Pavement Preservation Techniques for Local Agencies

Cities and counties need affordable pavement preservation treatments, but preservation strategies are often geared towards higher-volume roads. The Minnesota Local Road Research Board has developed new guidance on five lower-cost treatments that is more applicable to local agencies and can be used to preserve pavements based on the type and severity of pavement distress.

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GFRP Rebar Shows Promise for Use in Bridge Decks

Reinforced concrete bridges are built to handle heavy loads and routine traffic for 75 years or more. But bridges in climates like Minnesota’s are exposed to moisture and chlorides from road salts that may penetrate these structures and corrode the steel.

In a recently completed research project, funded by MnDOT and the Local Road Research Board, researchers studied a rural bridge built in 2017 near Elgin, MN, that used glass fiber–reinforced polymer (GFRP) rebar in the bridge deck. They found that GFRP performed well, proving sufficiently strong for use as an alternative to corrosion-susceptible steel rebar.

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Improving Roadside Turfgrass Establishment

Just in time for spring, new guidance is available from the Minnesota Local Research Board on the best irrigation methods to establish fresh turfgrass. Researchers tested five irrigation methods for watering new installations of salt-tolerant turfgrass. They developed an instructional course for contractors and guidance for homeowners to promote successful turfgrass installation.

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Improving Traffic Volume Estimates By Monitoring Health of Loop DetecTORS

A newly developed system helps traffic engineers quickly spot failing loop detectors, which are used to monitor traffic volumes on Minnesota highways. The software program, developed by the University of Minnesota-Duluth for the Minnesota Department of Transportation, evaluates loop detector data and reports current loop detector health in an easy-to-read graphic format, making it easy to identify loop detectors in need of repair and which loop detectors should be used for the most accurate traffic counts.

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Redesigned iron-enhanced ditch checks could help filter pollutants from stormwater runoff

This article was originally published in Catalyst, April 2020.

The Minnesota Department of Transportation (MnDOT) is exploring innovative ways to filter pollutants from stormwater runoff and meet permit requirements for construction projects. In a recent study, U of M researchers documented the performance of an iron-enhanced ditch check filter to remove phosphates from stormwater. They found that the filter was effective, though its performance decreased over time.

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Transverse Rumble Strips: Another Tool for Rural Road Safety?

Rural intersections account for 30% of crashes in rural areas and 6% of all fatal crashes, representing a significant but poorly understood safety problem.

Transverse rumble strips are one low-cost measure that some states have deployed to reduce rural intersection crashes.

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Regional effort tests turfgrass performance in cold climate states

This article was originally published in Catalyst, April 2020.

Vibrant green grass along roadways is a common sight across urban and rural landscapes in Minnesota and many other states, but its survival is a significant challenge—especially in cold climates. Roadway salt and other stressors can cause turfgrass installations to fail, requiring expensive reseeding or sodding efforts.

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Low-Cost Pavement Condition Forecasting Software Eases Local Road Planning

The Minnesota Local Road Research Board (LRRB) has added pavement condition forecasting technology to an existing, web-based roadway inventory tool that will enable counties to generate low-cost maps and reports that help them prioritize their work by showing how roadway conditions will look under different construction scenarios for decades to come.

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Earth Day 2020

April 22 is Earth Day!

Climate change & the environment is one of five research strategic priorities that guide the work of the state transportation research program.

This includes research projects specific to endangered & threatened species, wetland protections, salt use and incursion, congestion impacts on air quality, and the impacts of road construction and maintenance activity on the environment.

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Minnesota's transportation research blog