Excalibur and the High Roller may be closed for the season, but Valleyfair Amusement Park still has one attraction open for the season: a driving track for Minnesota snowplow drivers.
MnDOT-funded researchers are studying the effects of weather and vehicle traffic on different deicing treatments in the parking lots of Valleyfair and Canterbury Park in Shakopee, Minn.
It’s been a busy winter, but each week MnDOT Metro District snowplow drivers make one last stop before heading home, to apply different combinations of salt and anti-icing chemicals to nine 1,000-foot driving lanes. They also drive over each lane multiple times to test the effect of traffic.
“We’re running trucks up to 30 miles per hour with different speeds, wind conditions, traffic conditions and pre-wetting chemicals,” said Steve Druschel, a researcher with the Minnesota State University, Mankato. “Each lane is its own experimental unit.”
Professor Druschel’s students will review more than 17,000 photos from time-lapsed cameras to document how the snow melted in each experimental run.
“The influence of factors like pavement type and age, traffic volume, truck proportion, weather conditions and sun presence will be assessed to evaluate which techniques have special advantages for certain situations or roadways,” said Maintenance Research and Training Engineer Tom Peters.
In 2010, Druschel tested 25 anti-icing compounds in 1,500 different combinations in a laboratory to study the effectiveness of different deicers.
“Public work superintendents commented, ‘Great work. It looks good, except it’s all in the lab. Beakers aren’t what people drive on,’ ” Druschel said. “So we’re taking it from the two-inch ice cup to the real world in phase two of this study.”
With rock salt prices quadrupled, finding the most cost-effective methods of treatment is important.
This latest research will help determine the best times for applying anti-icing treatments and examine whether certain chemicals — such as a pre-storm liquid treatment that costs twice as much — melt enough snow to be worth the extra cost.
Test runs in Shakopee are strictly experimental, but in Mankato students are analyzing how real-world salting treatments are working on the North Star Bridge.
An article in the Mankato Free Press tells how Druschel’s team is collecting road melt runoff and documenting bridge traffic. (Big trucks, for instance, squeeze more water out of the snow.)
Students plan to use time-lapsed photos, along with weather data and snowplow records, to determine what chemical treatments worked best – and when.
With the multi-pronged research project, Druschel hopes to put definitiveness to what some snowplow drivers have already tried in the field.
“The key to it is not so much that we’re so smart and we have a better idea or are inventing something new,” he said. “We’re just trying to enhance what they are already doing.”
As a graduate student 35 years ago, Bill Gardner attended his first Transportation Research Board Annual Meeting, and he still remembers the thrill.
“I felt like a kid in a candy shop,” recalled Gardner, who heads MnDOT’s Office of Freight and Commercial Vehicle Operations. “I was amazed at the diversity of topics… You could find people who have devoted their whole lives to the hazards of rural mailboxes.”
Gardner and other MnDOT leaders on Tuesday recounted their experiences from this year’s annual meeting — which drew more than 10,000 participants — and encouraged other MnDOT staff to get involved in the organization, which helps set national transportation guidelines, oversees collaborative research and facilitates the exchange of information.
“We’re heavily involved, but I think we could be more involved,” said Modal Planning and Program Management Director Tim Henkel, who has been part of the TRB for more than 20 years.
Henkel said TRB involvement benefits MnDOT in several ways, including access to national and international experts, the ability to keep tabs on hot-button issues and having a seat at the table in decision-making.
“It makes us a more enlightened and informed decision-making body,” Henkel said.
MnDOT has more than 60 staff serving on 114 TRB committees and contributes $125,000 annually to the TRB core program, gaining $127 in collaborative research for every $1 it contributes.
As part of a series of staff forums they will hold throughout the year, MnDOT leaders chose to highlight the TRB, which met in January. (MnDOT employees interested in attending next year or getting involved in the TRB should speak with their supervisor.)
State Bridge Engineer Nancy Daubenberger, who serves on a TRB subcommittee and gave a presentation at the recent conference, said it helps to hear about the challenges faced by agencies around the country.
Assistant Engineering Services Division Director Amr Jabr, who attended for the first time, said he used a smartphone app just to decide which of the approximately 3,500 sessions he wanted to attend.
“I thought it was an extremely good experience,” he said. “I picked up a lot of information and made a lot of new contacts.”
Each year, approximately 17 percent of road construction work zone fatalities nationwide are pedestrians.
At special risk are the visually impaired, who rely on walking and public transportation to get around.
A major challenge for them is crossing the street — which is even more difficult if an intersection is torn up.
