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.
Developing the guidance needed to begin using drones for bridge inspections statewide is among the Minnesota Department of Transportation’s latest batch of research implementation projects.
Project champions take previously proven concepts and help MnDOT turn them into useful practices and procedures to make the state’s transportation system better. Funds can be used for equipment, consultant services or researcher assistance.
“The research implementation program fills the gap between research and deployment of new methods, materials and equipment,” Bruce Holdhusen, MnDOT Research Services senior engineer, said.
Here are the 12 newly funded research implementation projects by category:
Bridge and Structures
Improving Quality of Bridge Inspections Using Unmanned Aircraft Systems (UAS)
Prestressed Concrete Beam Shear Rating
OmniScan Phased Array Ultrasonic Corrosion Imaging System
Environmental
MnDOT Slope Vulnerability Assessments
Maintenance Operations
Ultra-thin Bonded Wearing Course (UTBWC) Snow and Ice and Wind Effects
Materials and Construction
Cold In-Place Recycling (CIR) for Bituminous Over Concrete (BOC)
Geogrid Specification for Aggregate Base Reinforcement
Balanced Design of Asphalt Mixtures
Cone Penetration Testing (CPT) Design Manual for State Geotechnical Engineers
Policy and Planning
One-year Pilot Test and Evaluation of ASTM DOT Package Compass Portal
Traffic and Safety
Improve Traffic Volume Estimates from Regional Transportation Management Center (RTMC)
Understanding Pedestrian Travel Behavior and Safety in Rural Settings
When it comes to creating the transportation system of the future, MnDOT is already doing its research and laying the groundwork for great things to come.
James Benham, JB Knowledge, speaks at the Transportation Conference. (Photo by Rich Kemp)
Among the topics Benham cited in his talk were the Internet of Transportation, unmanned aerial vehicles (drones) and 3-D printing, which MnDOT is already studying or even using.
Internet of Transportation
MnDOT recently produced series of white papers on technological trends that could impact transportation infrastructure in Minnesota.
Google is one of many companies developing autonomous vehicle technology that researchers believe will make driving nearly extinct by 2040. (Photo courtesy of Google)
The report details how the transportation system can accommodate such imminent innovations as autonomous vehicles, mobile web services, mobility as a service, information and communication advances, infrastructure sensors and energy and fuel alternatives.
For example, researchers predict that driving faces near-extinction by 2040, when non-autonomous vehicles will no longer be allowed on public roads at most times. As a result, total transportation-related fatalities may drop 90 percent, road geometry, sightlines and other design priorities may shift, and capacity and speed limits will likely increase on most major roadways.
Unmanned Aerial Vehicles (Drones)
MnDOT is researching how data and images collected by drones could aid bridge inspectors.
When it comes to drones, MnDOT is already conducting important research that the rest of the nation is closely following. Tara Kalar and Jennifer Zink from MnDOT, and Barritt Lovelace of Collins Engineers, spoke about their efforts at last month’s conference.
Last year, MnDOT Research Services published a report titled “Unmanned Aerial Vehicle (UAV) Bridge Inspection Demonstration Project” that detailed how MnDOT could use drones to perform bridge inspection functions. The initial research project tested one drone’s capability in a variety of bridge inspection scenarios last summer at four Minnesota bridges.
In November, researchers conducted a second research phase to test a more specialized drone at the Blatnik Bridge in Duluth that coincided with that bridge’s regularly scheduled inspection.
A few weeks ago, researchers secured funding to conduct a research implementation project that aims “to implement a statewide UAS (unmanned aircraft systems) bridge inspection contract, which will identify overall cost effectiveness, improvements in quality and safety, and future funding sources for both state and local bridges,” according to the project proposal.
3-D Printing
Benham’s talk also addressed 3-D printing, which Chad Hanson, a District 6 project manager, has already used successfully.
Hanson spoke at the conference about his experience using 3-D printing to create a model of the Red Wing Bridge project that brought the project idea to life. According to Hanson, the model enhanced public engagement and informed preliminary design efforts for the bridge.
