Tag Archives: transportation research

Flume research simulates Red River flooding to test road protections

Flooding in the Red River Valley is an almost annual occurrence, and the cost to roads, property and lives is huge.

Highway 1 gets torn up year after year, only to be rebuilt in time for next year’s flood, joke residents in the little town of Oslo, which becomes an island whenever the roads close.

While not much can be done to prevent swollen farm fields from overflowing, what if a road embankment itself could be bolstered to prevent physical damage to the underlying structure of the road?

“We can’t just raise the road because it would create backwater upstream,” explained JT Anderson, Assistant District 2 Engineer. “Our best bet is to let the water over-top the road and try to protect the road when it does.”

Researchers have built a flume inside the University of Minnesota’s St. Anthony Falls Laboratory to test six methods of embankment protection specific to the needs of towns like Oslo.

“It is not uncommon for one over-topping site to have a half-mile long stretch of road being damaged,” said university research engineer Craig Taylor. “One road being protected should cover the cost of the study and the cost of deploying the erosion control product for that road.”

Nationally, research of this kind has mostly been restricted to high-intensity flooding.

“Those really high-depth, short duration events, you can only protect an embankment with concrete and boulders,” Taylor said. “With longer duration, low-depth floods, we may be able to protect roads with soft armoring, like reinforced vegetation.”

The damage in northern Minnesota has been the worst on east-west roads, where the river flow runs perpendicular to the center of the road, causing the road to act like a dam and the water to jump at the edges.

“It eventually eats through that road embankment and makes the road collapse,” Anderson explained.

Researchers will examine how a cross-section of a road holds up under various erosion control methods at different levels and speeds of water-flow.

The damage from flooding was less in 2010 after engineers added rocks and vegetation to the side of Highway 9, near Ada.
The damage from flooding was less in 2010 after engineers added rocks to the side of Highway 9, near Ada, Minn.

One test will be to slow the flow of water by covering the road shoulder with a rubberized membrane and temporary water-filled tubes.

Permanent schemes — such as turf reinforcement mats and rocks — will also be tested.

“These methods have been deployed in the field, but you never really know under which conditions they survived or failed,” Taylor said.

In the Red River Valley, MnDOT engineers have tried a combination of vegetation and boulders, as well as concrete blocks covered with topsoil, to protect highways. Flattening a slope is another option.

“I expect that a single erosion protection technique will not cover every situation our road embankments may be exposed to at any given location,” Anderson said.  “Rather, I expect we would look at using several different techniques in concert to develop an effective erosion protection system for the expected velocities.”

Value capture alternative finance model tested on Highway 610

Those who use the roads in Minnesota are generally those who pay for them — through gasoline and vehicle taxes.

But motorists aren’t the only ones who benefit when a new interchange is built or a highway is improved. Home and business values along the corridor go up and the price of undeveloped land can skyrocket.

With highway funds strapped, a new method of funding road expansion, called “real estate value capture,” is garnering attention.

This emerging technique strives to identify beneficiaries of transportation improvements beyond just the highway user, so they provide their fair share of the costs — a concept not dissimilar from residential street assessment.

For instance, a local government might dedicate the additional property tax revenue generated due to a new highway to offset some construction costs, or collect fees on land that is developed near an interchange.

However, value capture is a relatively new technique that has been used primarily for transit projects. To be considered for roads or bridges, questions need to be addressed about potential revenue, impacts and public acceptability.

In a new case study, researchers use a long-delayed planned extension of Highway 610 in Maple Grove to model the impact of a completed highway on nearby property values, and, for the first time, quantify the potential revenues from several value capture strategies.

With properties near new highway exits worth an additional $65,450 more per acre, researchers calculated that $37.1 million in revenue could be generated through assessments on existing development and impact fees for future development.

Other strategies explored include tax-increment financing and private-public development of undeveloped parcels, in which revenue generated by that development is split.

“This research demonstrates a way to estimate the value of transportation improvement and to communicate that to the public,” said principal investigator Jerry Zhao, an associate professor of public administration at the University of Minnesota’s Humphrey School of Public Affairs.

