University of Minnesota Driven to Discover

development.jpgA new research study is recommending ways to make it easier for developers and employers to select sites that encourage living-wage jobs and mixed-income housing near transit.

A key finding of the study, which was based on interviews with developers and business leaders, revealed a pent-up demand for transit access in the Twin Cities metropolitan region.

A team led by University of Minnesota researchers Yingling Fan and Andrew Guthrie found that providing a great work location is critical for employers in recruiting highly skilled young professionals who are likely to desire--or demand--urban living and access to transit.

They also found that multifamily residential developers, redevelopment specialists, and large corporate office tenants have a strong interest in transit-accessible sites, but regulatory barriers, cost issues, and uncertainty surrounding future development of transit often discourage both developers and businesses from selecting such sites.

More details about the study and key recommendations

Warning system aims to alert drivers to potential crashes

| No Comments

Between 2009 and 2011, 55 percent of Minnesota's fatal intersection crashes occurred at rural two-way-stop intersections. Right-angle crashes, often a result of drivers' inability to recognize a safe gap in traffic, account for most of these. When a curve or hill creates a limited sight distance at the intersection, safety issues are compounded.


In the latest phase of the project, researchers removed the "When Flashing" label from the warning sign and added LED flashing lights to the existing stop sign.

In research sponsored by the Minnesota Local Road Research Board, a team from the University of Minnesota Duluth (UMD) Department of Electrical and Computer Engineering, working with St. Louis County, developed a low-cost dynamic warning system to improve the safety of these intersections. The ALERT System uses LED flashing signs that are activated when a vehicle is detected approaching the intersection.

In the first phase of the project, the system was installed at a sight-restricted, two-way-stop intersection in Duluth. Drivers on the major road saw signs with the message "Cross Traffic When Flashing," while drivers on the minor road saw "Vehicle Approaching When Flashing." The aim was to help drivers on the minor road determine a sufficient gap to safely complete their turn and to warn drivers on the major road that a vehicle was stopped or entering the intersection from the minor road.

Study results showed that when the alert signs were flashing, vehicle speeds on the major road decreased, drivers on the minor road waited longer before crossing, and vehicle "roll-throughs" of the stop sign were eliminated.


However, a significant unintended consequence was also observed, says research assistant Husam Ismail. "We discovered that the drivers depend completely on the warning sign, so they're ignoring the stop sign," Ismail says. Consequently, when the alert sign was not flashing, drivers on the minor road may have assumed there was no cross traffic, and the number of roll-throughs increased.

This raises the risk of a crash if the device stops working and could indicate an overdependence on the warning system, Ismail says. Local residents voiced similar concerns, worried that some drivers would no longer obey stop signs or look for oncoming vehicles when the warning signs weren't flashing.

The current phase of the project, ALERT-2, aims to reduce the percentage of roll-throughs on the minor road as well as improve the design for easier maintenance. Besides Ismail, the team for this phase includes UMD professor Taek Kwon and traffic engineer Victor Lund with St. Louis County Public Works.

As part of the new phase, researchers replaced the static stop sign with an LED blinking stop sign and removed the "When Flashing" label under the warning sign. Cameras and detectors captured both before- and after-installation data on roll-throughs at the intersection, which the team expects to analyze by fall 2013.

"We need the vehicle on the minor road to respect the stop sign, whether there's a conflict [present] or not," Ismail says. If the percentage of roll-throughs can be reduced, he adds, the system could significantly improve the safety of rural intersections with severe sight restrictions.

According to Lund, the system shows promise to improve intersection safety by helping drivers make good decisions for turning movements. "The next step is to deploy dozens of these systems so that further research can be completed on developing a crash-reduction factor," Lund says.

Reprinted from CTS Catalyst, July 2013.

Investigating air pollution risks for pedestrians and cyclists

| No Comments

Although active forms of travel such as bicycling and walking provide many health benefits, they may also increase travelers' exposure to air pollution—especially in urban areas, where the air pollutants that drive health concerns are typically at their highest concentrations.


To investigate the exposure of cyclists and pedestrians to these pollutants in the City of Minneapolis, researchers from the U of M's Department of Civil Engineering (CE) are developing a block-by-block analysis of air pollution levels. In a presentation at the 24th Annual CTS Transportation Research Conference on May 23, graduate student Steve Hankey explained how this information could ultimately be used to identify high-risk locations and shape decisions about new nonmotorized infrastructure. The project is funded by the U of M's College of Science and Engineering and the Humphrey School of Public Affairs.

In summer 2012, Hankey collected particulate air pollution measurements in Minneapolis using an instrumented bicycle trailer as he rode around the city on three 20-mile routes. Each route captured different levels of traffic and air pollution, Hankey said, and included a wide variety of road types and surrounding land uses.

Preliminary findings suggest that air pollution levels are 1.5 to 2.3 times higher in on-road locations than on off-street trails and 2 to 3.5 times higher in the morning than in the afternoon. Results also indicate that air pollution concentrations are associated with street classification and traffic intensity.


Arterial streets with the most traffic had the highest air pollution levels, with lower concentrations on local roads and off-street trails. "If you can choose to bike on a local road that's a block or two off an arterial collector, that would make a big difference in your exposure," Hankey said.

The project's next step is to tie the existing mobile measures to land-use variables so the data can be extrapolated to other parts of the city, Hankey said. The resulting model will show air pollution levels for every block in Minneapolis.

The researchers plan to use this model in conjunction with bicycle and pedestrian traffic volume data being collected by a team of researchers from the Humphrey School led by Professor Greg Lindsey. The combined model could be used to identify "hot spots" with both large volumes of pedestrian or bicycle traffic and high levels of air pollution, Hankey said.

