Lane-departure crashes on curves make up a significant portion of fatal crashes on rural Minnesota roads. To improve safety, solutions are needed to help drivers identify upcoming curves and inform them of a safe speed for navigating the curve.
“Traditionally there are two ways to do this: with either static signage or with dynamic warning signs,” says Brian Davis, a research fellow in the U of M’s Department of Mechanical Engineering. “However, while signing curves can help, static signage is often disregarded by drivers, and it is not required for roads with low average daily traffic. Dynamic speed signs are very costly, which can be difficult to justify, especially for rural roads with low traffic volumes.”
In a recent project led by Davis on behalf of MnDOT and the Minnesota Local Road Research Board, researchers developed a method of achieving dynamic curve warnings while avoiding costly infrastructure-based solutions. To do so, they used in-vehicle technology to display dynamic curve-speed warnings to the driver based on the driver’s real-time behavior and position relative to the curve. The system uses a smartphone app located in the vehicle to provide the driver with visual and auditory warnings when approaching a potentially hazardous curve at an unsafe speed.
“Highway curves [make up] 19 percent of the total mileage of the paved St. Louis County highway system, yet these curves account for 47 percent of all severe road departure crashes,” says Victor Lund, traffic engineer with St. Louis County. “In-vehicle warnings will be a critical strategy to reduce these crashes.”
To begin their study, researchers designed and tested prototype visual and auditory warning designs to ensure they were non-distracting and effective. This portion of the study included decisions about the best way to visually display the warnings and how and when audio messages should be used. “To create the optimal user experience, we looked at everything from how to order the audio information and when the message should play to the best length for the warning message,” says Nichole Morris, director of the U’s HumanFIRST Lab and co-investigator of the study.
Next, a controlled field test was conducted to determine whether the system helped reduce curve speeds, pinpoint the best timing for the warnings in relation to the curves, and gather user feedback about the system’s usefulness and trustworthiness. The study was conducted with 24 drivers using the test track at the Minnesota Highway Safety and Research Center in St. Cloud, Minnesota. The selected course allowed drivers to get up to highway speeds and then travel through curves of different radii, enabling researchers to learn how sensitive drivers are to the position of the warnings.
Based on the study results, the system shows both feasibility and promise. “Our in-vehicle dynamic curve warning system was well-liked and trusted by the participants,” Davis says. “We saw an 8 to 10 percent decrease in curve speed when participants were using the system.”
The project was funded by MnDOT and the Minnesota Local Road Research Board.
Social media can be effective as a strategic and select part of public engagement plans, according to findings of a University of Minnesota study. Co-principal investigators were Professor Ingrid Schneider of the Department of Forest Resources and Associate Professor Kathryn Quick of the Humphrey School of Public Affairs. “Public engagement for transportation planning and programs is not only required, it’s a crucial component in policy and project success,” Schneider says. “Since 2000, advances in technology and communications provide opportunities to engage with more people in new ways.”
The multipronged, multiyear project investigated current knowledge about public engagement through social media nationwide and in Minnesota. It also developed guidance about how social media may be used to reach and engage diverse populations in the state about transportation planning and projects.
For the analysis, the team used multiple methods: a literature review, telephone interviews, and four case studies. “The literature review indicated social media needs to be part of a multipronged engagement plan,” Schneider says. “While 90 percent of U.S. adults are online and 69 percent use social media, a social-media-only plan may not reach people over the age of 65 or with a high school education only. Platform use also varies considerably: African Americans and Latinos, for example, use video-sharing more than other groups.”
Phone interviews of more than 800 Minnesotans found that 72 percent use social media, and 11 to 21 percent participated in some way in planning transportation programs, policies, and projects in the previous year. In addition, 36 percent expressed interest in using social media to get information, provide feedback, or make suggestions related to transportation programs, policy, and planning.
The case studies compared pairs of transportation projects in Minnesota: two with significant social media use (Richfield, Red Wing), and two with low use (Saint Paul, Detroit Lakes). Findings revealed that the two projects with higher levels of social media had more connections with stakeholders. The quality and effectiveness of those connections, however, varied. “Government social media primarily informed audiences, while community-created pages fostered deeper engagement and dialogue,” Quick says. “In addition, the quality of social media, and their combination with other outreach technologies, influenced stakeholders’ perceptions of the engagement efforts.”
The project was funded by MnDOT and the Minnesota LRRB. “MnDOT and LRRB are committed to listening to and learning from the public,” says Renee Raduenz, MnDOT market research manager. “Social media provides a unique, efficient, and potentially inclusive tool in those efforts. This research brings us one step closer to understanding how we can maximize the power of social media to its fullest.”
