaver, Bradley W.; DeLucia, Patricia R.; Jupe, Jason
    Objective: To measure the looming threshold for when drivers perceive closing and an immediate hazard and determine what factors affect these thresholds. Background: Rear-end collisions are a common type of crash. One key issue is determining when drivers first perceive they need to react. The looming threshold for closing and an immediate hazard are critical perceptual thresholds that reflect when drivers perceive they need to react. Method: Two driving simulator experiments examined whether engaging in a cell phone conversation and whether the complexity of the roadway environment affect these thresholds for the perception of closing and immediate hazard. Half of the participants engaged in a cognitive task, the last letter task, to emulate a cell phone conversation, and all participants experienced both simple and complex roadway environments. Results: Drivers perceived an immediate hazard later when engaged in a cell phone conversation than when not engaged in a conversation but only when the driving task was relatively less demanding (e.g., simple roadway, slow closing velocity). Compared to simple scenes, drivers perceived closing and an immediate hazard later for complex scenes but only when closing velocity was 30 mph (48.28 km/h) or greater. Conclusion: Cell phone conversation can affect when drivers perceive an immediate hazard when the roadway is less demanding. Roadway complexity can affect when drivers perceive closing and an immediate hazard when closing velocity is high. Application: Results can aid accident analysis cases and the design of driving automation systems by suggesting when a typical driver would respond.