Tag Archives: research

Maintenance Operations

New study to shed light on environmental impacts of deicers

Leave a comment

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

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

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

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

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

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

About Clear Roads

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

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

Maintenance Operations

Robotic message painter could help keep road crews safe

Leave a comment

Using rollers and stencils to draw turn arrows and crosswalk stripes on roads seems a bit archaic to MnDOT District 3 Maintenance Superintendent Randy Reznicek, who asked researchers if they could develop an automated road message painter.

University of Minnesota-Duluth Associate Professor Ryan Rosandich has taken that vision and created an robotic arm that can spray-paint pavement signs, with the goal of saving crews time and keeping them safer.

Designed to be mounted to the front of a maintenance vehicle, the robot is operated remotely by a laptop, programmed with numerous types of messages.

In an earlier prototype, researchers developed a trailer painter that could be pulled behind a truck.

Crews currently use heavy, eight-foot by four-foot stencils and rollers to paint designs, with an estimated 75 percent of such work involving the repainting of existing markings.

“It takes two people to lift the stencils,” explained MnDOT maintenance worker Joe Gilk, whom Reznicek presented with the idea about five years ago. “This would eliminate one position. One person could just run the truck and you could use that other person in another area of our job.”

Rosandich, who heads the Mechanical and Industrial Engineering Department at the University of Minnesota-Duluth, led the initial development of a software system and trailer painter.

MnDOT has funded further research to develop the more technically difficult robotic arm, which it anticipates could be used in other aspects of maintenance work as well.

MnDOT District 3 maintenance worker Joe Gilk, left, and maintenance superintendent Randy Reznicek watch the demonstration of the robotic message painter, an idea that came from their office.
MnDOT District 3 maintenance worker Joe Gilk, left, and District 1 traffic engineer Rob Ege watch a demonstration of the robotic message painter, an idea that came from Gilk’s office.

Rosandich recently demonstrated the mechanical arm to a MnDOT road crew (no paint was used during the demonstration), but additional software and mechanical tweaks remain before researchers take the machine out for final testing on the pavement this spring.

A companion vision system is being developed to identify existing markings to guide the robot in the repainting of existing messages.

The robot’s three-segmented aluminum shell arm is capable of painting up to a 12-foot wide lane and has enough battery power for a whole day’s worth of work, Rosandich said.

Once the prototype is complete, researchers hope to find a manufacturer to develop and produce a machine that could be used by maintenance crews across the state. MnDOT has already had great success in deploying automated pavement patching systems in some districts.

Not only would a robotic message painter free up maintenance crews and speed up sign-painting, but Rosandich sees worker safety as its “biggest selling point.”

The start-up cost for manufacturing such a device is estimated to be $150,000.

Maintenance Operations

New videos show how frost heave ravages roads

Leave a comment

Regardless of whether you’re familiar with the term “frost heave,” if you live in Minnesota and drive on the roads, you’re already familiar with its destructive capacity. Many of the dips, bumps, potholes and cracks that appear on our roads every spring are a direct result of frost heave, which occurs when water accumulates in the soil beneath the pavement and begins freezing and then thawing along with the changing seasons. The resulting expansion and contraction weakens the road base and leaves it susceptible to damage from traffic loading.

These new videos produced by the Local Road Research Board explain how frost heave works, and describe some of the strategies public works departments use to combat it. The top video is is the shortened, executive-summary version, while the bottom video is the full, 13-minute version meant for transportation professionals.

Bridges and Structures

MnDOT tests new technologies to monitor bridge scour

1 Comment

A research implementation project could provide MnDOT with a new set of tools to help combat a major source of bridge failure.

The MnDOT Bridge Office is testing several new methods of monitoring bridge scour — erosion that occurs around bridge piers and abutments during high water-flow events like floods. Acting Waterway Engineer Nicole Danielson-Bartelt said the project’s goal is to be able to monitor scour-critical bridges remotely rather than sending maintenance personnel out on the water during difficult or hazardous conditions.

“There are a number of bridges that are pretty difficult to monitor, especially during high water events,” she said. “Typically, you need to get out on a boat and do either sonar readings or drop weights. It’s dangerous work to be out on the water during those types of events unless you have the right training.”

The project will evaluate several different monitoring technologies, including continuous monitoring equipment like tilt meters and active sonar. The sonar systems, which allows continuous stream bed and water surface elevation data to be transmitted to a website for graphical display, could provide benefits that go beyond monitoring individual bridges.

“The ability to collect continuous, long-term data could help engineers understand short term scour-fill and long term aggradation-degradation cycles,” said Solomon Woldeamlak, a Bridge Office hydraulic engineer. He added that the data can be used to calibrate existing methods of estimating scour at bridges.

Other devices being tested include “float-out” devices, which are buried in the sand around the abutment and send out a signal only if washed to the surface by a scour. Danielson-Bartelt said these non-continuous monitoring devices might be appropriate for bridges where installing permanent sonar is not advisable due to the presence of debris that could damage the equipment.

