Managing a fleet of trucks, heavy equipment, and other vehicles challenges road agencies large and small. While large agencies like MnDOT use software and specialized administrators to manage fleet management systems electronically, city and county agencies often do not. For some small agencies, fleet management may fall to a shop mechanic or two.
In a recent project from the Local Road Research Board’s Research Implementation Committee, researchers identified the fleet management needs of city and county agencies and reviewed various cost-effective tools that could help these agencies make fleet management decisions. They then developed a guidebook for local agencies that addresses the tools and methods needed to manage fleets effectively.
“The guidebook provides the benefits of fleet management, a comparison of various program features and attributes, and a contact for more information about each program,” says Guy Kohlnhofer, county engineer, Dodge County, and the project’s technical liaison.
The guidebook—Fleet Management Tools for Local Agencies (2017RIC01)—includes a matrix comparing the eight most widely used fleet management software tools among Minnesota agencies. Costs, equipment needs, tracking features, financial analysis applications, and other attributes are reviewed. Case studies of agencies that use spreadsheets, software, and specific fleet replacement strategies are also included.
Three approaches to fleet replacement planning are presented in the guide. “You may have a vehicle that has been driven 300,000 miles and needed little maintenance, while another vehicle has been driven 100,000 miles and has needed a lot of maintenance,” says Renae Kuehl, senior associate, SRF Consulting Group, Inc., one of the co-authors. “We provide three models to determine when you should replace each.”
One of the findings of the project is that spreadsheets are effective and widely available tools for managing fleets. They are easy to tailor to local needs and fleets, are well understood by most computer users, are part of most office software suites, and work well for small data sets. Disadvantages, however, include limitations in reporting features, easy corruptibility of data, and inconsistent data entry among users.
In contrast, fleet management software offers easy report generation; software linkage to fuel, financial, and other software systems or modules; secure and consistent data; and interagency shareability. However, these tools can be expensive. Software costs for managing fleets average almost $36 per vehicle, and annual support costs average about $18 per vehicle. Other disadvantages include the need for training and internet accessibility.
In a newly completed study, researchers found that stabilized full-depth reclamation has produced stronger roads for commercial loads in Minnesota, and the method shows promise for uses in rural agricultural areas. How much greater the strength gained with each stabilizing agent is better understood, though not conclusively.
What Was the Need?
With stabilized full-depth reclamation (SFDR), roadway builders pulverize and mix old (hot-mix or bituminous) pavement and on-site base aggregate with asphalt to create a new, thick layer of partially bound base over the remaining aggregate base of the former roadbed. The process eliminates the cost of hauling away old pavement and hauling in new, expensive aggregate, which is in limited supply.
Cracking and other damage in older pavements usually reflect through new asphalt and concrete overlays. SFDR roads, on the other hand, tend to avoid reflective cracking while meeting the increasing load demands of an aging roadway system in reduced funding environments.
To make a road stronger and more resistant to damage from heavy loads, most rehabilitation approaches require a thicker and wider roadway. SFDR may offer a way to build stronger roads without widening the road and without transporting old material from the road site and hauling new aggregate to the location.
In 2016, performance requirements of SFDR edged MnDOT and the Local Road Research Board (LRRB) closer to design standards for the technique by establishing testing, modeling and analytical methods for evaluating SFDR mixtures. Minnesota designers lack a method for giving SFDR designs structural design ratings to quantify how well the mixture will meet the needs of a new roadway. How much strength is gained by mixing in a stabilizer and laying the reclaimed road as a thick asphalt pavement base before adding the overlay remains unquantified.
What Was Our Goal?
Most replacement roadways need to be capable of bearing heavier commercial and agricultural loads than the original roads. Researchers sought to determine the structural value of SFDR in mixtures employing various stabilizing agents to help designers better accommodate rehabilitation and increased loading needs with SFDR.
“We’re really big on recycling, and we’ve been using SFDR and FDR for quite some time. We have increased confidence in SFDR. We just don’t know how high that confidence should be,” said Guy Kohlnhofer, County Engineer, Dodge County.
What Did We Do?
