The Minnesota-led Clear Roads winter maintenance program has profiled six state agencies’ experience with automatic vehicle location (AVL) and GPS in winter maintenance fleets to share best practices with other cold weather states. Strong support by these agencies drives robust use of the technologies for location tracking, asset monitoring and planning for future storms.
AVL and GPS have been widely embraced in winter maintenance operations by transportation agencies around the country. But tracking vehicle locations for operational and safety reasons only scratches the surface of these systems’ potential uses. Many agencies also use AVL/GPS to collect extensive data for planning, operations, safety and inventory tracking to improve efficiency and response strategies.
Need for Research
AVL and GPS have been used in winter maintenance operations for several years. While most agencies use AVL/GPS for tracking vehicle location, the technologies offer operational, safety, inventory and planning applications, as outlined in a 2016 Clear Roads synthesis report. How agencies actually employ these automatic data collection technologies has remained less well-known.
Objectives and Methodology
The goal of this project was to explore agencies’ experiences and best practices in planning, implementing and using AVL/GPS technologies for winter maintenance activities. The investigation began with a survey of state and selected metropolitan transportation agencies about their level of commitment to AVL/GPS implementation and the data the agencies collect, use and share.
Investigators worked closely with Clear Roads to identify levels of usage of the technologies. Then they selected six agencies that represented various commitment levels, interviewed staff from each agency and gathered relevant documents about agency use of AVL/GPS. Using the information obtained during the interviews, researchers prepared case studies of each agency and recommendations for other agencies to further implement and utilize the technologies.
Twenty-seven of the 38 agencies that responded to the survey reported using AVL/GPS to automatically collect winter maintenance data, while 36 of the 38 agencies indicated plans to add or expand use of the technologies in the future. Based on feedback from these agencies, researchers developed three levels of AVL/GPS use and categorized agencies according to the appropriate level.
Tier 1 agencies employ AVL/GPS for basic location tracking or monitoring. Utah DOT has mounted AVL/GPS behind the dashboard of every snowplow and incident maintenance truck (vehicles that assist stranded motorists on Utah’s roads and highways) in its fleet. The system connects with plow position sensors, tracks idling time and traveling speed, and reports plow locations on a publicly accessible website.
Tier 2 users add basic data collection, equipment integration and system reporting features to Tier 1 usage, often in concert with other technologies. Washington State DOT’s Tier 2 usage integrates AVL/GPS with spreader controllers, plow position sensors, and air and pavement temperature sensors in 80 percent of its fleet to track material use, road weather and operational analysis data. Michigan DOT integrates AVL/GPS with spreaders, plows and dashcams in 94 percent of its fleet to track vehicle location, vehicle diagnostics and material use, and to use for operational analysis and information sharing with the public.
Tier 3 agencies conduct complex data collection, integration and reporting activities with AVL/GPS as part of a suite of instruments and applications that collect and transmit data to users, the agency and, in some cases, the public. Colorado DOT (100 percent of its fleet), Nebraska DOT (33 percent) and Wisconsin DOT (53 percent) link AVL/GPS to data collectors, plows, spreader controllers, pavement and air temperature controllers, and other equipment. Each agency tracks vehicle location, material use, treatment recommendations, vehicle diagnostics and data for operational analysis, among other uses. Colorado and Wisconsin DOTs share data with a maintenance decision support system; Colorado DOT also shares information with the public.
Keys to success with AVL/GPS include obtaining full organizational and financial support from agency management, piloting the system with vendors and operators to identify objectives for use, providing operators with training that emphasizes the technologies’ operational and safety benefits, involving agency mechanics in installation, and using the system data for real-time adjustments to maintenance and resource-allocation strategies.
“The recommendations were very constructive— everything from planning and decision-making to how to best collect data and use it for performance measurement,” said Project Champion, Patti Caswell, Oregon Department of Transportation.
Benefits and Further Research
The final report offers information that will be useful to prospective and current adopters, describing best practices in AVL/GPS planning and implementation, procurement, installation, training, data collection and utilization, and operations and maintenance.
Future research may evaluate methods for integrating technologies from various manufacturers into a cohesive, operational system. Turnkey options remain limited, and integrating sensor, camera, data collection and GPS presents a number of technical challenges. Related study may evaluate communication terminology for uniform data
sharing between agencies. Follow-up research could also identify the costs and benefits of AVL/GPS to quantify the value of these technologies to users.
Connected vehicle technologies, which use roadside units to communicate with other roadside units and wirelessly with vehicles, offer potential applications for real-time data collection and sharing among plow operators and other stakeholders. The relative value and ability to implement such systems may warrant research and comparison to
This winter, MnDOT snowplow operators will test and document their experience using potassium acetate (KAc) during severely cold weather as a possible alternative to the commonly used deicing material sodium chloride.
