Browsing by Subject "Winter maintenance"

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Adaptive Management to Improve De-Icing Operations
(Minnesota Department of Transportation, 2021-03) Baker, Lawrence A.; Wilson, Bruce; Klimbal, Doug; Furuta, Dan; Friese, Melissa; Bierman, Jacob
Road de-icing is a major cause of chloride impairment in Minnesota's urban waters. The goal of our study was to develop an adaptive management (AM) strategy to reduce chloride impacts caused by de-icing operations. The AM process was informed by our analysis of chloride movement in a residential watershed, providing feedback to the street department of our collaborator, the City of Edina. A key finding was that most the chloride movement occurred during a small number of events, with half of annual chloride movement occurring in less than 50 hours during each of the two years of study. This observation means that targeting these events might be a more effective way to reduce chloride impacts than more generalized approaches. We also found that a significant amount of chloride added to streets during de-icing accumulated in roadside snow piles, likely contributing to groundwater contamination. To address this concern, we developed a spreadsheet tool to estimate steady-state (long-term) chloride concentrations in groundwater. Scenario analyses indicated that groundwater chloride levels in highly urbanized watersheds would eventually exceed water quality standards. We developed a second model, intended for use by urban planners, to estimate the impact of changing the percentage of salted impervious surface on chloride movement in re-developed watersheds.
Deployment of a Snowplow Driver-Assist System
(Minnesota Department of Transportation, 2023-06) Davis, Brian; Schwieters, Katelyn; Morris, Nichole L.; Donath, Max
Snowplow operators are often tasked with clearing snow from roadways under challenging conditions. One such situation is low visibility due to falling or blowing snow that makes it difficult to navigate, stay centered in the lane, and identify upcoming hazards. To support snowplow operators working in these conditions, University of Minnesota researchers developed a snowplow driver-assist system that provides the operator with visual and auditory information that is suitable for low-visibility situations. A lane-guidance system uses high-accuracy Global Navigation Satellite System (GNSS) and maps of the roadway to provide information to drivers about their lateral positions. A forward-obstacle-detection system uses forward-facing radar to detect potential hazards in the roadway. The design of the system, and in particular its interface, is guided by extensive user testing to ensure the system is easy to understand, easy to use, and well liked among its users. The system was deployed in two phases over the 2020-2021 and 2021-2022 winter seasons. In total, nine systems were deployed on snowplows across Minnesota, four in the first winter season and an additional five in the second. Participating truck stations represented all eight MnDOT districts as well as Dakota County. Over the course of the deployment, additional user feedback was collected to identify system strengths and areas for improvement. The system was found to be a cost-effective addition to snowplows that increase driver safety, reduce plow downtime, and increase driver efficacy for plowing operations, thus providing support to operators working in demanding, low-visibility conditions.
Estimation of Winter Snow Operation Performance Measures with Traffic Data
(Minnesota Department of Transportation, 2012-12) Kwon, Eil; Hong, Seongah; Kim, Soobok; Jeon, Soobin
This research produced an automatic process to identify the road condition recovered times during snow events from the traffic-flow data. For this study, the traffic data from the past snow events were analyzed and the speed variation patterns indicating the road condition recovery states during the recovery periods were identified. The prototype process developed in this study finds the speed change point indicating the recovery of the road condition by analyzing the speed variations for a given location. The process was then applied to a set of the past snow events and the estimated recovered times were compared with the reported lane-regain time data.
Estimation of Winter Snow Operation Performance Measures with Traffic-Flow Data, Phase 2
(Minnesota Department of Transportation, 2015-08) Kwon, Eil; Park, Chongmyung; Hong, Seongah; Jeon, Soobin
An automatic process is developed to determine the normal condition regain time (NCRT) using the traffic flow data for a given snow event. To reflect the different traffic flow behavior during day and night time periods, two types of the normal conditions are defined for each detector station. The normal condition for day time is defined with the average speed-density patterns under dry weather conditions, while the time-dependent average speed patterns are used for representing night time periods. In particular, the speed-density functions for the speed recovery and reduction periods were calibrated separately for a given location to address the well-known traffic hysteresis phenomenon. The resulting NCRT estimation process determines the NCRT as the time when the speed level on a given snow day recovers to the target level of the normal recovery speed at the corresponding density for the day time periods. The sample application results with the snow routes in Twin Cities, Minnesota, show the promising possibilities for the estimated NCRT values to be used as the reliable operational measures, which could address the subjectivity and inconsistency issues associated with the current bare-lane regain times determined through visual inspections.
