November 2022 Vol. 10, No. 8

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Work-Zone Traffic Control Seminar sessions in January and February

flagger on roadway directing traffic around construction zone

Minnesota LTAP is offering eight sessions of our Work-Zone Traffic Control Seminar in January and February. This three-hour seminar presents the latest in traffic-control devices and safety devices, including several unique approaches to traffic control and methods for reducing risk and liability. Details are available on the seminar web page.

This $35 workshop is scheduled from 9:00 a.m. to noon (registration begins at 8:30 a.m.) at these locations and dates:

  • St Cloud MnDOT, January 18
  • Rochester MnDOT, January 23
  • Duluth MnDOT, January 26
  • Empire Maintenance Facility, Rosemount, January 30
  • Detroit Lakes MnDOT, February 2
  • Shoreview MnDOT, February 6
  • St Cloud MnDOT, February 13
  • Shoreview MnDOT, February 16

Learn more:

CTAP training to get a facelift; other winter resources available

Snowplow shoveling snow on roadway

The Circuit Training and Assistance Program—the mobile arm of Minnesota LTAP—is undergoing a facelift after the recent retirement of our longtime trainer, Kathy Schaefer. During this transition, CTAP training is not available for scheduling, but other winter resources can help meet your needs.

CTAP is being retooled and enhanced to better serve local agencies by expanding on-site training opportunities across the state. We apologize for the inconvenience, and we hope you'll take advantage of our improved on-site training opportunities when they launch in 2023!

In the meantime, please check out the online training resources below or see our calendar of upcoming events to help meet your training needs.

Learn more:

Virtual Slurry Systems Workshop at low or no cost

cartoon of a paper with white x and text box above saying nomination

The International Slurry Surfacing Association (ISSA) holds its annual Slurry Systems Workshop each January in Las Vegas. In 2023, ISSA and the Federal Highway Administration (FHWA) will offer a virtual experience at low cost for anyone interested. They are also seeking nominees for invitation to take the training at no cost.

The in-person workshop involves 3.5 days of hands-on, classroom, and laboratory-like training. The virtual agenda is expected to be very similar, and the program may offer up to 12 PDHs.

The FHWA is offering an opportunity for up to 400 state and local DOT agency personnel to take advantage of this virtual training at no cost. If you wish to nominate a candidate, please email with your candidate’s name, email, agency, and job title (one candidate per agency). Please note that although the notification may not be available until January, you should send the information as soon as you can to hold a spot.

If you wish to enroll additional attendees, the cost for the virtual training is $50 per attendee. The program will be available for 30 days beginning in late January, allowing you to log in and out as many times as you need to review the training. ISSA will also offer several times where the presenters will be available for online chat to answer any questions that attendees may have after viewing the program.

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Idea hopper: What do you want to know?

hopper on the side of a building

Is there a question you’ve often wondered about but haven’t had time to look into? Are there topics you want to see in the MnLTAP electronic or print newsletters? If so, please let us know—we want to hear from you! Email us your ideas at, and we’ll add them to our Idea Hopper for future issues. You don’t need to write anything fancy or formal—think of us as your Alexa or Siri. For example, you could type “How do I apply for money from the new federal bills?” We’ll review your ideas and do our best to meet your needs. Thank you!

Potassium acetate for winter maintenance more toxic than expected

workers inspecting potassium buildup on a frozen lake

Researchers studied the environmental consequences of using a potassium acetate product as an alternative deicer and anti-icer. They found that the chemical could be more toxic than anticipated and should be used with caution.

Potassium acetate is less corrosive to steel and works at lower temperatures than road salt. Two research teams—one from the University of Minnesota and one from Iowa State University (ISU)—coordinated fieldwork, laboratory analyses, and modeling exercises to better understand its environmental consequences. The research was sponsored by the Minnesota Local Road Research Board and MnDOT.

ISU researchers found, unexpectedly, no observable biodegradation of potassium acetate during the study period, suggesting slow degradation in bodies of water. The University of Minnesota research team found that terrestrial and aquatic organisms were more sensitive to potassium acetate at lower levels than sodium chloride, primarily due to potassium.

The researchers concluded that extreme caution should be used when determining where and when to use a potassium acetate product as an alternative deicer. Its use may be limited to temperatures at which other deicers don’t function, and only in certain locations. Researchers prepared user guides to aid decision making.