Researchers visited 19 Minnesota road sites to look at 24 pavement sections and surveyed pavement conditions, cracking and potholing for each segment. The team conducted stability testing with a dynamic cone penetrometer (DCP) at each section and removed three pavement cores from each for laboratory testing.
SFDR pavement can be difficult to properly core, and most specimens failed before laboratory testing. Researchers conducted tests of dynamic modulus in a way that simulated high and low vehicle speeds in the lab on the surviving 14 samples. The tests simulated the movement of wheels over pavement surface and examined the resiliency of the pavements in springing back from these rolling loads.
Based on these results, researchers plotted the laboratory test results in mathematical curves. They then analyzed their findings while referencing flexible pavement design procedures using the concept of granular equivalents (GEs) that is familiar to many avement designers in Minnesota. Finally, they estimated the structural difference between stabilized and unstabilized reclaimed materials and identified how the structural value varies with selected stabilization agents.
What Did We Learn?
Field surveys found roads performing well. Few of the pavement surfaces showed noticeable distress, and more recent surface coating treatments showed almost no distress over pavements in which distresses would quickly present themselves. DCP testing suggested that asphaltic stabilizers—asphalt, asphalt plus cement and modified asphalt—offered greater stiffness than fly ash and cement stabilization.
“We confirmed that what local engineers are doing has value, even if we weren’t able to generate more optimistic numbers,” said Charles Jahren, Professor, Iowa State University Department of Civil, Construction and Environmental Engineering.
Lab testing suggested that while SFDR mixtures offer less stiffness compared to regular hot-mix asphalt (HMA) layers, their stiffness diminishes less in comparison to HMA for slow-moving heavy loads like seasonal agricultural equipment. SFDR is worthy of additional consideration as a base layer, in such loading environments.
The most critical goal for this study was to quantify the granular equivalency of SFDR mixtures with various additives to standard aggregate bases. Foamed asphalt and engineered emulsion proved the most structurally beneficial stabilizers; SFDR mixtures with these materials offered GE values of 1.46 to 1.55, confirming the general MnDOT approach that SFDR can be used for a GE of 1.5. If road builders pulverize 4 inches of asphalt roadway with 4 inches of base aggregate and add foamed asphalt or emulsion stabilizer, the 8-inch asphalt base offers the strength of a 12-inch aggregate base. A pavement of HMA or portland cement concrete can follow to create a roadway section with greater strength than a roadway section with the same thickness of nonstabilized base.
SFDR performs well in the field and shows particular promise for use on rural roadways subject to seasonal, heavy agricultural loads. Researchers confirmed current GE inputs for SFDR and documented the performance of specific stabilizer options employed in Minnesota. Continued monitoring of SFDR road performance and additional testing and analysis would add more detail to design procedures and provide designers with greater confidence.
The Minnesota Department of Transportation (MnDOT) has 137 truck stations across the state. These stations house and allow maintenance of MnDOT highway equipment as well as provide office and work space for highway maintenance staff. Within 20 years, 80 of these stations will need to be replaced as they reach the end of their effective life spans. Researchers developed a geographic information system based modeling tool to determine the most effective locations for truck stations in the state. Using data from many sources, a new research study has determined that MnDOT could rebuild 123 stations, relocate 24 on land available to MnDOT and combine two. MnDOT would save millions of dollars using the location optimization alternatives over the 50-year life cycle of a typical truck station.
What Was the Need?
MnDOT operates 137 truck stations, 18 headquarter sites for maintenance operations and over 50 areas for materials delivery. Truck stations are used to house and maintain large highway equipment, and to provide office and work space for highway maintenance staff. Some stations also store materials.
The average life span of a truck station is 50 years. Within the next 20 years, 80 of MnDOT’s truck stations will need to be replaced. With costly capital replacement imminent, MnDOT has considered measures to optimize truck station locations within its eight state districts, including possibilities of reducing the size of some, increasing others, or combining the facilities of some state and local agencies into new partnerships. Determining the best effective locations for new truck stations could reduce costs for both state and local partners.
MnDOT needed a means of selecting and collecting the most appropriate data for an investigation into optimizing truck station locations. The agency also needed tools such as a computer model to analyze the data. These resources would allow MnDOT to determine the most time- and cost-effective locations for future truck stations.
What Was Our Goal?