Friction Measurement System for Hennepin County
(Intelligent Transportation Systems Institute, Center for Transportation Studies, University of Minnesota, 2013-01) Alexander, Lee; Rajamani, Rajesh
A friction measurement system was developed for Hennepin County and installed on a snowplow in their winter road maintenance fleet. The major components of the developed system were a special instrumented wheel, a pneumatic pressure-controlled cylinder, force-measurement load cell and accelerometers, and a data processing micro-processor and LCD display. The project plan initially included interfacing the friction measurement system with an applicator and automatic control of the applicator on detection of a low tire-road friction coefficient on the road. However, due to concerns from Hennepin County about interfacing with the applicator electronics and its potential influence on normal operation of the Force America applicator, the friction coefficient was estimated in real-time and just displayed for the snowplow operator. It was not used for real-time control of the applicator. The stand-alone hardware developed in this project is being used as a platform for development and installation of friction measurement systems on two snowplows in Polk County during the 2012-2013 winter. The Polk County installation is being funded by the Minnesota Local Road Research Board.
Guidance for Separated/Buffered Bike Lanes with Delineators
(Minnesota Department of Transportation, 2021-05) Hourdos, John; Duhn, Melissa; Dirks, Peter; Lindsey, Greg
Separated bicycle lanes (SBLs) are bicycle facilities that employ both paint and a vertical element as a buffer between vehicle traffic and bicycle traffic. In recent years, the installation of SBLs has increased in the U.S. as planners and engineers seek to reduce crash risk, increase safety and foster demand. In turn, public demand for these facilities has continued to grow. This project conducted a thorough literature search to identify knowledge gaps and aspects of design not addressed in depth in existing guides. In collaboration with the Local Road Research Board and MnDOT, the study identified which design elements were of the greatest local interest or missing from the guidance altogether. The identified subject areas were explored with the help of three major knowledge gathering approaches: interviews of industry professionals from local agencies currently operating SBLs, interviews with leading bicycle advocates representing the local cycling community, and an ambitious and lengthy online survey of people who cycle in Minnesota. As noted by several existing guidance documents and corroborated by the information collected and analyzed in this project, the SBL is one of the highest quality bikeway facilities available. This report adds to the existing guidance regarding the planning and operation of SBLs by refining the discussion and taking into account individual aspects of separate design elements and their implementation alternatives, as well as their influence and limitations on maintenance needs, especially in winter. The guidance identifies multiple considerations for each of the selected structural elements and maintenance considerations to inform the choices made during the design process.
Influence of Autonomous and Partially Autonomous Vehicles on Minnesota Roads
(Minnesota Department of Transportation, 2023-05) Espindola, Andre; Alexander, Lee; Rajamani, Rajesh
This project focuses on experimental tests of the performance characteristics of autonomous vehicles (AVs) on highways and local roads in Minnesota. The project provides detailed data characterizing AV performance, which in turn can be used to inform the transportation community on implications for infrastructure maintenance, winter road maintenance, work zone guidelines, safety, and traffic capacity. The experimental work presented here makes use of a new autonomous vehicle purchased by the Center for Transportation Studies at the University of Minnesota. The key aspects of the autonomous functions of the vehicle studied in this project include winter performance and implications for road maintenance, characterization of the driving performance of the AV and its likely influence on safety, traffic flow and fuel economy, and the ability of the AV to handle work zones and the implications on changes needed to the guidelines for work zones. The project documents the major challenges and obstacles ahead in the way of true autonomy on Minnesota roads, but also outlines further areas for research with which it will be possible to facilitate the improvement of the capabilities of autonomous vehicles in Minnesota in the future.
