Motorists driving dangerously in work zones present a safety risk to workers and themselves. Alerting these drivers about their driving behavior before they reach the work zone could reduce the number of work zone crashes and enhance work zone safety. This project developed and evaluated the performance of a device that provides audio and visual alerts to drivers whose vehicles are approaching work zones at a high speed and on a dangerous trajectory.
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Evaluating the Safety Impacts of Select Pedestrian Infrastructure
To enhance pedestrian safety at intersections, transportation agencies may install temporary or permanent infrastructure such as curb extensions or pedestrian refuge islands. While more permanent infrastructure with concrete is generally considered effective, specific details about temporary infrastructure with flexible delineators (or bollards), such as installation, use and safety impact, would be valuable to optimize cost-effectiveness. This project evaluated both temporary and permanent pedestrian infrastructure at crossing sites to measure the effects on pedestrian safety and driver behavior.
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Assessing Recycled Pavement for Use in Road Design
Cold recycling road pavement materials into new road construction is a cost-effective and sustainable practice. However, the properties of these materials must be characterized to adequately design pavement structures. This project developed a framework and tool for transportation agencies to estimate the key material properties of cold recycled materials incorporated into road designs.
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Limiting Pavement Damage from Detours
Detours for highway construction projects direct heavy freight vehicles onto local roads that were not designed to accommodate the frequency of heavy loads. Detours to these local roads often accelerate pavement deterioration that shortens their service life and requires additional repair. This project examined the structural and economic impacts of detours on local roads to develop a framework for optimizing detour routes that limit pavement damage while maintaining traffic mobility.
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Assessing Rejuvenators That Extend Pavement Service Life
Over time, asphalt pavement becomes stiff and brittle due to oxidation, often leading to surface cracking and distress. To mitigate these damages and extend the service lives of roads, transportation agencies may apply a spray-on rejuvenator (SOR) to restore essential components of the asphalt. This project investigated the short- and long-term effectiveness of 12 SORs that state and local transportation agencies may consider for future use.
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Increasing Equity in Transportation Investments
Historically, equity has not been a primary objective in the transportation infrastructure investment planning process. By effectively incorporating equity into the process, underserved communities and Native nations can realize increased benefits from transportation improvements. This research explored effective strategies for incorporating equity in transportation capital investment planning and provides guidance to transportation agencies, planning organizations and Native nations.
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Evaluating Taconite as a Lower Cost Friction Treatment
High friction surface treatments (HFSTs) on Minnesota roads are composed of imported, industry standard calcined bauxite aggregate. This material is expensive, and producing it is energy-intensive. Taconite aggregate, a by-product of the Minnesota mining industry, is a potential alternative to calcined bauxite that is less expensive. This research compared taconite and calcined bauxite in field skid resistance performance testing to determine the feasibility of using taconite in place of calcined bauxite in HFST applications.
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Evaluating Road Designs That Use Lower Quality Aggregate
Aggregate materials used in the base and subbase layers of pavements provide structural support and drainability to Minnesota roads. But the supply of locally available high-quality aggregate material is becoming increasingly scarce. This project explored sustainable and cost-effective solutions for constructing durable flexible pavement roads with lower quality aggregate material.
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Developing Biochar Specifications for Stormwater Management
Effective stormwater management helps keep roadway contaminants from entering Minnesota’s lakes and streams. Management practices include soil and vegetation in roadside bioretention systems that filter heavy metals and hydrocarbons created by vehicles. Based on other studies, retention and transformation of roadside pollutants should be improved by biochar application to existing or engineered soils. Abundant sources of biomass can be used to produce biochar, a soil amendment with numerous benefits. MnDOT and local agencies identified biochar specifications for effective use in stormwater treatment to support the next phase of testing and development of biochar design guidance.
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Evaluating Strategies to Prevent Early-Age Bridge Deck Cracking
Premature cracking in reinforced concrete bridge decks is expensive to repair and may lead to rapid bridge deterioration. Despite changes to mix designs, transverse cracking after casting continues to be a problem in Minnesota. This project evaluated alternative concrete mix designs and reinforcement strategies to mitigate early-age bridge deck cracking, reduce maintenance costs and extend bridge deck service lives.
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Crossroads 