Browsing by Subject "Delays"

Now showing 1 - 4 of 4
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    Assessing the Impact of Pedestrian-Activated Crossing Systems
    (Minnesota Department of Transportation, 2020-05) Hourdos, John; Dirks, Peter; Lehrke, Derek; Parikh, Gordon; Davis, Gary; Cheong, Christopher
    Pedestrian-Activated Crossing (PAC) systems have been shown to have a generally positive impact on driver yield rates. However, there has been insufficient research on the effect PAC treatments have on pedestrian crash rates, and there is little guidance as to when and where each treatment should be used. This study estimates the effects of PACs on pedestrian crash rates using Monte Carlo simulation and examines the relationships between driver yield rates and a variety of treatments and site designs by conducting an observational study using video data from 34 locations. The simulation outcomes suggests that while the percentage of yielding drivers might be a useful indicator of pedestrian level of service, it is less helpful as safety surrogate. This could be because a driver?s yielding to a pedestrian, as observed in field studies, might not be the same behavior as a driver attempting to stop during a vehicle/pedestrian conflict. The observational study shows that the number of lanes to cross at a crossing is positively correlated with the rate at which pedestrians activate the system, but it is not correlated with the delay. Additionally, the study showed that the effect of PAC systems is most pronounced at sites with a higher number of movements conflicting with the crossing or poor visibility from upstream without signs warning drivers of an upcoming crosswalk.
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    Identifying Methods and Metrics for Evaluating Interagency Coordination in Traffic Incident Management
    (Center for Transportation Studies, University of Minnesota, 2009-05) Feyen, Robert G.; Eseonu, Chinweike I.
    One role of state-level Departments of Transportation (DOT) is traffic incident management (TIM): managing incidents that impact traffic flow on interstate highways and involving multiple agencies (e.g., police, fire). This study found DOTs collect basic TIM performance measures (e.g., lane clearance times), but many do not record additional measures, consistently review the collected data or analyze it unless needed to answer specific questions. Since performance evaluation of interagency coordination is one area of TIM in which little success has been attained (FHWA, 2003), process improvement methods from operations management may prove useful. To illustrate, interagency incident response for a disabled vehicle (no injuries or property damage) is modeled as a process in which appropriate resources (e.g., state police, tow) must coordinate to safely remove the vehicle and restore normal traffic flow. Completing these events requires the resources to perform specific functions, each taking more or less time depending on various factors (e.g., weather, time of day). Response time data can highlight geographic areas or process segments with highly variable event times, leading to investigation and recommendations to reduce variability and, ultimately, traffic delays. Based on this approach, recommendations are made for data collection and analysis of appropriate TIM performance measures.
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    Measure of Truck Delay and Reliability at the Corridor Level
    (Minnesota Department of Transportation, 2018-04) Liao, Chen-Fu
    Freight transportation provides a significant contribution to our nation’s economy. A reliable and accessible freight network enables business in the Twin Cities to be more competitive in the Upper Midwest region. Accurate and reliable freight data on freight activity is essential for freight planning, forecasting and decision making on infrastructure investment. A report entitled “Twin Cities Metropolitan Region Freight Study” published by MnDOT and the Metropolitan Council in 2013, suggested a need to understand where and when trucks are most affected by congestion. A framework for truck data collection and analysis was recommended to better understand the relationships between truck traffic and congestion in rush hours. Building upon our previous study to measure freight mobility and reliability along 38 key freight corridors in the Twin Cities Metropolitan Area (TCMA), this study leveraged our previous effort to implement the performance measures using the National Performance Measurement Research Dataset (NPMRDS) from the USDOT. The researcher team first worked with stakeholders to prioritize a list of key freight corridors with recurring congestion in peak periods in the TCMA. We used 24 months of NPMRDS data to measure travel time reliability and estimate truck delay at the corridor level and to identify system impediments during the peak hours. The objective is to use performance measures for assessing impact of truck congestions and identifying operational bottlenecks or physical constraints. Trucking activity nearby a congested area is examined to analyze traffic pattern and investigate possible causes of recurring congestions.
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    Using Truck GPS Data for Freight Performance Analysis in the Twin Cities Metro Area
    (Minnesota Department of Transportation Research Services & Library, 2014-03) Chen-Fu, Liao
    Building on our previous efforts to study freight mobility and reliability, a GPS-based data analysis methodology was developed to study the freight performance of heavy commercial trucks along 38 key freight corridors in the Twin Cities metropolitan area (TCMA). One year of truck GPS data collected in 2012 was obtained from American Transportation Research Institute (ATRI) to study freight mobility and reliability. Several performance measures, such as truck mobility, delay, and reliability index, were computed and analyzed by route, roadway segment, and time of day. For data quality and reliability verification, average truck speed and hourly volume percentage computed from the truck GPS data were validated with weigh-in-motion (WIM) and automatic traffic recorders (ATR) data at selected locations. The GPS based freight analysis methodology offers potential opportunities for freight planners and managers to generate reliable measures in a timely manner. The resulting performance measures indicate that these measures derived from truck GPS data can be used to support the USDOT performance measure initiative and support regional surface freight planner in identifying freight bottlenecks, infrastructure improvement needs, and operational strategies to promote efficient freight movement. FHWA recently announced the National Performance Measurement Research Data Set (NPMRDS) to support its Freight Performance Measurement (FPM). The NPMRDS includes probe vehicle based travel time data in every 5-minute interval. This report also explored the feasibility of using one month of NPMRDS data in Minnesota to compute freight mobility and speed variations along the National Highway System (NHS) during AM and PM peak periods.