Monitoring equipment has been installed at two locations: the Highway 43 Winona bridge over the Mississippi River and the Highway 14 Mankato bridge over the Minnesota River. A final report on the project is expected in late 2014/early 2015. You can learn more about some of the products that are being tested on the website of ETI Instrument Systems, Inc., which provided the equipment.

Traffic and Safety

‘Intelligent’ traffic drum could help prevent work-zone tragedies

2 Comments
2012-26 Image
A prototype of the Intelligent Drum Line system.

Work-zone safety is a serious, ongoing challenge for transportation agencies. According to MnDOT, the current three-year average for Minnesota work zones is 1,819 crashes and seven fatalities per year. And that’s not counting near-misses: just talk to anyone who has worked as a flagger, and they will likely have a story about diving into a ditch to avoid being hit by a distracted driver. Consequently, MnDOT is constantly exploring ways to make work zones safer — which brings me to the photo above.

What you’re looking at is no ordinary traffic cone. It’s a prototype of a new warning device called the Intelligent Drum Line system — basically a modified orange traffic drum packed with electronics that can detect speeding drivers and blast them with audiovisual cues to let them know they’re entering the work zone too fast.

Our new technical summary explains the details of the new system, which was developed at the University of Minnesota, with funding and in-kind assistance from MnDOT:

The prototype design uses two modified traffic drums placed 1 to 3 feet from the shoulder of the road and 300 to 400 feet apart. Sensors in the first drum detect vehicles, measure their speed and distance, and communicate this information to the second drum…

When the IDL system detects an oncoming vehicle traveling faster than a threshold speed, the system activates visual warning systems in both drums and initiates a countdown. When the speeding vehicle is approximately 1 second away from the first drum, the system activates an air horn to warn the driver.

As the vehicle passes the first drum, the audible alarm terminates and the system transmits a command to the second drum to start another countdown. When the vehicle is approximately 1 second away from the second drum, the system activates another audible alarm.

Testing of the IDL system at MnROAD has been successful; however, researchers still need to study how drivers react to the system in real-world conditions. Before they can do that, the design will have to be refined so that it can pass Federal Highway Administration crashworthiness tests. On a related note, MnDOT is currently funding a separate University of Minnesota study into which technologies are most effective at capturing drivers’ attention in work zones. The study will include visual and auditory cues similar to the ones used in the IDL prototype.

Learn more:

Research

Previewing MnDOT’s next round of research projects

1 Comment

MnDOT Research Services recently released its 2013 request for proposals. If you have any kind of direct interest in transportation research in Minnesota, chances are you might have known that already. But those with more of a general curiosity might be interested to see the list of research need statements from the RFP, as they provide a nice preview of the next round of potential MnDOT research projects.

As you can see, some are of a highly technical nature. (It’s safe to say that a study on “PCC Pavement Thickness Variation Versus Observed Pavement Distress” would be of interest mainly to engineers.) Others, however, like “The Economic Impact of Bicycling in Minnesota,” might have a broader appeal. In any case, it’s a fascinating glimpse at the myriad of issues that MnDOT is attempting to address through research and innovation.

Here’s the list of research need statements from the 2013 RFP, broken down by category:

Environment

Maintenance

Materials and Construction

Multimodal

Policy and Planning

Traffic and Safety

Policy and Planning, Public Transit

What happens when you incentivize transit use during construction projects

Leave a comment

In 2010, MnDOT began a three-year long, $67 million repair and upgrade project on I-35 in Duluth. Dubbed the “Mega Project,” it created a serious disruption for Duluth-area commuters. To help mitigate the impact, the Duluth Transit Authority stepped up its bus services, offering free rides in newly established bus-only express lanes as well as access to new park-and-ride lots and various other enticements. Perhaps not surprisingly, many area residents took advantage of their new transit options to avoid construction-related travel delays. But what’s really interesting is what happened after the construction ended.

As described in a recently published MnDOT/University of Minnesota study, commuters who started taking the bus to avoid traffic caused by the construction ended up continuing to ride the bus even after the construction ended. Researchers surveyed riders during and after the 2010 and 2011 construction seasons and found that, even after bus fares went back to normal levels, only 15 percent of the new bus users switched back to driving. Researchers concluded that once riders developed a habit of using transit, the habit tended to stick.

The report author sums up the phenomenon quite nicely in her executive summary:

Human beings are creatures of habit. Most of us travel the same route every day to the same destination. Sometimes, however, something comes along to push us to examine our habits and possibly change them. A major highway construction project can be such an event. (…) This provides a very good opportunity to examine our travel patterns and possibly change our habitual modes.

Of course, this change didn’t just happen on its own. As the technical summary notes, the DTA marketed its services aggressively during this period. (The above photo is just one example.) The study also noted that the elimination of expanded bus services in the winter had a negative impact on ridership.