Chad Hanson, District 6 engineer, used 3-D-printing to create a model of the Red Wing Bridge that was used during the project’s public engagement events. (Photo by Mike Dougherty)
Partners, stakeholders and members of the public could see, touch and hold the 3-D printed models, which accentuated the project’s engagement process.
To mark Earth Day 2016, MnDOT Research Services is taking a glance at five stellar examples of current research projects at MnDOT that involve pollution control, wetland mitigation, road salt reduction and new ways of recycling pavement.
Temporary stormwater ponds with floating head skimmers can remove clean water from the surface of a settling pond.
Soil carried away in stormwater runoff from road construction sites can pollute lakes and rivers.
Stormwater settling ponds provide a place for this sediment to settle before the water is discharged into local bodies of water. However, since stormwater ponds have limited space, a mechanism is needed to remove clean water from the pond to prevent the overflow of sediment-laden water.
MnDOT-funded researchers designed temporary stormwater ponds with floating head skimmers that can remove clean water from the surface of the settling pond, using gravity to discharge water into a ditch or receiving body.
The study, which was completed in spring 2014, identified five methods for “skimming” stormwater ponds that can improve a pond’s effectiveness by 10 percent. MnDOT researchers also created designs for temporary stormwater ponds on construction sites with the capacity to remove approximately 80 percent of suspended solids.
These designs will help contractors meet federal requirements for stormwater pond dewatering. Researchers also determined how often a pond’s deadpool must be cleaned, based on watershed size and pool dimensions.
Stormwater infiltration rates at five swales were significantly better than expected based on published rates.
Stormwater can pick up chemicals and sediments that pollute rivers and streams. Roadside drainage ditches, also known as swales, lessen this effect by absorbing water. But until recently, MnDOT didn’t know how to quantify this effect and incorporate it into pollution control mitigation measures.
In a study completed in fall 2014, researchers evaluated five Minnesota swales, measuring how well water flows through soil at up to 20 locations within each swale.
A key finding: grassed swales are significantly better at absorbing water than expected, which may reduce the need for other, more expensive stormwater management practices, such as ponds or infiltration basins.
This could save MnDOT and counties significant right-of-way and construction costs currently expended on more expensive stormwater management techniques.
Even with little or no road salt, a permeable pavement like this porous asphalt in Robbinsdale, Minnesota, collects little slush and snow in the winter because it warms well and remains porous enough to infiltrate surface water effectively.
Road salt is used for de-icing roadways during winter months, but can have a negative impact on the environment.
This research, which was just approved for funding through the Minnesota Local Road Research Board in December 2015, will investigate the reduction in road salt application during winter months that can be attained with permeable pavements, while still providing for acceptable road safety.
Some initial investigations (see previous study) suggest that road salt application can be substantially reduced, even eliminated, with permeable pavement systems. The proposed research will investigate this hypothesis more thoroughly, and further document the reduction in road salt application that can be expected with permeable pavement.
This photo from spring 2015 shows that wetlands have begun to take hold along Highway 53.
Road construction in northeast Minnesota often causes wetland impacts that require expensive mitigation. However, borrow areas excavated for road construction material can be developed into wetland mitigation sites if hydric vegetation, hydric soils and adequate hydrology are provided. Fourteen wetland mitigation sites were constructed north of Virginia, Minnesota along the U.S. Trunk Highway 53 reconstruction project corridor and evaluated for wetland. The sites were established with the goal of mitigating for project impacts to seasonally flooded basin, fresh meadow, shallow marsh, shrub swamp, wooded swamp, and bog wetlands. All but one of the sites consistently meet wetland hydrology criteria.
The sites contain a variety of plant communities dominated by wet meadow, sedge meadow, and shallow marsh. Floristic Quality Assessment (FQA) condition categories for the sites range from “Poor” to “Exceptional.”
According to the research report published in March 2016, these sites have shown the potential for creating mitigation wetlands in abandoned borrow pits in conjunction with highway construction. Adaptive management, particularly water level regulation, early invasive species control, tree planting, and continued long-term annual monitoring can make mitigation sites like these successful options for wetland mitigation credit.
This photo shows a cold in-place recycling equipment train in action.