MnDOT has invested significant effort to accommodate pedestrians, particularly those with disabilities, in temporary traffic control situations. This includes requiring temporary curb ramps and alternative routes when a sidewalk is closed.
Researchers, funded by MnDOT, have now developed a cell phone application to guide blind pedestrians around a work-zone.
Building on previous work to provide geometric and signal timing information to visually impaired pedestrians at signalized intersections, the smartphone-based navigation system alerts users to upcoming work zones and describes how to navigate such intersections safely.
The smartphone application uses GPS and Bluetooth technologies to determine a user’s location. Once a work zone is detected, the smartphone vibrates and announces a corresponding audible message. The user can tap the smartphone to repeat the message, if needed.
The federal government strongly encourages states to provide either audible warnings or tactile maps at work zones where visually impaired pedestrians are expected to be impacted.
“The smartphone application is a step in that direction,” said MnDOT technical liaison Ken Johnson. “It’s a way to see if this type of way-finding device would work.”
Since smartphone use is still limited, the state is also interested in special equipment that could relay the audible warnings at affected work zones.
“However, smartphone use is increasing in the general population, as well as with persons with disabilities, and there will likely be a day when it will be rare to not have a smartphone and this tool could meet road agency needs,” Johnson said.
Before developing the smartphone application, researchers surveyed 10 visually impaired people about their experiences at work zones and what types of information would be helpful in bypass or routing instructions.
The University of Minnesota research team, led by Chen-Fu Liao, tested the smartphone application by attaching four Bluetooth beacons to light posts near a construction site in St. Paul.
Additional research is now needed to conduct experiments with visually impaired users and evaluate system reliability and usefulness.
Development of a Navigation System Using Smartphone and Bluetooth Technologies to Help the Visually Impaired Navigate Work Zones Safely — Final Report (PDF, 1 MB, 86 pages)
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.
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.”
There’s broad agreement that the U.S. transportation system cannot continue to be funded with existing financing and revenue-generation methods. What’s unclear, however, is how to pay for highway projects in the future. The current transportation funding system emphasizes user fees, but there is growing interest in alternative funding strategies. One promising strategy is value capture, which aims to recover the value of benefits received by property owners and developers as a result of infrastructure improvements.
In recent years, University of Minnesota researchers have helped lead the way in value capture research with a series of reports identifying value capture strategies. In a newly published study, the research team applied their previous work to a real-world scenario, with impressive results.
The new research, sponsored by the Minnesota Department of Transportation, focused on the planned development of Trunk Highway 610 (TH 610) in Maple Grove, Minnesota—a stretch of planned state highway delayed for years by state transportation funding shortages. Researchers set out to discover how the value of the enhanced accessibility provided by the planned improvements could be predicted and captured to help fund the project’s completion.
To accomplish their goal, researchers first defined a study area of about 10 square miles surrounding the unfinished highway segment. Then, they modeled property values based on five factors using parcel-level data. This model was designed to isolate the so-called “highway premium” by controlling for other factors that affect land value including water views, open space, railroads, transit stops, and existing highway exits. Using this model, researchers found significant evidence that the completion of the highway could lead to an over $17 million increase in property value.
Researchers expect these findings to have significant benefits for the TH 610 project and beyond.
Read the full article in the March issue of Catalyst.
Photo courtesy of SRF Consulting Group, Inc.
Two summers ago, the Minnesota Department of Transportation installed electronic message boards on parts of Interstates 35W and 94 to help warn drivers of crashes and to recommend speed levels during periods of high congestion.
Now, MnDOT would like to use the devices — officially known as Intelligent Lane Control Signs (ILCS) — to advise drivers of sudden stopping or slowing of traffic. Many crashes occur when drivers cannot react quickly enough to these changes.
The Minnesota Traffic Observatory (shown in the feature photo above) is developing a warning system to detect such problematic traffic patterns and issue automatic advisories to drivers.
Shock waves on I-94
A section of I-94 in downtown Minneapolis, where southbound I-35W and westbound I-94 converge, may have the highest crash rate in the state.
As shown in the video above, vehicles constantly slow down and speed up here during rush hour, which causes a ripple effect called “shock waves.”
“There’s a crash every two days,” said University of Minnesota researcher John Hourdos, whose students watched over a year’s worth of video footage to document every accident and near accident. “They’re not severe crashes — no one has died for as long as I can remember, and most happen at slow speeds — but they cause a lot of delays for the traveling public.”
