Tag Archives: research

New recommendations aim to help roadside turfgrass thrive

Keeping Minnesota’s roadsides green is about more than just aesthetics—healthy turfgrass can improve water quality, reduce erosion and road noise, and provide animal habitat. However, harsh conditions such as heat, drought, and salt use can make it difficult for roadside turfgrass to thrive.

In 2014, as part of a study funded by the Minnesota Local Road Research Board (LRRB), researchers in the University of Minnesota’s Department of Horticultural Science identified a new salt-tolerant turfgrass mixture that could be used on Minnesota roadsides. But, when MnDOT began using the mixture, called MNST-12, the agency experienced a series of installation failures.

Now, led by Professor Eric Watkins, the research team has identified new best management practices for installing and establishing this type of salt-tolerant turfgrass.  The study, funded by the LRRB, specifically focused on watering practices, soil amendments, and planting date for both seed and sod.

“Newer improved seed or sod mixes like MNST-12 may have differing requirements for successful establishment compared to other species or cultivars that contractors and other turf professionals are more familiar with,” Watkins says. “Since all of these management practices are prescribed—or not prescribed—in the MnDOT specifications, generating data that can inform future specifications is a valuable outcome of this work.”

The study, which was conducted over several years, included experiments on how water should be applied to new MNST-12 turfgrass installations, the use of soil amendments at the time of establishment, and the effect of the seeding or sodding date on the success of a new planting.

Researchers tested turfgrass watering requirements using an automated rain-out shelter. Photo: Matt Cavanaugh

Based on their findings, the researchers recommend these changes to MnDOT specifications:

  • No soil amendments are necessary, but adequate seedbed preparation is important.
  • Seeding is preferred to sodding between August 15 and September 15.
  • Sodding can be permitted throughout the year, but only if the installer is able to supply frequent irrigation.
  • When watering in sod, attention should be given to the species being used and local rates of evapotranspiration (evaporation from both the soil and plant leaves). Sod installers can anticipate using between 100,000 and 170,000 gallons of water per acre to ensure a successful establishment.
  • Sod can be mowed as soon as sufficient root growth prevents an operator from manually pulling up pieces by hand, but it should not be mowed if wilting from heat or drought.

Currently, the researchers are using the results of this project to develop methods for educating and training stakeholders, including turfgrass installers, on these best management practices. They are also developing systems that could be used by installers in the field to help maximize the success rate of turfgrass installations.

“These best management practices can help limit installation failures and reduce maintenance inputs for future installations, providing both an economic and environmental benefit,” Watkins says.

“The knowledge and improved specifications we gained through this research will allow us to make our contractors more successful, which makes MnDOT successful,” says Dwayne Stenlund, MnDOT erosion control specialist. Because local agencies often rely on these MnDOT specifications as a guide for their projects, they will also benefit from the improved practices.

Stenlund also says the new specifications—especially those related to watering requirements—could allow for a clearer understanding of the true cost and value of turfgrass installation and maintenance work, which could ultimately improve the accuracy of the project bidding process.

In another project, the research team is exploring other turfgrass stresses, such as ice cover and heat. They are also testing additional turfgrass species and mixtures in an effort to continue improving MnDOT specifications for roadside turfgrass installations.

Developing a Uniform Process for Quantifying Research Benefits

Researchers worked with MnDOT technical experts to develop a method for identifying the financial and other benefits of MnDOT research projects. They developed a seven-step process for quantifying benefits and applied the process to 11 recent MnDOT research projects. Results showed that these projects were yielding significant financial benefits.

“We have very high expectations for the research dollars we spend,” said Hafiz Munir, Research Management Engineer. “MnDOT Research Services & Library. Following this project, we now ask investigators to tell us upfront what benefits their research could achieve, and we have improved our internal process for tracking and assessing the quantifiable benefits.”

“A lack of before-research data on the transportation activities being studied may be the biggest challenge to quantifying the benefits of research on Minnesota transportation needs. Other states are also trying to do this, but they use informal or ad hoc processes,” said Howard Preston, Senior Transportation Engineer, CH2M Hill.

What Was the Need?