MnDOT already extends the lives of some old concrete highways by paving over them with asphalt instead of tearing them up. Now MnDOT hopes to add a third life for these old concrete roads by using a process called cold in-place recycling to re-use that existing asphalt pavement when it reaches the end of its life.
Cold in-place recycling (CIR) uses existing pavements, without heat, to create a new layer of pavement. It involves the same process of cold- central plant mix recycling (which is being employed by MnDOT for the first time on two shoulder repair projects this year), but it is done on the road itself by a train of equipment. It literally recycles an old road while making a new road.
CIR has been in use in Minnesota for 20 years, but only with hot-mix asphalt (HMA) over gravel roads. The purpose of a new study, which was approved for funding in April 2016, is to validate Iowa’s promising new practice using CIR on bituminous over concrete.
In this research project (see proposal), MnDOT will use cold-in-place recycling to replace the asphalt pavement on a concrete road and then evaluate it for several years, comparing it also with control sections.
Along with the potential of a better service life, the cost of CIR is much lower than new hot mix asphalt (HMA). Therefore, a 20-percent to 30-percent price reduction per project may be realized.
Darryl Oeltjenbruns, snowplow driver in District 7, operates the only driver assist system, or DAS, equipped snowplow in the state. The system helps snowplow operators see road alignments and features such as turn lanes, guardrails and road markings. (Photo by Chase Fester)
By Sue Roe, MnDOT Communications
Southwest Minnesota has the highest average wind speeds in the state—bad news for MnDOT snowplow operators who often drive in low visibility to clear roads.
“We have more days when the wind blows than when it doesn’t,” said Chase Fester, MnDOT District 7 transportation operations supervisor. “We struggle with the wind.”
That’s why District 7 is piloting a snowplow driver-assist system (DAS) developed by University of Minnesota researchers to combat the blowing snow and fog that often cause zero visibility. The DAS helps snowplow operators see the road alignment and features, such as turn lanes, guardrails, and road markings. Even in less extreme winter weather, snowplow operators gain assurance of their lane location using the system.
The driver assist system displays a white box on the screen when an obstacle, or in this case a mailbox, is located. If the object appears in the lane, such as a car stuck in a snow drift, the box turns red and gets bigger as the snowplow gets closer to the object. (Photo courtesy of MnDOT District 7)
The DAS was developed and refined over the past 20 years under multiple research projects funded by MnDOT and the USDOT’s University Transportation Center program. Professor Max Donath, director of the University of Minnesota’s Roadway Safety Institute, led the work. In addition to plows, the DAS technology has also been applied in other specialty vehicles such as patrol cars and ambulances. Numerous vehicles using the system have been deployed in both Minnesota and Alaska.
The DAS uses GPS technology and a front-mounted radar to provide an image of the road and any obstacles in front of the operator. The image is displayed on a monitor inside the cab of the plow. The system also vibrates the operator’s seat as a warning if the plow veers too close to the roadway’s centerline or fog line.
“If the driver gets within one foot of the fog line on the right side, the right side of the seat vibrates. If the driver gets too close to the centerline on the left side, the left side vibrates,” said Fester.
The vibrations continue until the driver moves back into the center of the lane. The driver can also turn off the warning feature to clear snow from the shoulder.
The DAS is currently installed in one truck in District 7. The $75,000 cost makes it difficult to install in every truck in the district or the state, although having at least one system in every district may be possible, Fester said.
Fester said the system proved its worth one day in February when blizzard conditions caused zero visibility and forced many road closures in southwest Minnesota. He was called out at 2 a.m. Feb. 8 to assist a stranded state trooper and several motorists on a 12-mile stretch of Hwy 60 between Windom and Heron Lake. Fester drove a pickup behind the DAS-equipped snowplow, driven by Darryl Oeltjenbruns, to reach them.
As the DAS identified stranded vehicles on the way to Heron Lake, Fester and Oeltjenbruns checked to make sure they weren’t occupied with people. Once they made it to Heron Lake, they stopped at the community center, where the state trooper and the stranded motorists he brought in were located.