MnDOT maintenance staff have used potassium acetate in the Duluth area as a deicing alternative in several locations (Bong Bridge, Blatnik Bridge, I-35 tunnels, and I-35 at Thompson Hill) with anecdotal success. Advantages of KAc include reducing chlorides runoff into water, a lower effective deicing temperature (approximately -20F) than salt or brine, and less corrosion to vehicles and public infrastructure.
KAc will be used on four plows at select locations in the MnDOT District 1 Duluth sub-area. Crews will document the effectiveness of KAc in removing snow and ice pack at temperatures of minus 15 to 20 degrees Fahrenheit and reducing the time it takes plows to achieve and maintain bare pavement during severely cold temperatures.
In addition to evaluating potassium acetate as an alternative de-icing chemical, researchers will develop application guidelines and material handling requirements.
Researchers from CTC & Associates will review the 2018 Transportation Research Syntheses, Field Usage of Alternative Deicers for Snow and Ice Control, and identify any additional information that is publicly available regarding national and international use of KAc as a de-icing and anti-icing agent. The focus will be on successful uses of the material (material concentration and application rates, weather conditions, timing, etc.) by highway agencies or transferable practices by airports.
MnDOT District 1 personnel will conduct field tests of KAc on selected plow routes during the winter of 2018-2019 and document key data about the amount of material used, locations, equipment, storm characteristics, pavement conditions and other elements. Researchers will assist MnDOT with the design of the field study, the creation of a data gathering tools to be used by plow drivers, monitoring of data quality during the study, analysis of data gathered during the winter season, and writing a report presenting the study conclusions.
Winter weather events have a regional and often national impact. “Storms never stop at the state line,” said Tom Peters, research and training engineer, MnDOT Maintenance Operations. “That’s why it’s so important for us to know about winter maintenance efforts around the country, and particularly at neighboring states with similar climates.”
MnDOT leads the Clear Roads Transportation Pooled Fund Project (clearroads.org), a national winter maintenance research consortium. In 2015, Clear Roads launched a national survey to collect and report the annual winter maintenance operations of state DOTs. The effort included nearly 50 data points related to equipment, materials and costs.
The results, which are available at clearroads.org/winter-maintenance-survey as a Microsoft Excel-based spreadsheet, are available at no cost for users to examine, analyze and parse as needed. Beyond the raw data, the spreadsheet includes calculated statistics and an interactive map for plotting key metrics.
The results quantified much of what was known only anecdotally and provided useful, actionable data. “Data trends by geographic region and over time let us make more informed operations decisions,” Peters said. “We can also draw on this information to communicate with management, elected officials and the public about how MnDOT’s winter operations fit in a national context.”
As the lead state, MnDOT commits significant administrative time and attention across the agency to Clear Roads. “It’s rewarding and satisfying to see such a useful product as one of the payoffs for all this effort,” Peters said.
Additional data collection for the 2015-2016 winter season is already complete. Look for an update to the online database later this year.
Research in Progress
Clear Roads has nearly a dozen research projects in progress, including:
Standards and Guidance for Using Sensor Technology to Assess Winter Road Conditions
Emergency Operations Methodology for Extreme Winter Storm Events
Weather Event Reconstruction and Analysis Tool
Training Video for the Implementation of Liquid-Only Plow Routes
What is Clear Roads?
Clear Roads is a 33-member pooled fund program dedicated to winter road maintenance research. Led by MnDOT, Clear Roads projects evaluate winter maintenance materials, equipment and methods; develop specifications and recommendations; study and promote innovative techniques and technologies; and develop field guides and training curricula. Learn more at clearroads.org.
Even naturally derived products like corn syrup and beet juice can impact the environment when applied to salt mixtures for winter roadways.
A wide range of products, including the ones mentioned above, are added to deicing mixes to limit the amount of salt needed for Minnesota roads each winter. However, although information is available about the corrosive properties of various deicing chemicals, less is known about the toxicity of these compounds, especially to the aquatic environment.
Thanks to a recently completed project sponsored by the Clear Roads Pooled Fund, MnDOT winter maintenance personnel will better understand the relative toxicity of eight common deicing agents, which also include non-organics like Magnesium Chloride, Calcium Chloride and Potassium Acetate.
“Because the state has been trying a lot of different alternative chemicals, we wanted to get a better handle on the environmental impacts,” said MnDOT engineer Tom Peters, the technical liaison for the 26-member, Minnesota-led pooled fund for winter maintenance research.
In January, researchers plan to release a concise summary of the toxicity rankings to help winter highway maintenance managers consider both expected levels of service and potential harm to the environment when selecting a deicer.
Minnesota is the lead state for the Clear Roads Pooled Fund, which conducts rigorous testing of winter maintenance materials, equipment and techniques. Other recent and upcoming research (see our Technical Summary on the program) includes a winter maintenance cost-benefit analysis toolkit, snow removal techniques at extreme temperatures and environmental factors that can cause fatigue in snowplow operators.
You can learn more about Clear Roads via the project’s e-newsletter.