Tag Archives: featured

Maintenance Operations

New videos show how frost heave ravages roads

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Regardless of whether you’re familiar with the term “frost heave,” if you live in Minnesota and drive on the roads, you’re already familiar with its destructive capacity. Many of the dips, bumps, potholes and cracks that appear on our roads every spring are a direct result of frost heave, which occurs when water accumulates in the soil beneath the pavement and begins freezing and then thawing along with the changing seasons. The resulting expansion and contraction weakens the road base and leaves it susceptible to damage from traffic loading.

These new videos produced by the Local Road Research Board explain how frost heave works, and describe some of the strategies public works departments use to combat it. The top video is is the shortened, executive-summary version, while the bottom video is the full, 13-minute version meant for transportation professionals.

Maintenance Operations

Patching pavement with microwaves and magnetite

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On Wednesday, I had a chance to watch a demonstration of a uniquely Minnesotan pavement patching technology that combines an industrial-strength microwave with a special asphalt mix. What makes it “uniquely Minnesotan?” In addition to having been developed by University of Minnesota researchers and a Monticello-based company (and with some funding from MnDOT), this innovative method involves a special asphalt mix using magnetite, a mineral that abounds on Minnesota’s Iron Range.

It also addresses a very Minnesotan transportation problem: winter pavement repair. In the video above, Kirk Kjellberg of Microwave Utilities, Inc., highlights some of the benefits of using the 50,000-watt microwave to heat the pavement during patching. In addition to creating a longer-lasting patch, the microwave is considerably faster than many alternative techniques. The technology is still relatively new, but its supporters claim it allows for pavement repairs in the middle of winter that are as strong and durable as the ones road crews do in the summer.

The demonstration, which was organized for members of the Local Road Research Board, took place at MnDOT’s District 3 training facility in St. Cloud.

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Public Transit

New report: NEMT Coordinators in Minnesota

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Under Minnesota’s fee-for-service Medical Assistance (MA) program, Minnesota counties are responsible for providing transportation assistance to MA recipients so they can obtain health-care services. This assistance is commonly referred to as non-emergency medical transportation (NEMT).

NEMT_cover_screenshot.jpgA new report, NEMT Coordinators in Minnesota: A Survey of How Minnesota Counties Use Coordinators to Deliver Non-Emergency Medical Transportation, published by the Minnesota Council on Transportation Access based on research conducted by researchers at the University of Minnesota’s Humphrey School of Public Affairs documents how select Minnesota counties use transportation coordinators in providing and administering NEMT under the state’s fee-for-service MA program.

In the surveyed counties, the use of a coordinator generally made the delivery of NEMT more efficient and streamlined than it had been with previous approaches. Coordinators have increased efficiency principally by centralizing both transportation expertise and the ride arrangement processes, either internally within the county government or externally with an outside coordinator.

About the Council

The Minnesota Council on Transportation Access (MCOTA) serves as a clearinghouse to address transportation coordination topics from a statewide perspective. The Minnesota State Legislature established the group in 2010 (MN Statute 2010 174.285). The group includes member representatives from thirteen agencies.

MCOTA’s work focuses on increasing capacity to serve unmet transportation needs, improving quality of transit service, improving understanding and access to these services by the public, and achieving more cost-effective service delivery. In addition, fostering communication and cooperation between transportation agencies and social service organizations leads to the creation of new ideas and innovative strategies for transportation coordination and funding.

Learn more at www.CoordinateMNTransit.org.

Public Transit, Traffic and Safety

Congestion-reduction measures on I-35W: How well do they work?

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In an effort to combat congestion in our country’s urban areas, the United States Department of Transportation launched the Urban Partnership Agreement (UPA) program in 2007. The program infused nearly $900 million into transportation-related projects in four cities nationwide, including the Twin Cities metropolitan area. Minnesota’s projects—which include the installation of MnPASS dynamic toll lanes and variable message signs—focused on improving traffic flow in the I-35W corridor between Minneapolis and the city’s southern suburbs.

To understand the effectiveness of measures implemented under the UPA program, a team of University of Minnesota researchers examined three separate but related areas: the effects of a new variable speed limit (VSL) system, the impact of severe weather conditions on road safety, and the behavior and traffic impacts of bus rapid transit operations. Their work was funded by the Intelligent Transportation Systems Institute, a part of CTS.

Key findings included:

  • Drivers don’t typically comply with advisory speed limits posted on VSL signs along the I-35W corridor during congested conditions, but they may use them to help gauge and prepare for downstream congestion—resulting in a smoother and possibly safer traffic flow
  • Some parts of the corridor’s shoulder lanes—which are opened to traffic during specific times of the day as part of the UPA program—contain low areas that can flood during heavy rains
  • Buses traveling on the corridor underuse the MnPASS lane. In addition, bus lane changes (from stations located in the median to those located on the right side of the highway) can generate visible disturbances during moderate and heavy congestion, but they don’t seem to contribute to the breakdown of traffic flow

For more information, read the full article in the September issue of Catalyst.

Traffic and Safety

‘Intelligent’ traffic drum could help prevent work-zone tragedies

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2012-26 Image
A prototype of the Intelligent Drum Line system.

Work-zone safety is a serious, ongoing challenge for transportation agencies. According to MnDOT, the current three-year average for Minnesota work zones is 1,819 crashes and seven fatalities per year. And that’s not counting near-misses: just talk to anyone who has worked as a flagger, and they will likely have a story about diving into a ditch to avoid being hit by a distracted driver. Consequently, MnDOT is constantly exploring ways to make work zones safer — which brings me to the photo above.

What you’re looking at is no ordinary traffic cone. It’s a prototype of a new warning device called the Intelligent Drum Line system — basically a modified orange traffic drum packed with electronics that can detect speeding drivers and blast them with audiovisual cues to let them know they’re entering the work zone too fast.

Our new technical summary explains the details of the new system, which was developed at the University of Minnesota, with funding and in-kind assistance from MnDOT:

The prototype design uses two modified traffic drums placed 1 to 3 feet from the shoulder of the road and 300 to 400 feet apart. Sensors in the first drum detect vehicles, measure their speed and distance, and communicate this information to the second drum…

When the IDL system detects an oncoming vehicle traveling faster than a threshold speed, the system activates visual warning systems in both drums and initiates a countdown. When the speeding vehicle is approximately 1 second away from the first drum, the system activates an air horn to warn the driver.

As the vehicle passes the first drum, the audible alarm terminates and the system transmits a command to the second drum to start another countdown. When the vehicle is approximately 1 second away from the second drum, the system activates another audible alarm.

Testing of the IDL system at MnROAD has been successful; however, researchers still need to study how drivers react to the system in real-world conditions. Before they can do that, the design will have to be refined so that it can pass Federal Highway Administration crashworthiness tests. On a related note, MnDOT is currently funding a separate University of Minnesota study into which technologies are most effective at capturing drivers’ attention in work zones. The study will include visual and auditory cues similar to the ones used in the IDL prototype.

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