The initial objective of this research project was to collect data about truck service areas, including the quantity of highway equipment and materials capacity, and the materials storage capacity of facilities. This information combined with service route data would allow MnDOT to optimize truck station locations by determining whether facilities should be closed, resized, combined or relocated, and whether other materials storage locations would be necessary. An economic benefit–cost analysis would compare alternatives.
What Did We Do?
To determine how other departments of transportation (DOTs) and related agencies have addressed choosing the best locations for facilities, researchers conducted a literature review that included reports from six state DOTs and Australia, Transportation Research Board publications and other research papers. In addition, they consulted the standards developed by MnDOT’s Truck Station Standards Committee.
Researchers also conducted surveys and interviews of both MnDOT and outside agency stakeholders.
With many data sets collected for each truck station site, researchers used a geographic information system (GIS) platform to solve a location-allocation problem and a multivehicle routing problem for the truck stations. The problems incorporated such factors as amount of equipment, equipment capacity, storage capacity, material demand for road segments and other information. Estimated costs of operation for each location alternative were compared to present costs of each truck station.
“Using real-world data, we built GIS models of maintenance operations to determine optimal truck station locations. With expected life spans of around 50 years, truck stations that are optimally located will reduce operating costs and save money for MnDOT and Minnesota taxpayers.” —William Holik, Assistant Research Engineer, Texas Transportation Institute
What Did We Learn?
The literature review showed that optimizations of facility locations may require a second level of sites, such as strategically placed materials storage depots. Some research also showed that both transportation and facility costs must be considered and that after a certain point, consolidation of stations could cost more as vehicles and staff were required to drive farther to reach them.
Reports of state DOT location optimization efforts were instructive. Iowa DOT noted the need to consider the slow highway speeds of snowplows. This was a critical element for researchers to include in their optimization models as it determines route travel times. Vermont Agency of Transportation highlighted the use of satellite materials depots. Generally, state DOT efforts were confined to small regional issues, unlike MnDOT’s statewide scope.
In interviews with MnDOT and local agency stakeholders, researchers learned about partnerships that already existed between MnDOT and city and county agencies. These partnerships primarily included the sharing of truck stations and sometimes of materials. These partnerships were included in the optimization development.
Researchers optimized the truck station location using a GIS optimization model and separate cost analyses. They developed alternatives for each truck station individually. Each alternative was then analyzed to determine costs and savings over a 50-year life cycle.
Finally, researchers determined which alternatives could be most effectively executed and their optimum order. They also developed an implementation plan for station relocation and replacement. This modeling was an iterative process: Each optimal location replaced the existing location and became the baseline against which the next station alternative was compared. The result was a comprehensive set of location possibilities for each MnDOT district with multiple alternatives for every truck station, including benefit–cost analyses. Researchers’ optimization solutions determined that 123 truck stations could be rebuilt on-site, 24 could be relocated on land available to MnDOT, and two could be combined.
“We successfully analyzed all of our truck station and loading locations, determined which were good candidates for potential relocation or consolidation, and developed a data-driven plan of action to save millions of dollars.” —Christopher Moates, Planning Director, MnDOT Building Services
MnDOT now has the information it needs to effectively implement cost-saving changes in future truck station planning and construction. The agency could use the researchers’ initial recommendations or further employ the GIS modeling tool to examine variations on the results of the project.
In a recently completed study, Minnesota researchers compare the performance and cost-benefit of the clean-and-seal versus rout-and-seal techniques for repairing asphalt pavement cracks.
Survey results, construction data and field evaluation of new repairs and their performance over two years gave rout-and-seal repairs a slight cost–benefit edge over clean-and-seal repairs. At an average performance index level, rout-and-seal offered about four years of service before failure; clean-and-seal offered about three years. The study also recommends rout-and-seal for use over clay and silt subgrades in most conditions. Decision trees were developed to help planners and repair crews select an appropriate repair method.
Preserving asphalt pavements so they maintain performance for decades requires a variety of repairs, including sealing cracks. Cracks allow water to seep into pavement structures, leading to damage from freeze-thaw expansion, stripping of the asphalt’s bond from the underlying structure, potholes and crack expansion.