This map projects the anticipated increase in estimated market value (EMV Change) of parcels near Highway 610 that will result from completion of the highway and construction of exits at the two locations marked in purple. The impacted parcels are currently vacant, farmland or residential.
This map projects the anticipated increase in estimated market value (EMV Change) of parcels near Highway 610 that will result from completion of the highway and construction of exits at the two locations marked in purple. The impacted parcels are currently vacant, farmland or residential.
Study links:
    • Real Estate Value Capture: An Emerging Strategy to Pay for New Transportation Infrastructure – Technical Summary (PDF, 1 MB, 2 pages);  Final Report (PDF, 5 MB, 36 pages).

MnROAD earns concrete pavement association award

Staff from MnROAD, the Minnesota Department of Transportation’s cold weather road research facility in Albertville, Minn., were presented with the Marlin J. Knutson Award for Technical Achievement by the American Concrete Pavement Association in December.

The award cites the facility’s well-deserved reputation for being a place where both agency and industry ideas are put to the test. This award was presented as a tribute to the agency’s commitment to learning and putting ideas into practice.

The Marlin J. Knutson Award for Technical Achievement is presented to an individual or group who has made significant contributions to advance the development and implementation of technical innovations and best practices in the design and construction of concrete pavements.

(far right) Gerald Voigt, ACPA president and CEO, presented MnDOT with the Marlin J. Knutson Award for Technical Achievement during a ceremony in December. Receiving the award are (from left) Luke Johanneck, Bernard Izevbekhai, Roger Olson, Tom Burnham, Glenn Engstrom, Maureen Jensen and Sue Mulvihill. (Photo courtesy of the ACPA)
(Far right) Gerald Voigt, ACPA president and CEO, presented MnDOT with the Marlin J. Knutson Award for Technical Achievement. Receiving the award are (from left) Luke Johanneck, Bernard Izevbekhai, Roger Olson, Tom Burnham, Glenn Engstrom, Maureen Jensen and Sue Mulvihill. (Photo courtesy of the ACPA)

“MnROAD is helping to make roads last longer, perform better, cost less, construct faster, and have minimal impact on the environment,” said Gerald Voigt, ACPA president and CEO. “It is a model for other agencies to follow.”

MnROAD is a pavement test track initially constructed between 1991-1993. It uses various research materials and pavements and finds ways to make roads last longer, perform better, cost less to build and maintain, be built faster and have minimal impact on the environment. MnROAD consists of two unique road segments located next to Interstate 94.

Staff from the MnROAD facility in Albertville were recognized during the ACPA’s Distinguished Service and Recognition Awards ceremony in December. (Photo by David Gonzalez)
Staff from the MnROAD facility in Albertville were recognized during the ACPA’s Distinguished Service and Recognition Awards ceremony in December. (Photo by David Gonzalez)

This article, authored by Rich Kemp, originally appeared in Newsline, MnDOT’s employee newsletter. 

LRRB research showcased at pavement and dust control conferences

The Transportation Engineering and Road Research Alliance and Road Dust Institute conferences are being jointly held this week in Minneapolis. Among the many research topics being presented are several recently completed studies funded by the Minnesota Local Road Research Board.

The LRRB, which celebrates its 55th anniversary this year, is one of only two statewide organizations in the United States that fund transportation-related research projects and education on behalf of local governments.  In honor of the TERRA and dust control events, we thought we’d take the opportunity to highlight a few of the latest pavement and dust control-related research projects from the LRRB.  If you’re at TERRA today, be sure to stop by their booth and check out their latest research results, videos and more.

Recycled Asphalt Pavement: Study of High-RAP Asphalt Mixture on Minnesota County Roads 

This report summarizes the field performance of local roads containing recycled asphalt pavement (RAP), associated field and laboratory work with asphalt activation, and design and performance testing of high-RAP bituminous mixtures. Conclusions include:
• Transverse cracking performance of county highways averaging 20 to 26 percent RAP was improved when PG 52-34 binder was used.
• Coarse aggregates from plant mixing achieved a more uniform coating and were subjected to less abrasion than those from laboratory mixing.
• IDT critical temperature results showed that the addition of RAP significantly increased the critical temperature, predicting less crack resistance.

