Hot Topics is our electronic newsletter highlighting new publications and resources from a variety of sources.
Photo courtesy David Gonzalez, MnDOT
For years doctors have told people to stick to a low-salt diet. According to the Minnesota Pollution Control Agency (MPCA), our roads—and waters—should follow the same advice.
This was the common thread of the 2013 Road Salt Symposium, which brought together experts in the winter maintenance industry, environmental groups, cities, counties, and state transportation departments.
According to Brooke Asleson, MPCA project manager for the Twin Cities Metro Area (TCMA) Chloride Project, "It only takes one teaspoon of road salt to permanently pollute five gallons of water. We are trying to spread the word that less is more when it comes to applying road salt because at high concentrations, chloride can harm the fish and plant life in our waters."
One of the symposium presentations was about a salt-savings tool under development as part of the TCMA project. Connie Fortin said the tool will let users analyze their current winter maintenance operations—such as salt delivery and storage practices—and find potential salt-saving opportunities unique to each organization. The intent is to provide practical, customized best management practices that won't compromise safety—and that reduce salt budgets to boot.
Read more about these presentations and others on the symposium web page. The annual event is sponsored by the Freshwater Society, in collaboration with Fortin Consulting Inc., the MPCA, and Minnesota LTAP. It is worth one elective credit in Minnesota LTAP's Roads Scholar Program.
The Cushion-Release Push Frame helps take
the jolt out of winter maintenance.
A mechanical linkage technology developed in part with funding from the Minnesota Local Road Research Board (LRRB) Local OPERA Program—the Cushion-Release Push Frame—is getting some use this winter, as well as some favorable press coverage.
Hitting an uneven pavement edge or an obstacle like a manhole cover gives a jolt to tractor-mounted snow blowers. The push frame can be installed on snow blowers, front-end loaders, and other equipment to help "walk" over obstacles by absorbing the impact.
The technology was put to use in St. Paul and Bloomington this winter. It's also been used in Chanhassen, Alexandria, and Sauk Center, as well as in Fargo, North Dakota, and the U of M Duluth campus.
An article about the technology—"Minnesota man's invention makes a snowblower better"—ran in the December 30, 2012, Minneapolis StarTribune.
The OPERA website has a fact sheet describing it: Cushion Release Push Frame and Weight Transfer Kits. More information about the push frame, including video of it in action, is at Safeloader.com.
Did the story above make you catch the inventor bug? If so, consider applying for funding from the Local OPERA Program. The program is still accepting research-funding proposals for FY 2013. Innovative research proposals related to timely, relevant transportation topics are requested. Researchers are welcome to submit more than one proposal. To apply, complete and submit the project proposal form available on the OPERA website.
In December, the LRRB approved the following research projects:
If you would like to take part in shaping any of these projects, please contact Sandy McCully of MnDOT at 651-366-3768, Sandra.McCully@state.mn.us.
In an effort to increase roadway safety, the LRRB has produced three YouTube videos to education the public:
The first two videos help drivers understand the correct purpose and function of speed limits and stop signs—thus minimizing the number of requests for lower speed limits and new stop signs throughout local neighborhoods. The third video encourages drivers to keep roads safe and smooth by reporting potholes.
Each three-minute video features interviews, animations, and on-location footage. Access these and other videos on the LRRB Resources page.
Minnesota LTAP has launched an online work-zone safety tutorial. The free tutorial offers a convenient opportunity for new, seasonal, or temporary staff to learn about the fundamentals of work-zone safety and the basic concepts of the work-zone area before arriving at the job site. This tutorial addresses many of the hazards inherent in road and street work and how these dangers can be minimized to keep motorists, pedestrians, and employees safe.
The training includes a slide presentation, pictures, video, and a question/answer section to check comprehension of the material. All reading assignments are available online within the tutorial, so no additional books or materials need to be purchased.
Give it a try and get ready for your work zones this construction season.
Load securement is one of the topics at this
year’s Demo Day
The Minnesota Roadway Maintenance Training and Demo Day will be held this year on May 1 at the Olmsted County Fairgrounds in Rochester. The topics this year are:
All topics include a classroom-style presentation in the morning and a hands-on outdoor demonstration in the afternoon. Each outdoor demonstration can have up to three to four stations for demonstrations.
The event is sponsored by Minnesota LTAP, MnDOT, the LRRB, and the FHWA, in partnership with the American Public Works Association/Minnesota Chapter and Minnesota Street Superintendents Association. It will include a Roads Scholar graduation ceremony, and attendees will earn a Road Scholars credit.
Minnesota LTAP offers another online course—Gravel Road Maintenance and Design. It provides a high-quality training option at a low cost, and it counts as one required credit in the Roads Scholar Program. The course was developed by Minnesota LTAP in partnership with the LRRB.
