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Work zones present an increased risk to drivers and the work crew. To mitigate these risks; this study investigated the potential effects of in-vehicle messages to communicate work zone events to the driver. The researchers conducted literature reviews on risks imposed by work zones; along with design guidelines for any in-vehicle messaging system. The researchers then conducted a work zone safety survey to illustrate driver attitudes in Minnesota toward work zones; along with smartphone use and in-vehicle messages through smartphones. The survey found that a significant number of drivers make use of smartphones in the automobile; and they placed these smartphones in various locations throughout the vehicle. The survey was followed by a driving simulation study that tested drivers in two different types of work zones. Participants drove through these work zones three times; each with different messaging interfaces to communicate hazardous events to the driver. The interfaces included a roadside; portable changeable message sign; a smartphone presenting only auditory messages; and a smartphone presenting audio-visual messages. There was better driving performance on key metrics including speed deviation and lane deviation for the in-vehicle message conditions relative to the roadside signs. Furthermore; drivers reported significantly less mental workload and better usability; work zone event recall; and eye gaze behavior for the in-vehicle conditions relative to the roadside sign condition.

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 at these 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 to the 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.

Lane-departure crashes at horizontal curves represent a significant portion of fatal crashes on rural Minnesota roads. Because of this; solutions are needed to aid drivers in identifying upcoming curves and inform them of a safe speed at which they should navigate the curve. One method for achieving this that avoids costly infrastructure-based methods is to use in-vehicle technology to display dynamic curve-speed warnings to the driver. Such a system would consist of a device located in the vehicle capable of providing a visual and auditory warning to the driver when approaching a potentially hazardous curve at an unsafe speed. This project seeks to determine the feasibility of in-vehicle dynamic curve-speed warnings as deployed on a smartphone app. The system was designed to maximize safety and efficacy to ensure that system warnings are appropriate; timely; and non-distracting to the driver. The developed system was designed and implemented based on the results of a literature survey and a usability study. The developed system was evaluated by 24 Minnesota drivers in a controlled pilot study at the Minnesota Highway Safety and Research Center in St. Cloud; Minnesota. The results of the pilot study showed that; overall; the pilot study participants liked the system and found it useful. Analysis of quantitative driver behavior metrics showed that when receiving appropriately placed warnings; drivers navigated horizontal curves 8-10% slower than when not using the system. These findings show that such a curve-speed warning system would be useful; effective; and safe for Minnesota drivers.