Research using Waste Shingles for Stabilization or Dust Control for Gravel Roads and Shoulder

Minnesota generates more than 200,000 tons of shingle waste each year. While a small portion of recycled asphalt shingle waste (RAS) can be incorporated into hot-mix asphalt (HMA) pavement mixtures, there is still a lot of waste left over, prompting MnDOT to investigate other potential uses. Alternative options include improving the performance and quality of gravel surfacing and reducing dust by replacing common additives such as calcium chlorides with RAS. This will remove valuable RAS materials from the waste stream, supplement the use of more expensive materials, and improve the performance of local roads.

Aggregate Roads Dust Control: A Brief Synthesis of Current Practices

More than half of our local roadways are gravel roads, making them a vital part of our transportation system. To help control the dust on gravel roads, the Minnesota LRRB has developed a new guidebook, which summarizes a variety dust suppressants, their effectiveness, and impacts.

More than half of our local roadways are gravel roads, making them a vital part of our transportation system. One of the drawbacks and biggest complaints about gravel roads is the dust they produce when vehicles drive over them.  Residents that live on gravel roads deal with the dust that settles on their homes, yards, and parked cars. Dust can also have adverse effects on air quality and the environment. To help control the dust on gravel roads, the Minnesota LRRB has developed this new guidebook, which summarizes a variety dust suppressants, their effectiveness and impacts.

New study to shed light on environmental impacts of deicers

Even naturally derived products like corn syrup and beet juice can impact the environment when applied to salt mixtures for winter roadways.

A wide range of products, including the ones mentioned above, are added to deicing mixes to limit the amount of salt needed for Minnesota roads each winter. However, although information is available about the corrosive properties of various deicing chemicals, less is known about the toxicity of these compounds, especially to the aquatic environment.

Thanks to a recently completed project sponsored by the Clear Roads Pooled Fund, MnDOT winter maintenance personnel will better understand the relative toxicity of eight common deicing agents, which also include non-organics like Magnesium Chloride, Calcium Chloride and Potassium Acetate.

“Because the state has been trying a lot of different alternative chemicals, we wanted to get a better handle on the environmental impacts,” said MnDOT engineer Tom Peters, the technical liaison for the 26-member, Minnesota-led pooled fund for winter maintenance research.

In January, researchers plan to release a concise summary of the toxicity rankings to help winter highway maintenance managers consider both expected levels of service and potential harm to the environment when selecting a deicer.

A Dec. 3 webinar available on the Clear Roads website discusses their findings.

About Clear Roads

Minnesota is the lead state for the Clear Roads Pooled Fund, which conducts rigorous testing of winter maintenance materials, equipment and techniques. Other recent and upcoming research (see our Technical Summary on the program) includes a winter maintenance cost-benefit analysis toolkit, snow removal techniques at extreme temperatures and environmental factors that can cause fatigue in snowplow operators.

You can learn more about Clear Roads via the project’s e-newsletter.

MnDOT, LRRB announce new research projects

Minnesota’s next round of transportation research projects will explore using traffic signal data to predict crashes, evaluate various impacts of bicycling on the state and address a range of other transportation issues.

The state’s two transportation research governing boards have authorized funding for a total of 24 new research projects. MnDOT’s Transportation Research Innovation Group (TRIG) and the Local Road Research Board announced their Fiscal Year 2015 funding awards this week after hearing proposals from researchers in several states. MnDOT Research Management Engineer Hafiz Munir said the projects, which are listed below, reflect the needs of state and local practitioners.

“Many of the projects fall under the ‘traffic and safety’ or ‘materials and construction’ categories, which I think reflects MnDOT and local agency priorities,” Munir said. “Ultimately, all of these research projects address business needs of the people who build and maintain our roads.”

Links are provided to brief descriptions of each project (as provided by the researchers who submitted the proposals).

Environment

Maintenance

Materials and Construction

Multimodal

Policy and Planning

Traffic and Safety