On the way back to Windom, Fester and the state patrolman continued to check on stranded vehicles as the DAS-equipped snowplow led the way. If the vehicles weren’t in the ditch, motorists drove behind the two MnDOT vehicles. If their vehicles were in the ditch, motorists rode in a Suburban that was also being escorted to Windom. After returning to Windom, the motorists were dropped off at motels or truck stops.
“When we first went out, there were about six stranded vehicles. Coming back from Heron Lake, there were about 15,” Fester said. “At one time, we had 12 vehicles in line as we drove back to Windom, driving about 10 to 15 miles per hour.”
Later that morning the DAS system was used again to locate other motorists.
“We continued to use it until about 10 a.m. or 11 a.m. that day,” Fester said. “The system worked great and kept everyone safe. It was an interesting morning.”
(Reprinted and adapted with permission from an article by Sue Roe in MnDOT’s Feb. 17, 2016 Newsline.)
MnDOT is testing a mobile road condition monitor that uses infrared technology to detect hazardous ice, snow or wet conditions without even touching the pavement.
Maintenance crews hope the device, called the High Sierra Surface Sentinel, could help them better determine when it’s time to apply salt when they’re plowing. The mobile sensor reports air temperature, surface temperature and road friction data.
“The biggest reason we’re looking at this is for the friction reading,” said MnDOT Salt Solutions Coordinator Joe Huneke. “Typically, when operators are patrolling their route and the road looks like it’s getting icy, they’ll err on the side of caution and apply salt — and it may not need it.”
The device being tested by snow and ice crews in northern Minnesota would also provide real-time surface weather conditions. Currently, plow operators and supervisors must enter road conditions into a computer or relay them by phone, a time-consuming process that operators are not always able to perform in a timely manner.
The biggest potential benefit, however, is lower salt consumption.
“Sometimes you get a light cold snow event where it might look like there’s a little ice on the road, but, in fact, you have good friction numbers and you don’t need salt. Once you put chemical down, you’re committed to it,” Huneke said.
District 1 snow and ice crews are evaluating the unit pictured below for its accuracy and effectiveness in determining slippery conditions. It will be compared with another device tested in District 3 that also uses infrared technology to determine how slippery the road is, and technology being tested in District 6 that uses gravitational force to determine the road surface friction.
MnDOT it testing this mobile road condition sensor, which provides real-time surface weather condition of roadways.
Related Research
MnDOT’s Office of Maintenance has its own research program designed to let maintenance personnel test innovative ideas to keep our roads smooth, snow-free and safe. They even put out a monthly bulletin featuring new ideas and technologies. (You can find the back issues here.)
Results of a newly released MnDOT research report shed new light on the role transportation plays in our state’s economic competitiveness, and highlight the unique challenges faced by some of the state’s major industry clusters.
The report, authored by Professor Lee Munnich of the University of Minnesota’s Humphrey School of Public Affairs, underscores the importance of a reliable transportation system in facilitating economic growth. Munnich examined the impact of transportation on Minnesota’s competitive industry clusters — geographically concentrated, interconnected groups of companies and institutions that share knowledge networks, supply chains and specialized labor pools.
MnDOT Research Project Engineer Bruce Holdhusen said MnDOT’s goal with the study was to discover how its investment decisions could help support job creation and economic prosperity.
“The idea is to look at the companies and industries that are already bringing money into the state, figure out what their transportation challenges are, and then use that information to see what kind of investments we could make to support their continued growth,” Holdhusen said.
MnDOT is incorporating the results of the study into its statewide freight planning. The industry clusters-approach also is being used by MnDOT in a statewide effort to talk with manufacturers, other shippers, and carriers about their transportation priorities and challenges. MnDOT will focus on its Metro District starting this summer. Two similar projects have been undertaken in Greater Minnesota, with a third study starting later this year. (Results from one study, in southwest Minnesota/District 8, are available online.)
The full report is available online, and examines a wide range of industries, including forest products, medical devices, robotics and processed foods. We’ve pulled out a few interesting tidbits below.
Recreational Vehicles (Northwest Minnesota)
Minnesota winters are great for snowmobiling, but not always great for shipping snowmobiles. (Photo by Dave Gonzalez, MnDOT)
As noted in the report, Minnesota’s extreme winter weather poses unique challenges to its economic competitiveness. Ironically, nowhere is this more evident than in the state’s snowmobile-producing northwest corner.