For most crack repairs, road crews clean the crack and apply an asphaltic filler or sealant. MnDOT uses two approaches to repair cracks and create a smooth ride for passing vehicles: clean-and-seal and rout-and-seal. Both treatments force traffic closures.
With clean-and-seal, compressed air is used to remove debris from the crack before a sealant is applied. With rout-and-seal, a saw or router is used to grind a shallow trench or reservoir over the crack. The routed seam is then filled with an asphaltic sealant.
Rout-and-seal requires more time and, in many cases, slightly more sealant, making it more expensive than clean-and-seal. Some agencies favor clean-and-seal because it is less expensive, reduces the time crews are on the road and frees more time to maintain other cracks.
What Was Our Goal?
Researchers sought to determine which of the two repair methods offers the better value over time. If rout-and-seal delivers a longer-lasting repair, it may be more cost-effective than clean-and-seal in terms of life-cycle cost. The research team also needed to develop guidelines for selecting the most suitable repair method for the damaged pavement.
What Did We Do?
Researchers conducted a literature search to see how agencies around the country approach asphalt crack repair. The research team then surveyed Minnesota road agencies to see which repair method agencies prefer and how long repairs typically last.
To review performance of crack sealing, researchers evaluated the MnDOT construction logs of old repair sites and visited 11 new repair sites. These locations were revisited two, six, eight, 12 and 18 months following the repair. To calculate a performance index rating, researchers recorded data about site conditions that included sealant age, traffic level, subgrade soil type and crack sealing performance. Two sites were removed from the analysis when local crews applied chip seals to the pavements.
Investigators calculated performance index levels for each repair method at each site. They gathered cost data where available from bid-letting paperwork and determined life-cycle costs. Finally, the research team created decision trees that planners and maintenance crews can use to help select crack repair methods.
What Did We Learn?
“This study provided very useful information. The rout-and-seal has a better cost–benefit over the life of the pavement than the clean-and-seal, however, they are relatively close. Agencies will need to decide if they have the manpower or resources to perform one over the other.”
—Dan Knapek, Assistant County Engineer, Sherburne County Public Works
Limited research was identified that compared clean-and-seal and rout-and-seal treatments. Most studies of asphalt crack sealing compared unsealed and sealed pavement performance and have established that sealing does extend pavement life. None compared cost–benefits of the two methods.
Of 47 survey respondents, 68 percent use rout-and-seal and 32 percent use clean-and-seal. Responses identified no clear trends in life expectancies for the two methods, with predictions for service until failure falling predominantly in two to 10 years for clean-and-seal and two to 15 years for rout-and-seal. The most common criteria for choosing a method were crack or pavement condition (46 percent of respondents) and predetermined maintenance schedules (24 percent).
Analysis of MnDOT construction data found no statistically significant difference in life expectancies for the two methods, with service lives of 6.4 years for rout-and-seal and 6 years for clean-and-seal. A similarly slight advantage for service lives of both treatments was identified for low-volume roads over higher-volume roads.
After one year of service, the new seal sites delivered strong performance index figures. Short-term performance on rural roads was identical for the two methods. After the severe 2018-2019 winter, however, performance dropped significantly; spalling damage was frequently observed at rout-and-seal sites.
Analysis of old and new seal projects showed that at an average performance index level, rout-and-seal repairs last about four years and clean-and-seal about three. Life-cycle cost analysis found rout-and-seal slightly more effective. Because the difference is slight, factors such as treatment cost, life expectancy, ease of operation, traffic level and crew manager opinion may guide selection of sealing strategies.
Researchers developed two decision trees for selecting a repair method: one for pavement management and another for maintenance crews. Rout-and-seal is recommended for pavements over clay and silt subgrades.
Research that extends monitoring of the new crack seal sites for up to five years would provide useful data on performance and comparison of the effectiveness of the two methods.
“To help select an appropriate crack repair method, we developed two decision trees: a detailed one and a simple one with only three variables—crack size, traffic level and the number of times a crack has been sealed.”
—Manik Barman, Assistant Professor, University of Minnesota Duluth Department of Civil Engineering
The second phase is nearing completion for a project aimed at creating a Unified Permitting Process (UPP) for oversize/overweight (OSOW) vehicles in Minnesota. One outcome of this phase is a roadmap that will define steps for future phases, including statewide implementation.