When statistics were still being kept, this section of I-94 had the highest number of accidents in the state, with approximately 150 crashes and 400 near crashes observed in 2003.
Researchers developed a program 10 years ago to detect “shock wave” patterns in the traffic, but they couldn’t develop a practical solution until the state invested in electronic message boards.
The University of Minnesota deployed cameras and sensors on three downtown rooftops in 2002 to observe traffic patterns. They provide seamless coverage of the entire area, allowing researchers to watch vehicles from the moment they enter and exit the area. MnDOT has added additional cameras and detectors to watch over this roadway section. For the past year, the combined efforts of MnDOT and the university have provided data from 26 cameras and 12 traffic sensors for the two-mile section that includes the high-crash frequency location.
Thanks to the message boards, Hourdos and his team can now create an automated system to warn drivers when conditions for “shock waves” are greatest, using an algorithm he developed in the previous study.
A newer problem that researchers hope to tackle is the lineup of cars on I-35W southbound during rush hour at the newly reconstructed Crosstown interchange.
Although two lanes of traffic are provided for eastbound Highway 62 at the I-35W/62 split, these vehicles must later converge into one lane, due to the Portland Avenue exit. This causes a back-up on the 62 ramp that stretches back to 35W.
Hourdos said developing an algorithm to detect these queues is a different problem than what goes on with I-94, since there is a constant stoppage of cars and no rolling shockwaves.
“Combining the two methodologies will form a more robust solution and a single implementable driver warning system,” Hourdos said.
Researchers might target other problems areas should the state install additional ILCS message boards elsewhere in the Twin Cities.
A new guidebook offers Minnesota cities practical advice for making their streets more accessible to all users.
Complete Streets from Policy to Project shares insights and examples from 11 communities across the country, including Albert Lea, Fargo-Moorhead, Hennepin County and Rochester, that have successfully implemented the strategies of Complete Streets — a holistic approach to transportation planning that considers all modes of traffic (rail, transit, pedestrian, motor vehicle, bicycle, etc.).
While many sources offer guidance for implementing Complete Streets, they typically only provide general information or come from an advocacy group stressing one transportation mode or another.
The Minnesota Department of Transportation wanted to collect case studies from practitioners and develop recommendations for best practices that are applicable to the unique circumstances, challenges and opportunities of Minnesota communities.
The book highlights six best practices areas: framing and positioning, institutionalizing, analysis and evaluation, project delivery and construction, promotion and education, and funding.
The research makes it clear that there is no one-size-fits-all approach to Complete Streets that will work for all communities, so any approach must be tailored to a community’s unique challenges and opportunities.
This practitioner-oriented guidebook was co-funded by MnDOT and the Local Road Research Board.
“This was a very important step in building knowledge for MnDOT and other Minnesota entities,” said Scott Bradley, director of MnDOT Context Sensitive Solutions. “It takes us beyond general information that doesn’t necessarily translate to the challenges and opportunities we face in the state.”
Complete Streets from Policy to Project - New (PDF, 19 MB, 156 pages)
Complete Streets Implementation Resource Guide for Minnesota Local Agencies - Released February 2013 (PDF, 17 MB, 54 pages)
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.
Nearly every time a highway or airport expansion is proposed, transportation planners face opposition from residents who fear the increased noise levels in their homes and businesses. Traffic noise is often mitigated with physical noise barriers, but the large, thick walls often draw opposition as well.
A new technology developed by University of Minnesota mechanical engineering professor Rajesh Rajamani as part of a research project funded by the National Science Foundation could soon provide a nearly invisible solution for transportation noise cancellation—and give transportation planners another tool for overcoming project opposition.
Noise enters homes close to airports and highways primarily through windows, and windows can transmit ten times the sound energy as walls can, says Rajamani. With this in mind, researchers set out to reduce the amount of transportation noise transmitted through windows.
To accomplish this goal, researchers created a method of active noise control for windows. Active noise control works by using speakers to generate a sound wave that is a mirror image of the undesirable sound wave. Superimposing an “anti-noise” wave of the same amplitude as the undesirable noise wave results in a reduced decibel level of noise in the environment.
The research team began by designing thin, transparent speaker panels to fit in the empty space between the two panes of a double-pane window. Then, the researchers tested the effectiveness of the new speakers, using them to cancel out undesirable transportation noise from outside the home while preserving the desirable noise from inside the home.
In addition to mitigating traffic noise, this new technology offers other surprising benefits. Researchers have found that the “smart window” speakers can actually be used as home audio speakers without losing any of their noise-control benefits.
Read the full article in the February issue of Catalyst.