Polaris and Arctic Cat (together with smaller, more specialized firms like Mattracks) employ thousands of Minnesotans, producing a wide variety of recreational vehicles and accessories that are sold and distributed all over the world. While the companies’ snowmobiles might fare well in a blizzard, the trucks that deliver them don’t. A bad snowstorm can cause delays in both supply and product shipments; it can also prevent employees from getting to work, or even shut down a plant altogether. On a larger scale, these issues make it difficult for the companies to expand at their ideal rates.
The report notes that MnDOT’s 511 system is an important source for many companies to identify and respond to potential shipping delays. It recommends continuous improvements to the system.
The Mayo Clinic (Rochester Area)
Air carriers like FedEx have limited capacity for refrigerated shipments, which creates challenges for shipping medical lab samples. (Photo by Dave Gonzalez, MnDOT)
The Mayo Clinic has become synonymous with the Rochester metropolitan area, and for good reason: it employs 37,000 residents and brings in 500,000 unique patients each year from all 50 U.S. states and 150 countries. As you might imagine, generating that much activity in a community of only 110,000 people creates some unique and significant transportation challenges.
Unlike most competitor institutions (Johns Hopkins in Baltimore, for example), the Mayo clinic is located in a relatively small metropolitan area. The local airport has an older navigation system and offers less direct commercial air service. As a result, it depends on high-quality transit and freight service to help accommodate the constant flow of visitors and supplies. The shipping of highly perishable lab samples is also a challenge, as air carriers have limited capacity for refrigeration. Finally, adverse weather conditions can affect emergency services dispatchers’ ability to send fast modes of transportation such as helicopters.
Hospitality and Tourism (Brainerd Lakes Area)
Lakeside resorts a great way to enjoy Minnesota’s scenic beauty — but getting there can be a challenge. (Photo by Dave Gonzalez, MnDOT)
The oil boom in North Dakota has generated a lot of wealth in a short amount of time, and resorts like the Grand View Lodge in Nisswa would love to capture some of it by enticing new vacationers from the west. The trouble is, the area is inconvenient to reach from that direction.
A four-lane highway makes it easy for visitors from St. Cloud or the Twin Cities to visit resorts in the Brainerd area, but travelers coming from the Dakotas face a more circuitous route. Air travel options help to an extent, as visitors from even farther distances can fly into Fargo and then drive in from there. St. Cloud also has daily air service from Chicago, which helps maintain a constant flow of visitors.
One of St. Paul’s most iconic landmarks is helping the Minnesota Department of Transportation find the most cost-effective methods of maintaining concrete bridge decks.
For the last three years, the Smith Avenue High Bridge, which connects downtown St. Paul with the city’s west side, has served as a test bed for a variety of products used to seal cracks on bridge decks. Through MnDOT-funded research, various sealant products have been applied on different areas of the bridge deck, with their performance tracked over time.
“This project will help MnDOT make cost-effective maintenance decisions to preserve its current bridge infrastructure,” said Sarah Sondag, a senior engineer with MnDOT Bridge Operations Support.
The bridge was chosen in part because of its large deck area, which allowed for the application of 12 sealant products and three control sections.
Sealing deck cracks is a routine preventive maintenance task for bridge crews. Left untreated, cracks can allow moisture and chlorides to penetrate the bridge deck, which can lead to the corrosion of reinforcing steel, deck deterioration and the need for early deck replacement.
A researcher tests the permeability of a crack on the deck of the Smith Avenue High Bridge in St. Paul.
MnDOT maintains a list of approved bridge deck crack sealing products, but until now had little data on how well each one performs in the field. The recently published report also examined several products that are not currently on the Approved Products List.
Among the study’s findings: some of the products on MnDOT’s Approved Products List did not perform as well as other products that are not currently on the list. MnDOT is using the results of the study to update its qualification process for products to get on the approved list. Insights gained from studying application techniques will also be used to update MnDOT’s bridge maintenance manual.
*Note: This blog post was adapted from an article and technical summary that will be featured in the upcoming issue of the Accelerator newsletter.
Crossroads 