MnDOT Research Services & Library manages more than $10 million in research each year, with 230 active projects covering everything transportation-related — from subgrade soils to driver psychology. Communicating the value of these research investments is an important component of transparency in government, a core interest in Minnesota.

Quantifying the benefits of research projects that lead to innovations such as new and improved materials, methods and specifications is important to MnDOT and its customers. However, because MnDOT conducts such a wide variety of research projects, it is challenging to assess the benefits that will, when applied in practice, result in quantifiable savings of time, materials or labor, or that will lead to safer roads and fewer traffic crashes.

What Was Our Goal?

MnDOT undertook this project to develop a more systematic method for identifying and measuring the financial and other benefits of its research in relation to the costs. The goal was to develop an accessible, easily applicable process that could be pilot-tested on a selection of MnDOT research projects from recent years.

What Did We Do?

MnDOT provided researchers with documents about benefits quantification practices to review and with the results of a survey of state departments of transportation on their approaches to quantifying research benefits. This review identified few states that had developed formal guidelines for assessing research benefits, and none were easily applicable to MnDOT procedures.

After reviewing the findings and consulting with MnDOT technical experts, investigators recognized that any procedure for quantifying benefits should be rooted in current MnDOT research processes. Researchers worked with a number of MnDOT offices to identify research projects that were suitable for assessing financial and other benefits from research results.

In addition to identifying projects for benefits analysis, investigators and MnDOT identified categories of benefits and developed a seven-step process for gathering and organizing cost data for various project types, applying a benefits assessment process and comparing benefits to research cost.

What Did We Learn?

The research team performed benefit-cost assessments for 11 projects. Six of the assessments had high confidence levels. One challenge in developing a uniform process included refining the complex range of cost input categories, input data options and research objectives associated with the research projects. Assembling and organizing before-research data, even for fairly simple maintenance activities, proved particularly challenging and impeded the development of benefits assessment processes.

Investigators developed a user guide, a training presentation and a quantification tool — a complex set of spreadsheets for inputting data and calculating comparative benefits. The quantification tool should eventually develop into a user-friendly software package or Web interface.

SAFL baffle
The SAFL baffle was developed in a MnDOT research project for $257,000. Researchers determined that its use across Minnesota would save taxpayers $8.5 million over three years.

Based on the analysis of cost and savings data, the 11 research projects showed significant benefits. In one 2012 project, investigators developed an inexpensive baffle that is inserted into stormwater sumps and slows the flow of water in and out, allowing more contaminated sediment to settle rather than being carried into streams and lakes. Re-search to develop the baffle, at the University of Minnesota St. Anthony Falls Laboratory (SAFL), cost $257,000. The cost to purchase and install the baffle is about $4,000 in Minnesota compared to $25,000 for more traditional stormwater mitigation solutions. Use of SAFL baffles in Minnesota is projected to save the state about $8.5 million in equipment, installation and environmental costs over a three-year period.

In total, the research cost of $1.98 million for the 11 projects analyzed is expected to save an estimated $68.6 million for MnDOT and Minnesota cities and counties over a three-year period, for a benefit-to-cost ratio of about 34-to-1. The expected savings will be enough to pay for the research budget for six or seven years.

What’s Next?

MnDOT has added quantification-of-benefits elements to its research proposal evaluation process, and since late 2015 has asked potential principal investigators to supply information on the current costs of the activities they propose to study and improve.

Since 2016, research project awards have included a request that investigators develop quantifiable data resulting from their research activity. The awards offer additional funds for that work. Investigators now provide a brief memorandum within the first 90 days of the project describing how they will quantify benefits, and in some cases presenting preliminary data. At the end of the project, these investigators describe their quantification process and results. MnDOT has tracked this information in a database, finding that about three out of every four projects show potential to yield quantifiable benefits.


This post pertains to Report 2017-13, “Development of a Process for Quantifying the Benefits of Research,” published July 2017. 

Seven Pilot Projects to Change Transportation Practice in Minnesota

Roadside fencing that protects endangered turtles, a toolkit for identifying potentially acid-producing rock and a device that could save MnDOT $200 million a year in pavement damage are just a few of the advancements that MnDOT hopes to make in the near future, thanks to seven recently funded research implementation projects.