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CTS annual report: Researchers shed light on pavements, safety, and more

graphic stating What We Do for You: Impact Reports 2022

How can we keep roadway pollutants out of our lakes and rivers? How did the pandemic affect telecommuting? These are just two of the issues studied by University of Minnesota transportation researchers in FY22. The 2022 Impacts Report from the Center for Transportation Studies shares highlights.

CTS identifies core transportation issues, convenes diverse groups of stakeholders, and helps inform policy and decision-making. In 123 leading-edge projects, U researchers shed light on nearly 100 critical topics: pavement mixes, bike lanes, rural intersections, and much more.

As part of the U’s land-grant mission, CTS also offers engagement and education programs. In FY22, nearly 1,200 participants attended CTS events, and 3,178 transportation professionals gained skills through customized training and technical assistance programs such as Minnesota LTAP.

Shared automated vehicles could have big impact on cities

automated vehicle with no passengers moving on an overpass

In an NSF-funded study, a team centered at the University of Minnesota examined the potential of shared automated vehicles (SAVs) to improve transportation and make it more equitable for all users. The team examined not only how SAV networks could work but also what the impacts on society might be. Cities could see benefits—for example, less pavement would mean less road runoff—but budgets could be hit hard.

The researchers examined considerations around the rollout and regularized use of a hypothetical SAV system in Minneapolis–St. Paul. They explored several scenarios with increasing levels of SAV adoption.

From their analysis, the researchers say SAV systems are feasible—and possibly very beneficial—in communities like the Twin Cities. They show how the technology could work and where revenues could come from. They show how SAVs could strengthen—not weaken—existing transit systems. And they illustrate what future streets could look like.

The report concludes with key recommendations for policymakers, planners, and other officials. Among the recommendations:

  • Revenue sources such as fuel taxes, parking fees, and fines will dry up. On the other hand, SAV providers that use public infrastructure and customer data could be a source of revenue. Communities should adjust budgets accordingly—and not sell the rights to mobility services cheaply.
  • Cities should start to plan how land that is currently devoted to parking and roads can be repurposed to address sustainability, equity, and housing affordability goals.
  • Policymakers should seek ways to use SAVs to connect people in low-density or poorly served areas to existing transit services.
  • The entire transportation system should be designed for diversity, serving all areas and different populations and user needs.
  • AVs will disrupt jobs for many people who drive for a living. Policymakers should mediate this disruption.
  • SAV development should include public engagement—and should not be planned and controlled solely by private interests.

Learn more:

Tool suite helps calculate ROI for resilience projects

picture of partially flooded roadway taken from centerline

Photo: Shutterstock

The USDOT Volpe Center has released the first public version of the Resilience and Disaster Recovery (RDR) Tool Suite (V. 2022.1). It enables transportation planners to calculate the return on investment (ROI) for transportation infrastructure resilience projects across a range of uncertain hazard scenarios.

The RDR Tool Suite is designed to help transportation agencies explore scenarios for transportation disruption and mitigation across a range of uncertain future hazards (e.g., floods, earthquakes) in the context of long-range transportation planning. It leverages standard travel demand modeling that is widely used by transportation agencies.

The tool allows agencies to incorporate the cost and benefits of resilience into the transportation planning decision-making process to make informed decisions on future infrastructure investments.

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Evaluation finds big benefits for rumble strips, high-friction surface treatment

Logo of Every Day Counts

In its Statewide Roadway Departure Action Plan, the Kentucky Transportation Cabinet (KYTC) recommended the installation of rumble strips and high-friction surface treatment (HFST), primarily on state roads with functional class “collector” or higher. The state evaluated these countermeasures and determined a benefit-cost ratio for centerline and edge-line rumble strips of up to 65:1 and a 44:1 ratio for HFST.

These findings led KYTC to systematically integrate rumble strips into the state’s resurfacing schedule. KYTC then developed a suite of safety performance functions used in network screenings for proven countermeasures, such as cable median barrier and HFST. This tailored network screening uses crash types and facility types that correlate with where these countermeasures are most effective (e.g., wet weather curve crashes for HFST). This allows KYTC to focus on locations with the most potential for safety improvement.

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Kentucky LTAP publishes road safety video series

screenshot of YouTube video dipicting Installation of Safety Edge

An 11-part video series on Road Safety was produced in partnership by the Kentucky LTAP, Federal Highway Administration, and Kentucky Transportation Cabinet. Topics include high-friction surface treatments, sign retroreflectivity, road safety assessments, and the Safety EdgeSM.