Currently, haulers need to apply for OSOW permits with each individual roadway authority they will travel through. MnDOT, counties, townships, and cities all administer permits for their own roadways—so several different permit applications and processes can be required for a single haul.
“The streamlined permitting process is expected to increase efficiencies for the freight industry, which is good for our economy,” says Clark Moe, systems coordinator with MnDOT’s Operations Division, Office of Maintenance. “It will also enable more effective enforcement and help us preserve the quality of our road network.”
Through the UPP, agencies should have a better idea of what’s happening on their roads, says Rich Sanders, county engineer for Polk County. “Throughout the state, there are a lot of hauls we don’t even know about, let alone if they will use a restricted bridge or road.”
UPP Phases I and II
Phase I of the UPP project examined the feasibility of implementing a permitting platform. Completed in 2017, this phase included listening sessions across the state with the hauling industry, local agency engineers, law enforcement, state agencies, and MnDOT staff. Eighteen public and private entities collaborated to develop policies, processes, and plans for UPP technology. The final report concluded that a reference platform system for processing permit applications would be the best approach to explore.
Phase II was a proof-of-concept pilot project spanning St. Louis County, Polk County, the City of Duluth, and MnDOT Districts 1 and 2. The goal was to see if a permitting platform would work across jurisdictions connecting various permitting software and using multiple system processes. “The platform has to be usable in different ways and be able to channel payment back to MnDOT or a county or city,” Sanders says. “Phase II showed UPP could work.”
Phase II also underscored the complexity of the issues to come. “The vision is for haulers to enter their license data, and the required permit data would automatically populate the permit,” says Mitch Rasmussen, assistant commissioner with MnDOT State Aid. “But all kinds of software systems are now in use by local agencies, and MnDOT’s Office of Freight and Commercial Vehicle Operation is preparing to replace the two online systems it’s been using for decades. All the systems will need to talk to the unified platform. It will take time and money to build. The roadmap from Phase II can help us get there.”
Policy and fee differences are another challenge. To gather context and ideas, MnDOT recently completed a Transportation Research Synthesis to explore the practices of other state transportation agencies in setting, collecting, and distributing permit fees for heavy commercial OSOW vehicles (see related article). Another MnDOT study is under way to gather basic data about the permit fee policies of counties in Minnesota and throughout the country, including authority for the fees, cost range, and fee types.
When Polk County switched from a paper system to an electronic one, industry started applying for permits more consistently, Sanders says. With the paper system, five or six permit applications would be faxed in each year, and approval could take two days. But with its online system, the county received 201 applications between January 1 and October 26, 2018. “Approval might take us 30 seconds,” he notes.
UPP work to date has been funded by MnDOT and the Minnesota Local Road Research Board. Others involved include the Federal Highway Administration, state agencies (Minnesota Department of Public Safety, Driver and Vehicle Services, Minnesota State Patrol, Minnesota IT Services Geospatial Information Office), associations (Minnesota Association of Townships, Minnesota County Engineers Association, Associated General Contractors of America), private businesses (ProWest, SRF Consulting, Midstate Reclamation & Trucking, Tiller Corporation), and educational institutions (Upper Great Plains Transportation Institute, NDSU; Alexandria Technical & Community College). UPP Phases I & II were a unique collaborative public-private partnership to resolve a long-standing problem.
Next phases and final outcome
Moving forward, Phase III will begin development of the unified system using real data from multiple road authorities and databases in MnDOT Districts 1 and 2. Phase IV will take the platform beyond Districts 1 and 2 and roll out the system for testing statewide. Estimated completion is two to three years.
“Under current plans for the unified system, Minnesota road authorities will continue to set their own fees and may be able to connect their existing software, although some interoperable adaptations will be needed,” Moe says. “The new permitting process will focus on education for haulers, permitting agencies, and the public, as well as engineering decisions by agencies. This, in turn, will lead to increased enforcement effectiveness to help preserve road quality while boosting the economy.”