Each spring, the governing board for MnDOT’s research program funds initiatives that help put new technology or research advances into practice. This year’s picks aim to improve the environment, reporting of traffic signal data, notification of lane closures and the design and quality of pavements.

Here’s a brief look at the projects (full proposals here):

Protecting the Environment and Wildlife

  • To avoid the leaching of potentially acid-generating rock during excavation projects, MnDOT hopes to develop a GIS-based risk-screening tool that identifies areas where PAG rock might be encountered. Guidance will be developed for identifying and handling PAG rock.

Found in bedrock throughout the state – especially northern Minnesota, PAG minerals can release acid upon contact with air or water, a danger to aquatic and human life.

“Anytime we dig, there is the potential to expose this stuff,” said Jason Richter, chief geologist.

  • Reducing roadway access for small animals, including endangered turtles, is a priority for MnDOT and the Minnesota Department of Resources. MnDOT will analyze the effectiveness of different types of small animal exclusion fences tried across the state and develop a standard set of designs for future projects.
Improved Reporting of Traffic Signal Data
  • A centralized hub of traffic signal data could benefit future vehicle-to-infrastructure (V2I) applications and assist with the modeling of transportation project impacts. Methods and tools will be developed for a regional database of intersection control information that extracts data from MnDOT’s recently acquired Central Traffic Signal Control System and soon-to-be adopted Signal Performance Measure application.
Real-Time Notice of Lane Closures
  • In this pilot project, 20 MnDOT arrow board messages will be equipped with technology that automatically reports lane closures on 511 and highway message boards, providing more timely motorist notification.
Longer-Lasting Roads and Improved Quality Control
  • This summer, a new quality assurance device called the Rolling Density Meter will be deployed on several pavement projects, eliminating the need for destructive sample cores.
    “This is the ultimate in compaction control,” said Glenn Engstrom, Office of Materials and Road Research director. If contractors obtain the right level of density when paving asphalt roads, MnDOT could eliminate $200 million per year in premature road failure.
  • In 2018, MnDOT plans to require Intelligent Compaction (a pavement roller technology that reduces workmanship issues) on all significant asphalt projects. A vehicle-mounted mobile imaging device will be piloted that collects necessary supportive roadway alignment data, without the need for survey crews.
  • Upgrades to MnDOT’s pavement design software, MnPAVE, (incorporating recycled unbound and conventional base material properties) will help increase the service life of Minnesota roads.

I-35W ‘Smart Bridge’ Test Site Uses Vibration Data to Detect Bridge Defects

By analyzing vibration data from the I-35W St. Anthony Falls Bridge, MnDOT is working to develop monitoring systems that could detect structural defects early on and ultimately allow engineers to improve bridge designs.

“With data spanning several years, the I-35W St. Anthony Falls Bridge offers a unique opportunity for investigating the environmental effects on a new concrete bridge in a location with weather extremes,” said Lauren Linderman, Assistant Professor, University of Minnesota Department of Civil, Environmental and Geo-Engineering. Linderman served as the research project’s principal investigator.

“This project gets MnDOT closer to using bridge monitoring systems in combination with visual inspection to help detect structural problems before they affect safety or require expensive repairs,” said Benjamin Jilk, Principal Engineer, MnDOT Bridge Office. Jilk served as the research project’s technical liaison.

2017-01-bridge.png
Completed in 2008, the I-35W St. Anthony Falls Bridge has a smart bridge monitoring system that includes hundreds of sensors.

What Was the Need?

In September 2008, the I-35W St. Anthony Falls Bridge was constructed to include a “smart bridge” electronic monitoring system. This system includes more than 500 sensors that continuously provide data on how the concrete structure bends and deforms in response to traffic loads, wind and temperature changes. Transportation agencies are increasingly interested in such systems. As a complement to regular inspections, they can help detect problems early on, before the problems require expensive repairs or lead to catastrophic failure. Smart bridge systems can also help engineers improve future bridge designs.

The smart bridge system on the I-35W St. Anthony Falls Bridge includes accelerometers, which provide data on the way the bridge vibrates in response to various stimuli, including structural damage. Vibration-based monitoring has the advantage of allowing damage to be detected at any location within the bridge rather than only at the specific locations where measuring devices have been placed.

