All posts by Stefanie Toftey

research, Traffic and Safety

New Project: Can Enhancing Color on Dynamic Message Signs Improve Clarity and Safety?

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The majority of MnDOT’s dynamic message signs (DMS) are equipped to produce full color/full matrix messaging. Current signage regulations refer to retroreflective colors for static signs, but MnDOT aims to extend and modify existing standards and guidelines by exploring differences between static signs and DMS.

To receive email updates about this project, visit MnDOT’s Office of Research & Innovation to subscribe.

This research will systematically explore and optimize the use of different colors and color-coding schemes in DMSs to resemble the retro-reflectivity of static signs and examine how legibility, visibility, and effectiveness can be improved. Optimizing DMS colors to mimic retroreflective static sign colors and adapting them to myriad environmental conditions, MnDOT can realize reduced driver distractions, improved information comprehension, and increased safety. The project will also support improved decision-making processes by providing evidence-based guidance for future standards and practices for MnDOT beyond.

A pilot study will be conducted to assess the recommended color settings against benchmark real-world conditions. Empirical data on the new configurations will measure their performance, confirm their effectiveness and identify any adjustments required prior to broader implementation.

“Not all color is created equal! As illustrated in the three graphics below, federal standards for reflective sheeting and striping, NEMA standards for colors, and the triangle of visible light LED lights can produce do not correspond,” said Terry Haukom, senior engineer with MnDOT’s Regional Transportation Management Center. “This variance has caused the signage industry to display colors that meet federal standards but do not look correct to the human eye. In addition to exploring this incongruity, our research is focused on understanding and comparing what typical travelers understand and expect when viewing traffic information on the web, and whether the travel time numbers displayed on our signs can give drivers a better understanding of the travel time to the listed destination if it was displayed with a color scheme that leveraged web-based maps.”

The Objectives:

  1. Standardize the emitted colors from MnDOT’s DMS according to NEMA TS4 and MUTCD specifications, ensuring they match the retroreflected colors of static signs and align with current LED capabilities
  2. Document the public’s perception of optimum color if different from standards based on human factors feedback
  3. Document the public’s perception of dark pixel around graphics on emitted colors on DMS
  4. Research and document the public’s perception of emitted colors on DMS compared to static sign messages, and explore the incorporation of web-based travel time map colors to enhance visibility and clarity, especially with colors like amber

Project Details:

Details of the research study work plan and timeline are subject to change.

To receive email updates about this project, visit MnDOT’s Office of Research & Innovation to subscribe.

Policy and Planning, research

New Project: Understanding How Parking Space Requirements Affect Vehicle Miles Traveled

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Minimum parking requirements were established in the mid-20th century to mitigate increased motor vehicle congestion but have the potential to contribute to urban sprawl, hinder development, and curb incentives for drivers to choose alternative travel modes. Eliminating or reducing these requirements can help remove excess parking supply, increase alternative modes such as transit ridership, reduce vehicle miles traveled (VMT), and enhance economic productivity. Decreasing VMTs directly mitigates emissions by reducing car travel distances and many VMT reduction strategies hold additional benefits such as increasing accessibility and reducing traffic congestion.

To receive email updates about this project, visit MnDOT’s Office of Research & Innovation to subscribe.

VMT reduction also plays a significant role in Minnesota’s efforts to reduce greenhouse gas emissions from the transportation sector. New legislation passed in 2023 requires reducing VMT up to 20% per capita by 2050. The impacts of parking space requirements or long-term benefits and challenges associated with modifying or removing these requirements have not been studied in Minnesota. This project will investigate, document, and advance the understanding of minimum parking requirements in Minnesota and the region and their impact on VMT reduction.

Researchers aim to establish recommended values based on differing types of land use and community context, e.g., urban, suburban, and rural within Minnesota. Specifically, this project will examine the long-term benefits and challenges presented by reducing and/or removing currently established parking space requirements with new or redevelopment projects, and opportunities for parking space reallocation with existing uses.

“This research aims to fill a critical knowledge gap, will modernize minimum parking requirements reduce vehicle miles traveled, and provide communities with more flexible land‑use options,” said Mark Vizecky, state aid operations engineer, State Aid for Local Transportation at MnDOT.

The Objectives:

  1. Perform literature reviews of historical and current practices, policy and requirements regarding parking space requirements in Minnesota and the Upper Midwest and of current best practices regarding parking space requirements and the impact parking has on land use and travel behavior.
  2. Interview local agencies and the League of Minnesota Cities to gain insight into current parking space practices, policies, and requirements across Minnesota.
  3. Conduct an online survey of business stakeholders to assess the potential economic impacts of parking policy changes regarding customer behavior, business density, operating costs, opportunity cost and sunk cost, and accessibility.
  4. Conduct a travel behavior and mode choice survey using a diverse group of daily commuters from Minnesota’s urban, suburban, and rural communities to understand the influence of parking policies on traveler behavior.
  5. Analyze survey responses using discrete choice modeling to develop utility equations for different parking requirements, which will help predict mode shifts and associated VMT reductions.
  6. Utilize travel demand model data from eight metropolitan planning organizations in Minnesota to assess how changes in parking requirements could impact VMT reduction.
  7. Analyze the sensitivity and data requirements for a parking space requirement that will be effective for local use and develop a toolkit for local municipalities to assess parking needs and the economic impacts of parking policies in local communities.