“Many decisions are still on tap,” Rasmussen adds. “There’s no decision yet of who’s going to own it and manage it, for example, or what fees might be recommended. There are a million moving parts, and many agencies and interests are involved. But we’re taking big strides toward our central goal: putting the right load on the right road, the right way, right away.”
Snowplow operators face harsh driving conditions and must also deal with fatigue and drowsiness. A recent multi-state research project identifies factors that cause driver fatigue in snowplow operators and recommends cost-effective solutions to help reduce it.
Clear Roads – a winter maintenance research initiative – surveyed 33 member states to gather data on snowplow operators’ experiences with fatigue. More than 2,000 snowplow operators from 23 Clear Roads states responded.
Nearly all the respondents (94 percent) reported feeling fatigue at some point while operating a snowplow during winter weather events. The majority of vehicle operators (59 percent) reported their shifts of 8 to 16 hours included both daytime and nighttime segments. Smaller proportions reported that they worked primarily during the day (22 percent) or primarily at night (18 percent).
Survey results also indicated that more experienced operators were more prone to fatigue, and those who worked shifts lasting longer than 16 hours reported significantly higher levels of fatigue.
Based on the results and analysis, researchers ranked the in-cab and external equipment that caused fatigue. The top four equipment-related sources of fatigue were bright interior lighting, standard windshield wipers, misplaced or insufficient auxiliary lighting, and old or uncomfortable seats.
Among the non-equipment-related sources of fatigue, the most commonly reported factor was silence (lack of music or talking), followed by length of shift, lack of sleep, and insufficient breaks.
Using the same ratings, researchers developed a list of recommended actions that can be implemented by agencies to decrease driver fatigue. The recommendations were based on a comparison of each solution’s costs (equipment costs and potential risk of adversely affecting fatigue) and benefits (effectiveness in reducing operator fatigue).
Among the researchers’ equipment-related recommendations, the most cost-effective called for adding:
A CD player or satellite radio to deliver music or speech, preventing short-term fatigue.
Dimmable interior lighting to reduce reflections on the windshield and windows, providing better visibility.
Dimmable warning lights to reduce back-reflected light from the warning lights, lowering visual distraction.
Snow deflectors to reduce the amount of snow blown on the windshield, providing better visibility.
Heated windshields to reduce snow and ice buildup on the windshield, providing better visibility.
Non-equipment solutions included encouraging adequate breaks, limiting shifts to 12 consecutive hours when feasible, developing a fatigue management policy, encouraging a healthy lifestyle, and designating dedicated rest locations for operators.
According to the report, both the equipment-related and non-equipment-related solutions provide easy and quick corrective actions that agencies can implement immediately to increase the health and safety of snowplow operators.
A new program piloted in western Minnesota to increase snow fence use among private landowners has been so successful that MnDOT is looking at rolling it out statewide.
The University of Minnesota’s Center for Integrated Natural Resource and Agricultural Management worked with MnDOT District 8 staff for more than a year to develop and test a snow fence outreach program that could be used by MnDOT district offices.
“After our training, we saw a 300 percent increase in the number of standing corn rows, and that was on the initiative of a few people in the maintenance group. We’d like to spread the training to other districts,” said Dean Current, Director, University of Minnesota Center for Integrated Natural Resource and Agricultural Management.
Living snow fences are natural vegetative barriers that trap blowing snow, piling it up before it reaches a road, waterway, farmstead or community. It could include leaving a few rows of corn or hay bales along the road side, or even temporary fencing.
MnDOT has about 3,700 sites that are suitable for snow fences. It estimates that if 40 percent of problematic sites had snow fences, the state could save $1.3 million per year in snow management costs. Despite the cost, safety and environmental benefits, private landowners have shown limited interest in the program. An effective outreach program was needed along with strategies for identifying MnDOT personnel who could promote the practice and recruit landowners to the program.
“If we can implement our blowing snow control program more consistently, we can help reduce crash severities, improve operational efficiencies due to snow and ice control measures, and improve the mobility of the public,” said Dan Gullickson, Snow Control Program Administrative Coordinator, MnDOT Office of Environmental Stewardship.
How Did We Do It?