However, it can be difficult to use vibration monitoring to detect damage when vibration is masked by the bridge’s natural response to traffic loads, wind, temperature changes and other environmental conditions. A crack in a bridge girder, for example, can produce a vibration signature similar to one produced by a change in beam length due to variations in temperature or other causes. Consequently, since 2008 MnDOT has conducted a series of projects using data from the St. Anthony Falls Bridge to establish a way to distinguish anomalous data indicating a structural defect or damage from background “noise” associated with other causes.

What Was Our Goal?

This project sought to develop a method for analyzing accelerometer data from the I-35W St. Anthony Falls Bridge that would show how the bridge naturally vibrates due to traffic, wind and other environmental conditions. With this fingerprint of the bridge’s natural vibration, engineers would have a baseline against which to measure anomalies in the data that might indicate structural damage.

What Did We Do?

A large amount of data has been collected from the bridge since its construction. To establish the vibratory fingerprint for the bridge, researchers examined the frequencies and shapes (or modes) of bridge vibration waves. The method they used to identify the data segments needed for the fingerprint was to evaluate the peak amplitude of bridge vibration waves and their root mean square (RMS), a measure of the intensity of free vibration.

The researchers applied this method to the vibration data collected on the I-35W St. Anthony Falls Bridge between April 2010 and July 2015, calculating the average frequencies for four wave modes and determining how they varied with the bridge’s temperature. They also calculated the way frequencies changed with the bridge’s thermal gradients, or variations in temperature between parts of the structure.

What Did We Learn?

The methods developed in this project were successful in establishing a fingerprint for the way the I-35W St. Anthony Falls Bridge vibrates due to environmental conditions, and a way to evaluate changes in vibration over time indicative of structural damage or other factors.

Researchers found that the ratio of peak signal amplitude to RMS in bridge vibrations was a strong indicator of data that should be analyzed, and was evidence of a large excitation followed by free vibration. By themselves, peak amplitude and RMS cannot distinguish between ambient free vibration and forced vibration.

Researchers were able to use this method to successfully analyze 29,333 data segments from the I-35W St. Anthony Falls Bridge. This analysis revealed that as temperature increases, the natural frequency of vibration tends to decrease. The magnitude of this change, they concluded, must be related not just to the elasticity of the bridge but also to other factors such as humidity. However, temperature gradients within the bridge did not appear to have a significant effect on the natural frequencies of the structure.

What’s Next?

MnDOT will continue to collect data from the bridge as it ages to further understand its behavior. This will provide an opportunity to determine how anomalies in vibration data correspond to cracking and other forms of structural distress. Ultimately, MnDOT hopes to use this bridge monitoring system in combination with visual inspection both to detect problems in bridges earlier and to develop better bridge designs. Researchers are also currently working on a follow-up project, Displacement Monitoring of I-35W Bridge with Current Vibration-Based System, to determine the effects of temperature on the bridge’s dynamic and long-term vertical displacements, which can be used to monitor the bridge’s stiffness, connections and foundations.

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This post pertains to Report 2017-01, Feasibility of Vibration-Based Long-Term Bridge Monitoring Using the I-35W St. Anthony Falls Bridge, published January 2017. 

Newly funded studies tackle big transportation questions

Can Twin Cities roadsides be used to grow habitat for endangered bumble bees? Are unseen factors affecting safety at rural intersectionsHow should Minnesota transportation agencies be preparing for connected vehicle technology?

Minnesota’s next round of transportation research projects will attempt to solve these and other questions facing the state’s transportation community. The Transportation Research and Investment Group, which governs MnDOT’s research program, and the Minnesota Local Road Research Board, which represents cities and counties, recently met and selected 21 transportation research projects for funding in fiscal year 2018.

A couple of MnDOT’s most interesting projects will evaluate the reuse of wastewater at safety rest areas and truck stations and develop a system to optimize the location of 80 truck stations due for replacement in the next 20 years. MnDOT will also partner with the Local Road Research Board to evaluate the use of personal warning sensors for road construction workers.

