Tag Archives: transportation research

MnDOT Chooses EasyMile for Autonomous Shuttle Bus Project

ST. PAUL, Minn. – The Minnesota Department of Transportation chose EasyMile, a France-based company specializing in driverless technology, to lead its autonomous shuttle bus pilot project. MnDOT announced in June it will begin testing the use of an autonomous shuttle bus in a cold weather climate.

“We’re excited to partner with EasyMile to help MnDOT test autonomous technology,” said Jay Hietpas, MnDOT state traffic engineer and project manager. “Their expertise will help us learn how these vehicles operate in a winter weather environment so we can advance this technology and position MnDOT and Minnesota as a leader.”

EasyMile, which has a location in Colorado, has conducted driverless technology cold weather tests in Finland and Norway. Minnesota will be their first cold weather test site in the U.S. EasyMile will use its EZ10 electric shuttle bus that has already transported 160,000 people more than 60,000 miles in 14 countries. The shuttle was tested in various environments and traffic conditions. During these tests, the shuttle operated crash-free.

The shuttle operates autonomously at low speeds on pre-mapped routes. It can transport between six and 12 people.

Initially, it will be tested at MnROAD, which is MnDOT’s pavement test facility. Testing will include how the shuttle operates in snow and ice conditions, at low temperatures and on roads where salt is used.

Testing is scheduled to start in November and go through February 2018. The shuttle will also be showcased during the week of the 2018 Super Bowl.

Hietpas said 3M will also be a partner in the project so the company can research various connected vehicle concepts including sensor enhancement and advanced roadway safety materials. When optimized, these materials would aid in safe human and machine road navigation.


Read more about the autonomous shuttle bus pilot project:


Related MnDOT research:

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. 

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.

img_1576
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

10 Ways Transportation Research Keeps Minnesotans Moving in the Winter

As the first big snow and ice storms sweep through parts of Minnesota today, we’d like to remind you of some of our great winter weather research studies. Here’s a list of some of this winter-related research from MnDOT and the Local Road Research Board:

Living snow fences

Living snow fences are trees, shrubs, native grasses, wildflowers, or rows of corn crops located along roads or around communities and farmsteads. These living barriers trap snow as it blows across fields, piling it up before it reaches a road, waterway, farmstead or community. Through multiple research efforts, MnDOT continues to advance its practices for living snow fences. Willow plants, which are which are inexpensive and fast-growing, are a new form of snow fence. MnDOT has also developed a tool that allows the agency to better offer a competitive payment to farmers.

Related studies:

Permeable pavement

According to recent studies, researchers believe Minnesota could eliminate salt usage on low-volume local roads by switching to permeable pavements. Permeable pavements — pavements that allow water to seep through them — have been studied in some Minnesota cities, and a research project is currently underway to further investigate how much salt reduction can be expected.

Related studies:

Traffic recovery during winter storms

MnDOT’s Metro District developed a way to automatically determine when to stop plowing a highway after a snow storm. The method involves measuring traffic flow to determine when road conditions have recovered. Current practice calls for maintenance workers to visually inspect traffic lanes. The automated technique could potentially be more accurate and save time and costs.

Related study:

Salt and other deicing chemicals

Minnesota winters are no joke, and Minnesotans still need to get wherever they’re going despite harsh snow and ice conditions. That’s why MnDOT is constantly researching new and improved versions of salt and other deicing chemicals to keep roads safe at the least amount of damage to lakes, rivers and groundwater.

Related studies:

Snowplow blades

A couple years ago, MnDOT snowplow operators in southwestern Minnesota invented an experimental plow that uses the wind to cast snow from the road without impeding traffic or the operator’s view. This winter, MnDOT intends to test multiple types of snowplow blades as part of a larger research project comparing types of deicers.

Related study:

Snowplow technology

While a lot of research has been done on the plow itself, MnDOT hasn’t forgotten to invest in research to improve in-cabin snowplow technology as well. Some of the great technology recently developed to assist snowplow drivers, includes a driver assist application that a MnDOT plow driver used last winter to navigate a storm and rescue stranded motorists. The agency is also studying equipment factors that can cause fatigue in snowplow operators.