Minnesota LTAP's Road Scholar Program combines LTAP and CTAP workshops and other training into a structured curriculum. Enrollment is free. For details, visit the website or contact Mindy Carlson with any questions.
The Minnesota Filter can be used in many
applications, such as this site in Maplewood.
Photo courtesy SAFL and Andrew Erickson
Researchers at the University of Minnesota's St. Anthony Falls Laboratory (SAFL) have identified techniques to remove the dissolved compound phosphate from stormwater, with excellent results. Their iron-enhanced sand filtration system, named the Minnesota Filter, has been installed in a number of locations around the Minneapolis–St. Paul metro region. The research was funded by the Minnesota Local Road Research Board. Read "New treatment practice removes dissolved phosphates from stormwater" in the December 2012 CTS Catalyst.
SAFL researchers also invented a low-cost device to boost the performance of sump manholes for cleaning stormwater. The SAFL Baffle slows down water rushing into sumps during heavy storms and prevents it from picking up sediment that has settled there during low-flow periods. Read "Device cleans stormwater and saves money for locals" in the fall 2012 Technology Exchange.
SAFL researchers recently completed a project aiming to improve culvert design, installation, and monitoring throughout Minnesota. As part of the study, partly funded by MnDOT, the research team examined pipe material options, evaluated the current practice, and provided guidelines to help optimize culvert design for service life and performance.
Read "Improving culvert design and service life in Minnesota" in the December 2012 CTS Catalyst or download the research report.
Best Practices: Culvert Replacement (Ohio DOT, 2012)
This DVD focuses on best practices for replacing culverts.
Decision Tree for Stormwater BMPs (MnDOT, 2011)
The tool assists city and county public works staff in the selection of best management practices appropriate for specific projects.
Porous asphalt test cell on the MnROAD
Speakers at this year's TERRA (Transportation Engineering and Road Research Alliance) Pavement Research Conference discussed topics ranging from intelligent compaction to surface treatments to pavement preservation. Presentation slides and selected videos are available at the 2013 TERRA Pavement Conference web page. The spring 2013 issue of the Minnesota LTAP Exchange newsletter will include articles about several of the presentations.
TERRA has also published a new fact sheet about porous asphalt. The fact sheet provides an overview of this innovative pavement technology, including details from a TERRA-initiated study about the performance of porous asphalt in cold climates. Porous pavement primarily has been used in parking lots, recreational areas, and low-volume roadways, but is attracting attention as a tool in addressing environmental issues.
Evaluation of the Safety Edge in Iowa: Phase II (Iowa DOT, FHWA; 4.3 MB PDF)
This report documents the evaluation of Safety Edge projects and results in Iowa and includes an array of conclusions and practical recommendations.
Pavement Edge Treatment (Washington State DOT; 2.3 MB PDF)
This report explains projects built with four different devices that allow vehicles leaving the roadway to have a gentler slope to navigate when remounting the pavement.
Guide to Concrete Overlays of Asphalt Parking Lots (CP Tech Center, Iowa State)
This guide helps select, design, and construct successful concrete overlays on existing asphalt parking lot pavements that serve multifamily residential, public, or commercial buildings.
Polyester Polymer Concrete Overlay (Washington State DOT; 3.4 MB PDF)
This report details a trial application of polyester polymer concrete to determine possible repair strategies for pavement damaged from extensive studded tire wear.
Use of Reclaimed Asphalt Pavement in Concrete Pavement Slabs (University of Florida and Florida DOT; 6.9 MB PDF)
This report evaluates the feasibility of using reclaimed asphalt pavement as aggregate replacement in concrete.
Performance Evaluation of JRCP with Stabilized Open-Graded Drainage Course (Michigan DOT; 1.2 MB PDF)
MDOT has continued to identify opportunities to stabilize recycled concrete pavement bases with portland cement concrete.
Performance Testing for Superpave and Structural Validation (FHWA)
This report provides the findings from two Transportation Pooled Fund (TPF) research projects—TPF-5(019): Full-Scale Accelerated Performance Testing for Superpave and Structural Validation, and SPR-2(174): Accelerated Pavement Testing of Crumb Rubber Modified Asphalt Pavements.
Evaluation of High-Volume Fly Ash Mixtures (Paste and Mortar Components) Using a Dynamic Shear Rheometer and an Isothermal Calorimeter (FHWA)
This TechBrief is a technical summary of a study focused on developing a rationale for using a dynamic shear rheometer and an isothermal calorimeter as practical, quick scanning tools for predicting and assessing early-age behavior of concrete mixtures containing different types and levels of cement and fly ash; identifying incompatible blends; and verifying performance.