In addition to the problem of stripping underneath sealcoats on some city streets, other top research projects for local governments involve pedestrian safety enforcement and investigating whether rural, low-volume roads should be treated differently than urban roads for stormwater runoff. Current regulations govern runoff the same, regardless of daily vehicle count or surrounding land use.

“The selected research studies, which typically take one to three years to complete, will address some of the most major policy, environmental and maintenance dilemmas facing transportation practitioners,” said Linda Taylor, director of MnDOT Research Services & Library.

Below is a list of the selected projects, with links to associated need statements. Final project scopes will become available once contracts are approved. For further information, go here.

Bridges & Structures

Materials & Construction

Environmental

Planning

Maintenance Operations

Traffic & Safety 

MnDOT shares knowledge at national research conference

MnDOT employees are sharing knowledge and displaying leadership in Washington this week by delivering presentations and conducting meetings at the nation’s preeminent transportation conference.

trbThe Transportation Research Board (TRB) 96th Annual Meeting held Jan. 8-12 at the Walter E. Washington Convention Center in Washington, D.C., is expected to draw more than 12,000 transportation professionals from around the world. According to its website, the 2017 event scheduled more than 5,000 presentations in more than 800 sessions and workshops addressing topics of interest to policy makers, administrators, practitioners, researchers, and representatives of government, industry, and academic institutions. TRB’s 2017 annual meeting theme is “Transportation Innovation: Leading the Way in an Era of Rapid Change.”

“Every year when TRB holds its annual meeting, MnDOT’s strong presence at the event is a reminder of our state’s commitment to top-notch transportation research,” said Linda Taylor, director of MnDOT Research Services and Library.

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Brad Larsen (left), MnPASS Policy and Planning Program Director, speaks with a conference attendee during a poster session this week at the Transportation Research Board Annual Meeting in Washington, D.C. Larsen was one of two dozen MnDOT employees invited to deliver presentations at the national transportation research event.

The following is a roundup of MnDOT employees who were invited to deliver presentations and participate in key committee meetings along with their presentation topics and committees (not all staff may have attended the conference; however, due to limited funding or availability):

Kenneth Buckeye, Financial Management

Thomas Burnham, Materials & Road Research

Kathryn Caskey, Transportation System Management

Shongtao Dai, Materials & Road Research

Dan Franta, District 7

Timothy Henkel, Modal Planning & Program Management 

Kyle Hoegh, Materials & Road Research

 Bruce Holdhusen, Transportation System Management

 Santiago Huerta, Metro District

Bernard Izevbekhai, Materials & Road Research

Brad Larsen, Metro District

Rita Lederle, Bridges

Francis Loetterle, Passenger Rail

Dean Mikulik, Materials & Road Research (student worker)

Mark Nelson, Transportation System Management

Steven Olson, Materials & Road Research

David Solsrud, Modal Planning & Program Management 

Trisha Stefanski, Modal Planning & Program Management 

Joel Ulring, State Aid for Local Transportation

Jennifer Wells, Bridges

Benjamin Worel, Materials & Road Research

Charles Zelle, Commissioner

Knowing While Mowing: GPS Keeps Maintenance Workers Out Of the Weeds

As temperatures fall and days get shorter, MnDOT Metro District maintenance workers are wrapping up a season of mowing grass along roadsides and in medians that they hope will prove a little more efficient than in the past.

Thanks to a research project that installed GPS devices in tractor cabs, operators have a better sense of exactly which areas they need to mow and which areas should be left alone. Five Metro District tractors were tested in 2015. This year, more than 40 tractors were fitted with the automated vehicle location (AVL) technology, which includes a GPS antenna, an on-board central processing unit (CPU) and an in-cab screen with a user interface.

Trisha Stefanski, Metro District asset management engineer, expects one of the biggest benefits of the project to be a reduction in herbicide use. Maintenance crews use herbicide to control the spread of noxious weeds that sometimes get spread during mowing operations. Mapping exactly where noxious weeds are, and providing that information to operators on a real-time, in-cab screen and user interface helps them mow around those areas.

“We’re really hoping it will reduce the amount of herbicide that we’re putting on our roadways by 50 percent,” Stefanski said. “We’re not certain that will be the number, but that’s what we’re hoping for. We think just not mowing those areas will not spread as many noxious weeds and so we don’t have to apply as much herbicide.”