Read more:

Materials and Construction

Geotextile research at MnROAD

1 Comment

Geotextiles are synthetic polymer materials used to improve the performance of roadways. As discussed in this 2011 technical summary, geotextiles facilitate filtration and water drainage, improve the integrity and functioning of base materials, and provide a stable construction platform over soft or wet soils. These improvements can benefit both the cost-efficiency and longevity of pavements.

Geosynthetic materials have been used throughout Minnesota, and can be found in both reconstructed and new roadway projects. The use of geotextiles as a separator layer under concrete overlays, however, has had limited documentation in Minnesota and other cold weather climates. MnROAD‘s recent dedication of several test cells to this purpose will determine the performance of this application of geotextiles, with the goal of improving its applications on other Minnesota roadways.

The new test sections, designated as Cells 140 and 240, consist of a very thin, 3-inch concrete overlay over an existing 7-inch concrete pavement constructed 20 years ago. Some unique features of the design include the use of a fiber-reinforced concrete mix, two different thicknesses of the nonwoven geotextile, and the use of a special type of glue, rather than nails, to fasten it to the existing concrete before paving.

The fabric and fiber used in the concrete mix were supplied through a public-private partnership with Propex Geotextile Systems. The results of this study, along with other unbonded overlays constructed at MnROAD and around the country, will be incorporated into a new national pooled fund project — TPF 5-(269) — led by MnDOT. This project will develop an improved mechanistic design procedure for unbonded overlays.

A second application being demonstrated at MnROAD is the use of a geosynthetic drainage system under several dowel bar baskets in new concrete pavement test section. Minnesota has historically used a dense-graded base layer under concrete pavements to provide a stable foundation and construction platform. However, this material drains very slowly, and traps moisture within the joints, leading eventually to significant distress (See Effect of Drainage on the Performance of Concrete Pavement Joints in Minnesota.) This application will compare the use of the geotextile drainage material placed under both sealed and unsealed joints, as well as a control joint without the drainage material.

Traffic and Safety

Best practices for trail crossings – webinar and draft report

Leave a comment

Last week, MnDOT Research Services hosted a workshop on a forthcoming report, “Decision Tree for Identifying Alternative Trail Crossing Treatments.” It was broadcast as a webinar, the recording of which is now available online via Adobe Connect:

http://mndot.adobeconnect.com/p8hlfripuwe/

The final report is coming soon, but in the meantime you can see the draft version on our website (link), along with case studies and other related documents.

Research

Bridging the gap between research and implementation

1 Comment

The end goal of transportation research, broadly speaking, is to see the results implemented — that is, to transfer the knowledge generated through research to those who can put it to good use. Research Services and the Center for Transportation Studies use a variety of tools to help disseminate research results: our respective websites, email lists, social media, newsletters and this blog, to name a few. But what do we know about how our audiences actually interact with these various channels of communication?

At the Transportation Research Board Annual Meeting earlier this year, researchers from Nebraska presented the findings of a very interesting survey on how engineers and other transportation practitioners prefer to learn about research results. Their presentation, entitled “What Engineers Want: Identifying Transportation Professionals as an Audience for Research,” is available via Slideshare. (Unfortunately, WordPress won’t let me embed it.)

Some key takeaways from the survey:

  • Practitioners overwhelmingly prefer one- or two-page technical briefs to other types of research communication products. (Other popular formats include presentations, video highlights and webinars.)
  • By a wide margin, practitioners use search engines like Google or Bing to seek research results (compared to other options like contacting a colleague or university faculty).
  • Practitioners are mostly interested in information on how to implement findings, as well as cost-benefit analyses of implementation.

The survey results present what I think is a fairly realistic and nuanced picture of the audience for transportation research; they’re also consistent with our (Research Services) own internal research on the issue. The bottom line is that research results need to be condensed into usable bits of information and made easily accessible in a variety of formats. People want information they can use, without having to dig for it. More importantly, they want it in whatever their preferred format is, whether it be print, email, Web, RSS, social media or in-person presentations.

Interestingly, Research Services already produces the kind of two-page technical briefs described in the survey. We call them “technical summaries,” and they are among our most popular products. We generally produce a technical summary for each research project we manage, and post them on our website alongside the full research report. Reading a two-page summary, written in layman’s terms, is certainly easier than poring over research reports that oftentimes number in the hundreds of pages, so it’s not surprising that even those with a strong engineering background prefer the format.

As a side note, last Friday we published a batch of 10 new technical summaries — along with two new transportation research syntheses, which are a type of literature review. Topics range from pedestrian and bicycle safety in roundabout crossings to the effect of intelligent lane control systems on driver behavior. You can check the full list on the Research Services main page.

Now it’s your turn: What forms of communication do you think are most effective at reaching transportation practitioners? Which ones do you prefer? Let us know in the comments.