In January 2016, investigators surveyed MnDOT District 8 employees to gauge their understanding of snow fences as well as their approach to working with landowners to implement blowing snow control measures. The investigators studied survey responses to assess awareness of and interest in promoting the use of snow fences and grading to reshape road environments for snow and erosion control. They also examined snow fence programs from around the country, identifying types of snow fences used and characteristics of programs that successfully recruit landowner participation.
Results from these efforts were used to design an outreach program that was presented to District 8 staff. In January 2017, investigators surveyed the staff to evaluate the training and redesign the program accordingly. Finally, investigators evaluated market values of various snow fence designs.
What Was the Impact?
Initial survey results identified two relevant types of district personnel: maintenance and program delivery staff. Maintenance staff involved in plowing and road care interact more with landowners than do program delivery staff, who design or redesign roadways and may be involved in acquiring land for snow fences. Though tailored for each group, all training described the MnDOT blowing snow control program and its implementation, the role of snow fence coordinators, operational benefits and awareness of how promotion of the program fits within the scope of an employee’s duties.
Keys to the success of snow fence programs around the country include strong relationships and direct communication with local landowners, funding, landowner interest in conservation and public safety, and observable benefits.
A follow-up survey showed marked improvement in staff knowledge of the program and willingness to promote it. Landowner participation grew from four sites to 15 in the year after training, due mostly to maintenance staff participation. Survey respondents suggested potential program improvements such as more program champions; outreach in spring and summer at community and farmer gatherings as well as at local and state fairs; and a clearer understanding of how program promotion fits within job responsibilities.
The market study demonstrated that nonliving snow fences, though the most expensive option for MnDOT, offer the largest benefit per acre. Landowners seem to prefer living snow fences and standing corn rows. MnDOT may wish to raise the annual payment for all living snow fences.
Considerations for MnDOT include implementing the training program in other districts, further defining central and district staff roles in snow fence promotion and implementation, incentivizing snow fence champions, developing more outreach material and maintaining relationships with landowners.
A new project currently under way aims to further expand these efforts.
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
The Minnesota-led Clear Roads winter maintenance research program has developed a set of training tools—two videos and two quick reference guides—to promote liquid roadway treatments and provide practical guidance for agencies implementing a liquid anti-icing/deicing program.
Many agencies use liquids such as salt brine as anti-icing treatments to prevent ice from forming on roadways. But the application of salt brine as a deicing treatment during or after a winter storm has been slower to catch on. When used in the right conditions, liquid deicing treatments are as effective as granular sodium chloride while using less salt, but liquid-only routes are used by only a minority of winter maintenance agencies. To get the word out about the benefits of using salt brine and other liquids as both anti-icing and deicing treatments, as well as provide practical information about liquid application procedures, Clear Roads initiated this project.
Need for Research
While there is a wide range of information available about the use of brine and other liquids for anti-icing and deicing, there was a need to offer clear, comprehensive guidance in a single resource and to provide training tools for implementation.
A 2010 Clear Roads project helped lay the groundwork for this effort by identifying the parameters for effective implementation of liquid-only plow routes. That project produced a quick reference guide that outlined the conditions when liquid deicing treatments are most effective and provided application rates and implementation recommendations. A follow-up study was needed to update this guidance and to develop tools to facilitate the implementation of liquid-only plow routes.
Objectives and Methodology
This project’s goal was to produce a set of training tools—two videos and two quick reference guides—explaining the benefits of liquid-only plow routes, outlining procedures for implementation, and addressing misinformation and misconceptions. The project had two objectives:
• Inform agency decision-makers and the general public about the benefits of liquid roadway treatments while dispelling common myths.
• Provide practical guidance for maintenance managers and plow operators, and for agencies looking to start a liquid-only program.
Researchers began by conducting a literature review of research and practices related to liquid-only plow routes. They then sent an online survey to agencies in 27 states to determine which agencies used liquid-only roadway treatments. The survey yielded 92 responses from state DOTs and county and municipal highway departments. Follow-up interviews with 14 survey respondents gathered information about types of roads where liquid-only routes are used, application rates and material usage, brine making and storage, cycle times and loading times, and public perception and environmental concerns.