Related studies:

Salt-resistant grasses

When the snow melts every spring, the damage salt does to roadside grass is obvious. That’s why researchers have spent years looking into developing and implementing salt-tolerant grasses on roadside settings. The result of this effort has been the introduction and use of salt-tolerant sod and seed mixtures that are made up primarily of fine fescue species. MnDOT is also studying how chlorides are transported within watersheds in order to better focus efforts to reduce deicer usage in  areas where it will have the biggest environmental impact.

Related studies:

Cold-weather cracking prediction test

MnDOT has developed a test that can tell whether a contractor’s proposed asphalt mix will cause the road to crack in the winter. Building roads using better asphalt mixes leads to less cracking and fewer potholes. The test is expected to save the state about $2 million per year.

Related studies:

Pedestrian snow removal

It’s not all about cars and trucks. Minnesotans still ride bikes and walk in the winter. That why MnDOT assembled a comprehensive review of existing practices and policies from other states, as well as a summary of valuable publications that could be referenced while developing a new policy.

Related study:

Maintenance Decision Making

MnDOT research led to the development of a Maintenance Decision Support System and related components provide real-time, route-specific information to snow plow drivers, as well as recommended salt application levels. These recommendations have reduced chemical usage while still achieving performance targets for snow and ice clearance.

Related studies:

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

The Future is Now: MnDOT Goes High-Tech

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.

13-JamesBenhamTechnology300
James Benham, JB Knowledge, speaks at the Transportation Conference. (Photo by Rich Kemp)

Last month at Minnesota’s Transportation Conference, a keynote session by JB Knowledge CEO James Benham titled “Future Forecast: How Drones, Sensors, and Integrated Apps are Rewriting the Rules” inspired many people in the room.

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.

In January, MnDOT Research Services published these papers in a report titled “The Transportation Futures Project: Planning for Technology Change.”

GoogleCar
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)

Drone
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 photo
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.

A look at five great environmental research projects

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.

1: Reducing Road Construction Pollution by Skimming Stormwater Ponds 

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.

2: Roadside Drainage Ditches Reduce Pollution More Than Previously Thought  

Photo of roadside ditch
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.

3: Could Permeable Pavements Eliminate Road Salt Use on Local Roads? 

Robbinsdale
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.

4: Highway 53 Shows Potential of Using Road Construction Excavation Areas For Wetland Mitigation

IMG_2764
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.

5: Recycling Method Could Give Third Lives to Old Concrete Roads 

2016-14 Image
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.

Driver-assist system helps keep plows on the road

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)
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 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 saves time, money with new contracting method

Thanks to a flexible new contracting method, the cost and time of delivering small highway projects in Minnesota should go down.

The Minnesota Department of Transportation is now able to put road construction contractors on standby for certain types of projects, rather than bid each project individually, due to the adoption of Indefinite Delivery/Indefinite Quantity (IDIQ) contracts.

“IDIQ contracts give MnDOT more flexibility and the ability to get to the field quicker for work that we need repeated routinely, such as culvert repairs, overlays and seal coats,” said Kevin Kosobud, project development engineer with MnDOT’s Office of Construction and Innovative Contracting.

IDIQs also provide flexibility when needs are uncertain.  Contracts are often used for multiple small projects that are similar in scope, but difficult to quantify in cost and timing.

For instance, the state of Florida awards IDIQs for hurricane debris removal, activating and paying contractors only when a hurricane necessitates the service.

Although IDIQs showed great promise, MnDOT had to develop a framework to implement them.

The federal government has used IDIQ contracts since the 1980s, but only a small number of state DOTS have used them to procure construction services. No standard procedures existed for their use by state DOTs, and federal procedures are not always applicable at the state level.

MnDOT hired Iowa State University researchers to examine IDIQ usage across the country and develop implementation procedures for Minnesota. (Read a summary of their research here.)

Researchers examined contracting practices at 14 different transportation agencies to  recommend guidelines for Minnesota to follow, which allowed MnDOT to begin awarding IDIQ contracts in April 2013.

Case study analyses show clear benefits where IDIQ has been used: acceleration of the project delivery period, reduced construction costs and flexible delivery scheduling.

“IDIQs can help DOTs get better prices for routine services via an economy of scale, for instance, by awarding a contract for a larger number of culvert repairs rather than awarding a single contract for each repair,” explained Doug Gransberg, professor of construction engineering at the Iowa State University Institute of Transportation.

Agencies can award IDIQ contracts individually or collectively.