Optimal Workforce Planning and Shift Scheduling for Snow and Ice Removal
(Minnesota Department of Transportation Research Services Section, 2010-12) Gupta, Diwakar; Tokar-Erdemir, Elif; Kuchera, Dustin; Mannava, Arun Kumar; Xiong, Wei
Shrinking budgets and high equipment, fuel, and labor costs have raised the importance of workforce planning and efficient deployment of available workforce for county-level winter maintenance operations. This project focused on developing methodologies for the estimation workforce requirements, and economic evaluation of the impact of using contract employees, split shifts and staggered shifts. In order to achieve these goals, a fundamental question that needed to be addressed was the determination of the amount of work induced by different types of storms that occur in Saint Louis County. Researchers obtained relevant storm data from a variety of weather reporting sources and extracted parameters relevant for determining plow speeds and sand/salt consumption. These parameters were used to determine optimal workforce deployment strategies that balance overtime and delay costs, which in turn provided estimates of the amount of plowing time needed for the goal of clearing roads within 24 hours after the end of snow fall. Plowing time calculations were subject to rules concerning when call outs can occur during off-shift hours. Plow time estimates were subsequently used to develop efficient algorithms to calculate workforce requirements.
Permeable Pavement for Road Salt Reduction
(Minnesota Department of Transportation, 2020-06) Erickson, Andrew J.; Gulliver, John S.; Herb, William R.; Janke, Benjamin D.; Nguyen, Nam K.
Road salt and particularly sodium chloride is used for de-icing roadways during winter months in cold climates but can have a negative impact on the environment. This report describes research that investigated the use of permeable pavements that are not treated with road salt as an alternative to impermeable pavement surfaces that are treated with road salt. Various methods were used to quantify the snow and ice cover on impermeable and permeable pavements under near-identical but various environmental conditions. It must be noted, however, that impermeable pavements including the ones in this study are typically managed with road salt while permeable pavements are not. However, the following conclusions can be drawn from previous research and data collected during this project: 1) permeable pavements and the porous subbase beneath them function as thermal insulators, preventing heat transfer from the surface to below and vice versa; 2) permeable pavements that are clogged due to sediment accumulation or collapsed pores provide no benefit compared to impermeable pavement; 3) more sites with impermeable pavement had more friction than sites with permeable pavement; 4) more sites with impermeable pavement had less snow and/or ice cover than sites with permeable pavements; and 5) more sites with impermeable pavement had pooled water than sites with permeable pavements. This demonstrates the primary winter benefit of permeable pavements: meltwater can infiltrate through permeable pavements and prevent refreezing. Refreezing of meltwater on impermeable pavements creates dangerously slippery conditions which can be avoided with functional permeable pavements.
Reducing Winter Maintenance Equipment Fuel Consumption Using Advanced Vehicle Data Analytics
(Minnesota Department of Transportation, 2023-01) Northrop, William; Challa, Dinesh Reddy; Eagon, Matthew; Wringa, Peter
This project analyzes the impact that idling and snowfall have on the fuel consumed by MnDOT's snowplow fleet, with the underlying objective to determine and advise MnDOT on ways to reduce fuel usage of the fleet using vehicle telematics data. This is a significant problem to solve as fuel use reduction contributes to MnDOT?s sustainability goals of achieving a 30% reduction in fossil fuel use and greenhouse gas (GHG) emissions from 2005 levels by 2025. Furthermore, rising fuel costs are a future cause for concern due to an increase in business operational costs that increases the burden on taxpayers to keep roads safe in winter. This problem is challenging because existing on-board diagnostics (OBD) data do not contain mass information for the trucks' fuel use, which can fluctuate significantly when they are applying deicing substances to the road. Taking a mean value for the vehicle mass, we observe a clear positive correlation between snowfall and average fuel use. For days with snowfall totaling 4 inches or more, fuel use rises more than 25% on average compared to days without snowfall. In addition, the results from the idling analysis indicate that the idling time associated with the fleet is about 23% of total recorded hours and constitutes about 4.3% of the total fuel used. Daily idling activity reports containing information about idling events and fuel economy are generated for the sampled vehicles and shared with MnDOT.

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