Of the 92 survey respondents, 30 indicated that their agency had a liquid-only route. In general, these respondents reported that liquids are more effective than solid deicers in
the right circumstances. Based on the information gathered in the survey, interviews
and literature review, researchers created two videos:
A shorter video for agency decision-makers and the general public that discusses the benefits of liquid-only treatments while addressing common misconceptions (particularly misinformation about corrosion and salts in the environment).
A full-length video for practitioners that includes information from the short video as well as tips for starting a liquid-only program, discussion of equipment types, and recommended usage parameters and application rates.
To complement the videos, researchers created two 2-page quick reference guides—a Start-Up Reference Guide to help agencies gain buy-in for a liquid-only program and a Technical Reference Guide with more detailed usage parameters, application rates and general tips.
“To effectively get the word out about liquid-only road treatments, there was a need to put the right message in front of the right audience in a compelling way and to dispel myths and misconceptions. These guides and videos do just that,” said Project Co-Champion, Scott Lucas, Ohio Department of Transportation.
The videos and quick reference guides communicate key information about liquid-only routes, including:
Appropriate use: Liquids are especially effective during light snowfalls and at milder temperatures. Agencies also use liquids to loosen packed snow for plowing; during high winds when granular salt may blow off the roadway; and as anti-icing treatments before freezing rain.
Benefits: Liquid deicing treatments use less salt, which leads to cost savings and reduced environmental impact. Liquids begin to work immediately, and they stay on the roadway (no bounce or scatter).
Misconceptions: Liquid applications of salt brine do not cause more corrosion damage to vehicles than granular salt. Granular salt must dissolve into brine on the roadway in order to melt snow and ice, so either approach exposes vehicles to salt brine. Corrosion inhibitors can help; some studies show they are more effective with liquids than solids.
Benefits and Further Research
The videos give transportation agencies modern communication tools to help target specific audiences: The shorter video is more appropriate for social media distribution and sharing, while the longer video is more useful for agency staff training and cross-agency communication. Both the quick reference guides and the videos will help agencies garner support for liquid-only programs and provide practical guidance for
Researchers at the University of Minnesota Duluth (UMD) have developed a system that can use highway loop detector traffic flow and weather data to determine when road conditions have recovered from a snow event. Currently, the Minnesota Department of Transportation (MnDOT) relies on snowplow drivers to estimate when roads are back to normal. The new system aims to relieve drivers of that burden and increase overall fleet efficiency.
In two previous MnDOT-funded projects, UMD researchers looked at using data from loop detectors along with weather station data to develop an automated system that determines normal condition regain time (NCRT) based on changes in traffic flow patterns. The goal is to improve the accuracy of road condition estimates and give dispatchers a big-picture view of traffic flow.
“This is a shift to different criteria,” says John Bieniek, Metro District maintenance operations engineer at MnDOT. “The bare lane regain time is now based on judgments from plow operators on the highways and phone calls to dispatchers. We could use the new system to quickly direct trucks to harder-hit areas within and between stations as they are needed.”
The latest project, led by UMD civil engineering professor Eil Kwon, transformed a previously developed computer model into a user-friendly, integrated computer system. The system includes a data management module, a module for target detector station identification and speed recovery function, an NCRT estimation module, and a map- based user interface that allows dispatchers to generate the estimated NCRT for a specified area. Dispatchers and supervisors can also use the interface to assess traffic flow variations, assign plows, and generate reports for past snow events.
The team tested the new integrated system on data gathered from I-494 and I-694 during two snow events in 2015 and 2016. Results show the system was able to successfully generate NCRTs that met or exceeded the accuracy of estimates by maintenance personnel.
“The system developed in this research can provide consistent and objective estimates of the NCRT by utilizing the traffic flow data that are currently available from the existing detection systems in the metro area,” Kwon says.
Another goal of the project was determining a data-derived definition of normal traffic flow for snow-cleared roadways. As part of this effort, researchers found that traffic resumed free-flow conditions after roads were cleared, but always at a slightly slower speed than on normal, dry roads. Researchers then developed a process to determine the “wet-normal” free-flow speed at each detector station based on the traffic flow pattern during a given snow event.
So far, the system has only been used with data from past snow events and has not generated results in real time. Going forward, MnDOT plans to fund additional work that will incorporate big data tools to allow the system to operate in real time—as storms happen—to improve roadway snow operations.