All posts by mndotresearch

Strategies for Recruiting and Retaining Minnesota’s Transportation Workforce

Across the transportation industry, public and private employers are experiencing workforce shortages and an uncertain future. As older employees retire and younger workers fill their roles, organizations must naturally adjust to accommodate their changing workforce. In the transportation industry, shifting demographics have also brought new attitudes regarding technical jobs. The result is that fewer engineers and other highly skilled professionals are entering the field, and keeping those who do is becoming increasingly difficult. To address this changing landscape, transportation agencies of all sizes must be prepared to meet the challenges ahead or risk falling behind.

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Evaluating the Impact of J-Band on Pavement Service Life and Crack Resistance

Potholes and other pavement failures in asphalt typically occur at the seams between lanes, where the mixture loses density during compaction because the edges are not confined like they would be with cement concrete forms. Researchers found that spraying J-Band, a void-reducing asphalt membrane (VRAM), in a band along longitudinal joints before asphalt layers are applied increased bond strength, lowered permeability and air void levels, and improved crack resistance.

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Investigating Asphalt Pavement Stripping Under Seal Coats

A recent Local Road Research Board (LRRB) study confirmed that increased freeze-thaw activity during Minnesota winters leads to delamination of seal coats from underlying pavements. Researchers identified optimal seal coat mix combinations and site conditions that may ensure effective seal coating of asphalt pavements in cities and counties around Minnesota. 

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Local Guidance for Bicycle Facility Design

A quick reference guide is now available to help local agency planners and designers select the best bicycling facilities for their system. This guide walks local agencies through the selection and design process, and directs users to specific places within design manuals for details on facility questions.

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Smartphone App Gives Crossing Guidance to the Visually Impaired

In a recent research project, MnDOT sought to validate a smartphone app designed to guide pedestrians who are blind or visually impaired through signalized and unsignalized intersections. The project succeeded in showing the app’s effectiveness in tests at six intersections in Stillwater, Minnesota.

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Low-Volume Road Runoff Analyses Suggest Optimal Treatments

Assisted by many county agency staff, researchers collected and analyzed runoff from low-volume rural roads over two years to determine how their contaminants compared to those of high-volume roadways. Results documented that runoff from low-volume roads has a lower contaminant concentration and that ditches and swales can be used to effectively treat rural road runoff.

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Understanding Rural Pedestrian Travel Behavior and Safety Issues

In collaboration with the Advocacy Council for Tribal Transportation and other tribal members, University of Minnesota researchers monitored 10 roadway sites specified as safety risks for pedestrians on four rural Minnesota reservations. Analysis of videos and group brainstorming produced a shortlist of potential countermeasures that could be incorporated into future highway projects.

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Monitoring Performance of an Iron-Enhanced Stormwater Filtration System

A recent study determined the effectiveness of a two-cell iron-enhanced stormwater filtration basin to remove phosphorus from highway stormwater runoff collected from 2012 to 2018. Researchers recommended design changes that would allow for more accurate monitoring of these filter basins.

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