Project Details

  • Start Date: 06/02/2025
  • Estimated Completion Date: 04/30/2027
  • Funding: Local Road Research Board (LRRB)
  • Principal Investigator: Kakan Dey
  • Co-Principal Investigators: Subasish Das, Ali Zockaie
  • Technical Liaison: Mark Vizecky

Details of the research study work plan and timeline are subject to change.

To receive email updates about this project, visit MnDOT’s Office of Research & Innovation to subscribe.

Materials and Construction, research

New Project: Using Satellite Technology to Monitor Ground Deformations Adjacent to Roads

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Geohazards generated by ground movements (e.g., landslides, subsidence, sink holes, etc.) cause substantial damage and interruptions to Minnesota’s highway network. Reactive monitoring approaches and borehole-based instrument sensing both have limited spatial coverage and are limited to sites already known to be in distress. This research explores the establishment of continuous satellite-based InSAR monitoring of ground deformations adjacent to roads on a broad geographic scale that would enable detection of pending hazards before they develop into large failures.

To receive email updates about this project, visit MnDOT’s Office of Research & Innovation to subscribe.

This warning system will combine data from high spatial resolution InSAR measurements, optical remote sensing data, and deep learning algorithms to automatically detect and continuously monitor deformations across large spatial regions. The research team will create MnDOT training modules to demonstrate the utility of the deformation data and automated warning system.

InSAR monitoring is expected to improve the safety and reliability of Minnesota’s transportation system and reduce costs and delays associated with emergency repairs. It would also support the state’s geotechnical asset management program by assessing the feasibility of InSAR for tracking performance of geotechnical assets (e.g. retaining walls, slopes, pavement foundations, etc.).

“This research project will help us determine if InSAR technology is ready for prime time for transportation agencies as a remote sensing tool to track performance of assets,“ said Raul Velasquez, geomechanics research & deployment engineer at MnDOT’s Office of Materials and Road Research.

The Objectives:

  1. Develop an automated warning system that can alert MnDOT staff of areas where abnormal ground deformation (e.g., landslides, subsidence, and sinkholes) is occurring along Minnesota interstate highways, allowing them to proactively intervene.
  2. Assist MnDOT in continuing to build its geotechnical asset management program by assessing the feasibility of InSAR for tracking performance of geotechnical assets such as retaining walls, slopes, and pavement foundations.

Project Details

Details of the research study work plan and timeline are subject to change.

To receive email updates about this project, visit MnDOT’s Office of Research & Innovation to subscribe.

Environment, research

New Project: Engineering Post-Construction Soil Composition to Support Resilient Stormwater Management

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Post-construction soils can produce much higher stormwater runoff rates than pre-construction or typical vegetated soils. Poor soil conditions can hinder the establishment of vegetation and carry large volumes of runoff, sediment, and nutrient loads to local waters. Organic soil amendments (composts) may support post-construction vegetative growth by boosting soil structure, nutrient availability, and water holding capacity.

To receive email updates about this project, visit MnDOT’s Office of Research & Innovation to subscribe.

This research aims to define targeted pre-construction soil health baselines, determine optimized design and field implementation inputs that return soils to baseline health indices using organic amendments, and identify how these inputs can benefit transportation requirements and resilient stormwater treatment.

The results may facilitate the quantification of benefits provided through soil health restoration and the development of implementable guidance for roadside soil health restoration techniques.

“This research project will help us understand how implementing soil health practices can improve the performance of roadside vegetation establishment resulting in MnDOT being able to close out construction contracts and stormwater permits sooner,” said Warren Tuel, Natural Resources Program Coordinator with MnDOT’s Office of Environmental Stewardship. “There are also significant potential stormwater benefits of soil health practices including increased infiltration, improved treatment of pollutants present in highway stormwater runoff. The improved management of stormwater will result in improved water quality of runoff from MnDOT highway systems resulting in greater protection of the many water resources here in Minnesota.”

The objectives are:

  1. Evaluate resilience to water availability through organic amendment (e.g., compost) addition through greenhouse stormwater experiments
  2. Optimize amendment loadings based on resilience
  3. Develop a “recipe” for improving the health of poor soils based on soil health measurements, by amending the soil with compost or other organics

Project Details

  • Start Date: 05/16/2025
  • Estimated Completion Date: 06/30/2027
  • Funding: MnDOT
  • Principal Investigator: Bora Cetin
  • Co-Principal Investigators: Angela Farina
  • Technical Liaison: Warren Tuel

Details of the research study work plan and timeline are subject to change.

To receive email updates about this project, visit MnDOT’s Office of Research & Innovation to subscribe.