Taken as a whole, the findings suggest at least four main opportunities to strengthen meaningful social media engagement:
Integrate social media into multipronged, dynamic engagement approaches. Pay attention and contribute to community-created social media pages, and provide a regular diet of new information and updates.
Consider the demographic qualities of the key stakeholders to determine how social media can be most useful.
Employ best practices for social media management, such as using hashtags to organize data, posting dynamic content (project videos, live streams), and clearly stating social media guidelines.
Expand and/or develop research and evaluation plans to understand and assess future social media engagement efforts.
CTS has been celebrating its 30th anniversary this year with a look back at significant milestones. One of our goals for the anniversary was to show how research progresses over time to lead to new knowledge.
In February we shared videos that trace the path of progress in two of our key research areas: traffic operations and pavement design. Today, at our 28th Annual Transportation Research Conference, we debuted a video about another important research topic: accessibility metrics.
In the new video, Andrew Owen, the director of the U’s Accessibility Observatory, explains how accessibility looks at the end-to-end purpose of transportation: fulfilling people’s need to reach destinations. “The Observatory is pushing the envelope and staying ahead of research into what new types of metrics are possible,” he says.
The Observatory builds on tools and expertise developed in two previous University research studies: the Transportation and Regional Growth Study (1998–2003) and the Access to Destinations study (2004–2012).
Join us at the 28th Annual CTS Research Conference to hear about new learning, emerging ideas, and the latest innovations in transportation. This year’s event is scheduled for November 2 at The Commons Hotel in Minneapolis.
Attendees will learn about research findings, implementation efforts, and engagement activities related to a variety of transportation topics. This year’s keynote presentations feature:
Joung Lee, policy director at AASHTO, on how we pay for transportation infrastructure
Joshua Schank, chief innovation officer at LA Metro, on policy innovation at his agency
“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:
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.
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.
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.
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.
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.
When drivers approach a roadway work zone at high speeds, they put the lives of work-zone flaggers at risk. To keep flaggers safe on the job, U of M researchers are looking for better ways to capture drivers’ attention—and compel them to slow down—as they approach flagger-controlled work zones.
The project began with a simulator study in which participants completed three drives, each featuring a work zone with different warning treatments. One condition was a traditional four-sign configuration currently used to warn drivers approaching work zones. The other two conditions featured a variety of new elements, including signage with new messaging such as a “one-lane road ahead” sign with flashing LED lights, a dynamic speed warning sign equipped with a loud warning horn that sounded if drivers exceeded the speed limit, and portable rumble strips.
“Overall, we found that the new set of elements is more effective than the elements currently used to reduce driving speeds on the approach to a flagger-controlled work zone,” Harder says.
Although adding LED lights to the one-lane road sign had no significant effect on drivers’ speeds, findings indicated that the dynamic speed sign coupled with the horn was more effective than the dynamic sign alone.
To test these new elements under real-world conditions, the researchers conducted field tests evaluating two configurations in Minnesota work zones. The first configuration followed the minimum standards outlined in the Minnesota Manual on Uniform Traffic Control Devices. The second deployed signs employing new messaging and attention-getting devices, including a dynamic speed warning sign, horn, and rumble strips.
Findings showed that the combination of the dynamic speed warning sign and the horn successfully reduced the overall speed of vehicles approaching the work zone. The portable rumble strips did not cause any significant speed reduction, but this may have been related to their location downstream from the dynamic speed sign and horn.
“Our findings reveal that the new set of elements designed to capture driver attention—including new messaging, a dynamic speed trailer, and horn—had a significant influence on reducing driver speed,” Harder says. “The experimental layout practically eliminated high-speed outliers and successfully reduced the approach speed to the flag operator.”
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.
A new app that sends warning messages to drivers as they approach work zones was featured on KARE 11 News on Thursday. The app was developed by U of M researchers in a project sponsored by MnDOT.
The story aired as part of KARE 11’s #eyesUP campaign to end distracted driving.
The app works by pairing with Bluetooth low-energy tags placed in work zones, triggering audio warnings in smartphones that are within their range. This allows drivers to get a warning message without having to look down at their phones—or at warning devices such as changeable message signs outside their vehicles. And if a driver is being distracted by their phone, the app will interrupt whatever they are doing to provide a warning that a work zone is up ahead.
U of M researchers Chen-Fu Liao and Nichole Morris, who worked on the project, are interviewed in the story, along with Ken Johnson, work-zone, pavement marking, and traffic devices engineer at MnDOT.