Sustainable Highways Self-Evaluation Tool (FHWA)
INVEST (Infrastructure Voluntary Evaluation Sustainability Tool) is a free web-based collection of best practices designed to help transportation agencies integrate sustainability into their programs and projects.
Performance Contracting for Construction: A Guide to Using Performance Goals and Measures to Improve Project Delivery (FHWA)
This newly updated guide walks through the process for using performance contracting on a typical reconstruction or rehabilitation project.
Innovative Bridge Construction for Minnesota Local Roads (LRRB and MnDOT; 7.6 MB PDF)
This report outlines new bridge design and construction methods used by Minnesota counties. Innovative techniques (several of which have already been used in other states) range from GRS abutments to crash-tested open metal railings. The report also includes implementation ideas and recommendations as well as federal funding opportunities.
Sample Guide Specifications for Construction of Geosynthetic Reinforced Soil-Integrated Bridge System (FHWA)
Agencies can use the sample specifications as a basic template for developing their own standard specifications for GRS-IBS, incorporating local experiences and practices where applicable.
GRS Bridge System Pilot Project (WisDOT)
This video highlights a pilot project using geosynthetic-reinforced soil in an integrated bridge system (GRS-IBS) on a low-volume state trunk highway bridge in northwest Wisconsin. The video discusses the research that led to the project, the lessons learned from the implementation of the technology, and the future use of the system through the FHWA Every Day Counts initiative.
Application of Radiographic Testing to Multilayered Gusset Plate Inspection (FHWA)
This TechBrief discusses the efficacy of radiographic inspection for these types of gusset plates.
Experimental Validation of Bracing Recommendations for Long-Span Concrete Girders (University of Florida and Florida DOT; 16.9 MB PDF)
This report evaluates roll stiffness for bearing pads under skewed and sloped conditions by using experimental data from test device.
Theoretical and Field Experimental Evaluation of Skewed Modular Slab Bridges (Maryland DOT; 20.2 MB PDF)
This report examines the causes of reflective cracking on recently built skewed bridges and proposes revisions to bridge design standards concerning the number, orientation, and location of the transverse post-tensioning, specifically in reference to a bridge's skewness.
Federal Highway Administration 100-Year Coating Study (FHWA)
Eight coating systems were selected for the study—three three-coat systems consisting of organic, inorganic, and moisture-cured zinc-based primers; four two-coat systems with various combinations of zinc-based primers and organic top coats; and a single-coat system of calcium sulfonate alkyd.
Evaluating Pedestrian Safety Improvements (Michigan DOT; 4.3 MB PDF)
This study evaluated the impact of new pedestrian countermeasure installations on pedestrian safety to assist in informing future pedestrian safety initiatives.
Non-Motorized User Safety: A Manual for Local Rural Road Owners (FHWA)
This manual provides a concise "toolbox" of resources and information for addressing non-motorized safety concerns and provides evaluation methods for locally implemented initiatives to address the safety of non-motorized users.
Design Guidance for High-Speed to Low-Speed Transitions Zones for Rural Highways (TRB)
This report presents guidance for designing the transition from a high-speed rural highway to a lower-speed section, typically approaching a small town. It also provides design guidance for selecting geometric design, traffic control device, pavement surface, and roadside treatments for transitioning from high- to low-speed roadways on rural highways.
Integrated Risk Management for Improving Internal Traffic Control, Work-Zone Safety, and Mobility During Major Construction (Iowa State University Institute for Transportation)
This report proposes an integrated approach to researching work-zone safety issues and mobility in order to improve the safety of highway construction work zones.
Best Practices for Emergency Rerouting (Michigan DOT)
This report lays out a statewide manual to support regions in updating or establishing a documented set of practices for maintaining emergency rerouting plans.
Before- and-After Safety Study of Roadways Where New Medians Have Been Added (Florida DOT)
This report evaluates the safety impact of median conversion from two-way left-turn lanes to raised medians in Florida.
Best Practices in the Use of Hybrid-Static Dynamic Signs (Florida DOT)
This report reviews existing hybrid sign applications both in the U.S. and around the world, including the application areas of speed control, parking guidance, and graphical route information.
Report on Red-Light Traffic Control Signal Monitoring Systems: Second Annual Report (New Jersey DOT; 287 KB PDF)
This report describes a traffic control signal monitoring systems pilot program and analyzes safety data for all authorized systems where violations have been issued for a one-year period.
Safety Benefits of Implementing Adaptive Signal Control Technology: Survey Results (Illinois Center of Transportation; 975 KB PDF)
This report considers the safety benefits and costs associated with implementing adaptive signal control technology, specifically the system type, detection type, and cost of implementation.
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