Browsing by Subject "Speed control"

Now showing 1 - 3 of 3
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    Development of Freeway Operational Strategies with IRIS-in-Loop Simulation
    (Minnesota Department of Transportation, 2012-01) Kwon, Eil; Park, Chongmyung
    This research produced several important tools that are essential in managing and operating freeway corridors. First, a computer-based off-line process was developed to automatically estimate a set of traffic measures for a given freeway corridor using the historical detector data. Secondly, a prototype on-line estimation procedure was designed to calculate selected traffic measures in real time to assist operators in identifying abnormal traffic patterns. Third, the IRIS-in-loop simulation system was developed by linking IRIS, the freeway control system developed by MnDOT, to a microscopic simulation software through a data communication module, so that new operational strategies can be directly coded into IRIS and evaluated under the realistic simulation environment. Finally, two new freeway operational strategies, variable speed limit control and a density-based adaptive ramp metering strategy, were developed and evaluated with the IRSI-in-Loop simulation system.
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    Examining the Impact of ASE (Automated Speed Enforcement) in Work Zones on Driver Attention
    (Minnesota Department of Transportation, 2016-01) Morris, Nichole L.; Cooper, Jennifer L.; Ton, Alice; Plummer, John Paul; Easterlund, Peter
    Each year, there are over 500 fatal crashes in work zones in the U.S., with over 100 road construction workers killed on work sites (NSC, 2011; FARS, 2011). Speed and distraction are among the top contributing factors to work zone crashes (Garber & Zhao, 2002; Mountain, Hirst, & Maher, 2005; Wilson, Willis, Hendrikz, Le Brocque, & Bellamy, 2006). The purpose of this study was to investigate the impact of different types of speed enforcement methods on driver attention in work zones. The investigation not only examined enforcement methods currently used in Minnesota, but also examined how implementing automated speed enforcement (ASE), which is not currently used in Minnesota, may influence driver attention and behavior in simulated work zones. Overall, the results do not appear to support the hypothesis that ASE without dynamic speed display sign (DSDS) improves driver attention in work zones. There is some evidence, however, that drivers did heighten their visual attention in work zones with ASE+DSDS enforcement. Drivers fixated on the secondary task display less frequently in the ASE+DSDS condition compared to other enforcement types while they traveled in the downstream portion of the work zone. The largest effects of the study were found among the age groups, with younger and older drivers exceeding the speed limit most often and varying their speed slightly depending on the type of enforcement present. Middle-aged drivers exhibited the greatest speed control and tended to abide by the speed limit to the same extent regardless of the type of enforcement present.
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    In-Vehicle Dynamic Curve-Speed Warnings at High-Risk Rural Curves
    (Minnesota Department of Transportation, 2018-03) Davis, Brian; Morris, Nichole L.; Achtemeier, Jacob D.; Patzer, Brady
    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.