Browsing by Subject "Stop signs"

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    Examining Optimal Sight Distances at Rural Intersections
    (Minnesota Department of Transportation., 2019-07) Morris, Nichole L.; Craig, Curtis M.; Achtemeier, Jacob D.
    Decisions made regarding driver sight distance at rural intersections are complex and require considerations for safety, efficiency, and environmental factors. Sight distance, cross-traffic velocity, and vehicle placements significantly affect driver judgment and behavior atthese intersections. A series of rural, two-lane thru-STOP simulated intersections with differing sight distances and traffic speeds were created and then validated by county and state engineers. Experimental data from 36 participants in a time-to-collision (TTC) intersection crossing judgment task and a rural highway thru-STOP intersection driving simulation task was analyzed to clarify the influence of rural thru-STOP intersection characteristics on driving performance and decision-making. Results demonstrated that longer sight distances of1,000 ft. and slower crossing speeds (i.e., 55 mph) were more accommodating for participants attempting to select gaps and cross from the minor road, corresponding with (1) lower mental workload, perceived risk, difficulty, and anxiousness, and (2) better performance in terms of estimated crash rate, and larger TTCs. Second, longer distances of 1,000 ft. appear to aid drivers’ responsiveness on the main road approaching an intersection, specifically when another driver on the minor road runs the stop sign. Minor road drivers positioned close tothe roadway at the stop sign, compared to standard stop bar placement, tended to help reduce the speed of main road drivers. Overall,results demonstrated a systematic improvement in the performance of both minor and major road drivers with the implementation of a1,000-foot sight distance at rural thru-STOP intersections.
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    Older Driver Support System Field Operational Test
    (Center for Transportation Studies, University of Minnesota, 2019-05) Libby, David A.; Morris, Nichole L.; Craig, Curtis M.
    Older drivers represent the highest injury and fatality rate per 100 million miles driven. The disproportionate fatality risk is linked to several known factors, ranging from failure to yield to cognitive and visual limitations to seatbelt use abstention to fragility. Through a series of focus groups, usability tests, and a controlled field test, a universally designed smartphone app (called RoadCoach) designed to reduce risky driving behaviors, such as speeding and hard braking, was previously found to have high usability among older drivers. The current research consisted of a field operational test of the app, which examined the baseline driving behavior (3 weeks) of 28 older drivers in Minnesota and Kansas, their driving behavior with RoadCoach feedback (6 weeks), and their driving behavior during a follow-up, no-feedback period (3 weeks). The results demonstrated marginal reductions in speeding behaviors while the app was functioning, but speed behaviors significantly increased after the feedback was discontinued compared to when it was active. Hard braking and stop sign violations were significantly reduced during feedback and post feedback. Finally, satisfaction and trust were high among users, with drivers reporting that the app helped improve their attention and focus on the task of driving.