Metro District operators, such as Jesse Lopez, give the AVL technology rave reviews.

“Basically you can see what you shouldn’t mow and what you should mow. So, it makes it easy for me. It’s just like playing a game,” Lopez said. “This actually helps me to optimize what my job is. I know exactly where I’m at and where I’m going. I think everyone should use it – absolutely everybody who is in a mowing situation or a plowing situation.”

In addition, the AVL technology helps maintenance supervisors keep tabs on exactly where their operators are in real time. It also helps supervisors complete reports by automatically providing the geographic areas where mowing has been completed.

Stefanski says the project has gone really well, and she hopes collecting more data over another mowing season will show real savings on herbicide use. In the meantime, she is thinking of other ways AVL technology could be applied to maintenance operations.

“What I really like about the project is that we are taking something used in a lot snow plows and a lot of other technologies – cars, other things, maybe UPS uses them – and we’re putting it into maintenance operations,” Stefanski said. “Having it for mowing, we can also use it for smooth pavements. We can also use it for other things in mowing operations.”

CTS Research Conference: a day of discovery and innovation

Have you registered to attend the annual CTS Transportation Research Conference on November 3?

The one-day event, held at The Commons Hotel on the U of M campus, will highlight new learning, emerging ideas, and the latest innovations in transportation. Sessions will also explore implementation efforts and engagement activities.

In the opening session, “Creating Sustainable, Livable, Forward-Compatible Cities for Economic Resilience,” author Gabe Klein will explore the innovations taking place in cities and how government, business, and nonprofit leaders can utilize this wave of change to shape a quality of life that is improved and not compromised.

Following his presentation, the following panel of experts will share perspectives on the implications for the future of transportation systems in Minnesota cities:

  • Mayor Ardell Brede, City of Rochester
  • Mayor Chris Coleman, City of St. Paul
  • Anu Ramaswami, Professor, Humphrey School of Public Affairs, University of Minnesota
  • Mayor Betsy Hodges, City of Minneapolis (invited)

In the luncheon presentation, “How to Promote and Prepare for Automated Driving,” Professor Byrant Walker Smith will present steps that governments can take now to encourage the development, deployment, and use of automated driving systems.

Complete program details and registration information is available on the CTS website. Please plan to join us for a day of discovery and innovation!

Drone Project Earns State Government Innovation Award

The MnDOT Office of Aeronautics and Aviation was recognized last month for the drone research project that also involved the Office of Bridge and Structures and MnDOT Research Services.

The Humphrey School of Public Affairs, in partnership with the Bush Foundation, presented a State Government Innovation Award to recognize great work and to encourage an environment that allows agencies to deliver better government services to Minnesotans through creativity, collaboration and efficiency.

The project, titled Unmanned Aircraft Systems (UAV) Bridge Inspection Demonstration Project, found that using drones for bridge inspections improves safety, lessens traffic disruption and reduces work time. For one type of bridge, inspection time shrank from eight days to five.

In the video, Jennifer Zink, MnDOT state bridge inspection engineer, explains the project, along with Tara Kalar, MnDOT associate legal counsel; Cassandra Isackson, director of MnDOT Aeronautics; and Bruce Holdhusen, MnDOT Research program engineer.

The initial drone project drew significant media coverage and a lot of attention from other state departments of transportation from all over the country.

A second phase of the project was approved year and is currently underway. A third phase is already in the planning stages.

More information

New video: Finding solutions to save lives

See how researchers at the Roadway Safety Institute (RSI), led by the University of Minnesota, are working to reduce crashes and save lives on our nation’s roadways in a new video.

The video features RSI director Max Donath and researchers from across the region who are working on a breadth of projects, ranging from reducing crashes at rail grade crossings to improving road safety on tribal lands. The video also highlights a few of RSI’s education efforts, including a museum exhibit designed to introduce preteens to safety concepts.

RSI was established as the Region 5 University Transportation Center in 2013 and is housed at CTS. MnDOT is a key partner for RSI, funding a variety of safety-focused projects by RSI researchers.

For more information about RSI, visit the Institute’s website.