With a single-award contract, a single contractor is awarded task orders based on the pricing furnished in the initial bid package; multiple-award contracts determine a pool of qualified contractors who may subsequently bid on task orders.

*Editor’s note: This article was adapted from the September-October 2014 issue of our Accelerator newsletter. Read it online or sign up for your free subscription.

Related Resources
  • Leveraging the Advantages of Indefinite Delivery/Indefinite Quantity Contracts – Technical Summary (1 MB, 2 pages); Final Report (expected Fall 2014)

Why is all the colored concrete deteriorating so fast?

There’s nothing like colored concrete to make a crosswalk, sidewalk or breezeway look snazzy.

But the extra touch that many cities are putting into their downtown streetscapes may not be so pretty in just a few short years.

Early cracking has prompted the city of Vadnais Heights to tear up its colored concrete, and the city of Centerville — which installed colored concrete only six years ago — plans to follow suit, said MnDOT’s Senior Road Research Engineer Tom Burnham.

Both cities participated in a recent study, sponsored by the Local Road Research Board and conducted by MnDOT, to determine what is causing the early deterioration.

Across Minnesota, many of the estimated 45 colored concrete projects have experienced early deterioration, particularly microcracking near contraction joints. While this type of distress also occurs with regular concrete, it appears to be accelerated in the colored concrete projects, within five years in some instances.

Although the newly released study identifies likely causes for the failing colored concrete, further research is needed to evaluate proposed solutions.

Findings

Researchers determined that the colored concrete mixtures have likely been too porous for Minnesota winters, allowing deicing chemicals to leach in and wreak havoc. Although not quite as problematic for sidewalks and medians — which aren’t salted as heavily — it is especially bad for colored crosswalks.

A denser concrete mixture (one formed with less water) is recommended; however, constructing the concrete panels this way will require extra steps.

“There are chemicals that can be added to the mixture to artificially lower that water-to-concrete ratio,” Burnham said. “This will allow a  denser mixture to be more easily placed.”

The city of Centerville plans to tear up its colored concrete. This photo shows early joint deterioration.
The city of Centerville plans to tear up its colored concrete. This photo shows early joint deterioration.
Color in vogue

Although there was a spate of colored concrete construction in Ramsey County in the late 1990s, it has only come into fashion in the rest of the state within the last five to six years, according to Burnham.

“You go to almost any community and they’re installing it — on their sidewalk and medians and also crosswalks,” said Burnham, who coordinated the research study.

Because of the added expense, cities may be very disappointed in the results.

The city of Stillwater, which installed a colored concrete panel crosswalk on its main street just two years ago (see top photo), is already experiencing cracking and deterioration in several panels.

Possible remedies

Although reducing the porosity of the colored concrete mixture should help,  it won’t solve everything.

Another issue is the curing. The typical white curing product can’t be applied like it is with standard concrete, so curing the colored panels is more challenging, Burnham explained.

There are possible remedies, however, to assist with the curing, such as wet burlap or curing blankets.

Adding complexity to the issue are the new deicing chemicals on the market, which are also impacting regular road materials.

Several test samples showed evidence of chemical attack of the cement paste and fine aggregates, as well as an alkali-silica reaction, which can cause cracking or spalling and isn’t normally seen in regular concrete.

“Is there anything unique with the coloring that would accelerate the observed chemical reactions? We didn’t feel we had enough samples and knowledge at this point to conclusively say,” Burnham said.

Different construction techniques could go a long way toward increasing the livelihood of colored concrete; however, it could take several years of observation to determine if other methods work.

MnROAD is considering adding colored concrete panels to its facility for testing.

Until more questions are answered, MnDOT researchers are recommending repair techniques and alternative streetscaping ideas to cities, such concrete stains, pavers or colored high friction surface treatments.

In addition to sharing the findings with cities and counties, Burnham wants to educate contractors.

“We hope this research is a wake-up call for the colored concrete industry too because we don’t want the industry to die in Minnesota,” he said. “If it can work, we want cities and counties to be able to use it.”

*Editor’s Note: This story was updated 09/04/2014 to specify that this research project was funded entirely by the Local Road Research Board, and that MnDOT conducted the research.

Related Resources
  • Investigation and Assessment of Colored Concrete Pavement — Final Report (PDF, 20 MB, 368 pages); Technical Summary (forthcoming)