This information could be used to develop mitigation strategies in high-risk locations and to make recommendations for the development of future infrastructure in areas with lower pollution concentrations.

"We'll also release the air pollution estimates so people can integrate them into existing tools," Hankey said. "For example, in [the bike route tool] Cyclopath, a user could choose a low air pollution route instead of the fastest route or shortest route."

Reprinted from CTS Catalyst, July 2013.

A new wave of technological change in transportation

| No Comments

From social media to intelligent transportation systems, technology is rapidly changing the transportation landscape to create "new mobility"—a trend that was the focus of Elizabeth Deakin's luncheon presentation at the 24th Annual CTS Transportation Research Conference.


"New mobility isn't just about moving people—it is integrating new technologies and new ways of delivering sustainable transportation services that gives people access to more goods, services, and opportunities," said Deakin, a professor of city and regional planning at the University of California, Berkeley.

A number of transportation trends fall under the definition of new mobility, Deakin said, including car sharing, bike sharing, carpooling, smart transit, smart cars, and smart highways. Importantly, while these new mobility approaches have typically been used in urban areas, many of the ideas—such as car sharing, ride sharing, and bike sharing—can work in rural settings as well.

The reasons for the growing interest in new mobility are diverse. From a government perspective, it can enhance mobility, save money, reduce congestion, decrease environmental impacts, and improve public health. For users, it creates more transportation options, greater flexibility and affordability, and health benefits while promoting environmental and social responsibility.


One of the driving forces behind the shift toward new mobility appears to be Millennials—the generation of 20-somethings that grew up building online communities through social media sites such as Facebook and Twitter. Today, they are using social and mobile technology to build communities in the real world—and transportation is no exception. Dynamic ride sharing is just one example: commuters use their smartphones or tablets to request or offer a ride on the fly; the device's GPS navigation capability is used to arrange the ride's pick-up and drop-off points. "We've also seen an increasing interest in services where users create a network of friends and offer dynamic ride sharing only to that known group," Deakin said.

Another growing carpooling trend is "casual carpooling," in which drivers pick up passengers from established locations to share a ride without an ongoing arrangement. "It's sort of like hitchhiking but more organized," Deakin said. "The benefit is that adding riders qualifies the car for HOV lanes and saves everyone significant time off their commute."

New mobility may also change our transportation system's future. Transit will likely get a boost from new technologies that improve travel times with exclusive lanes, signal preemption, off-board fare payment, and more. On the highway, the use of sensors to monitor traffic and control flows will help the whole system run more smoothly; vehicle-highway communication and vehicle sensors will improve safety.

According to Deakin, the move toward new mobility may be a way to bring together diverse views of transportation's future. "One vision of the future is cities that are transit-oriented, while others envision a new world of vehicles that basically drive themselves. New mobility may be the way we integrate those two visions by matching them to the local context to create a transportation system that goes beyond a one-size-fits-all approach."

Reprinted from CTS Catalyst, July 2013.

Driving better health through transportation

| No Comments

In the world of transportation, the focus is most often on creating mobility and accessibility. But according to Minnesota Department of Health Commissioner Edward Ehlinger, transportation also plays a major role in creating health. Delivering the keynote address at the 24th Annual CTS Transportation Research Conference, Ehlinger told the crowd, "Transportation is around us every day and influences everything we do, which makes it integral to creating the conditions for great health."


As an example of the many ways health and transportation are intertwined, Ehlinger shared a list of community indicators for health and quality of life, including access to recreation, access to healthy foods, access to medical services, and access to public transit—all of which have clear ties to transportation.

Transportation-related environmental factors such as air quality are also related to public health: vehicles create about half of all air pollution, and poor air quality leads to public health problems like asthma and lung cancer.


On the other hand, transportation also has historically been a major contributor to public health improvements, according to Ehlinger. "In the 20th century, Americans added 30 years to their life expectancy; 25 of those added years have been linked to public health accomplishments, including transportation-related improvements such as vehicle safety advances and increased seat belt use."

However, in recent years, gains in longevity have leveled off. "Chronic disease has become the leading cause of death, but instead of focusing on prevention we are investing about 95 percent of our resources into medical care," he said.

To continue improving health in the 21st century while also getting health care costs under control, Ehlinger advocates the concept of health in all policies. "Health in all policies takes a collaborative approach to health by integrating health considerations into policymaking and programming across all sectors, and transportation is a key part of that."


Promisingly, recent transportation trends offer tremendous opportunities for public health improvements. Transportation safety initiatives aimed at eliminating crash-related deaths and serious injuries, such as the Minnesota Toward Zero Deaths program, have led to a marked decline in traffic fatalities during the past decade.

In addition, the number of vehicle miles being driven in the United States is dropping, and young people are leading that trend. "If we drive fewer miles, we will reduce the likelihood of obesity. The question is whether this trend will reverse or continue, and that is largely up to the transportation community," said Ehlinger.

"Transportation is in the midst of transformational change ... from a model that moves cars to a model that moves people through a safe, accessible, and affordable system," said Ehlinger. "This is our opportunity to reshape the transportation system and create the infrastructure we need while also improving our health and quality of life."

Reprinted from CTS Catalyst, July 2013.

New fuel cell prototype could power rural ITS applications

| No Comments

Intelligent transportation systems (ITS) technologies can be used to enhance transportation safety and mobility, but the sensors and communications equipment needed for ITS applications typically require access to electricity. In rural areas, limited access to the power grid can make it challenging to implement ITS devices.

Current solutions for providing power to off-grid locations include battery packs or diesel generators, both of which require constant maintenance to recharge, refuel, or replace. Other alternatives include solar panels and wind turbines, but cost and performance concerns have limited their use.


"One of the issues with these green power alternatives, such as solar panels, is dependability... especially in the long, cold, and dark Minnesota winters," says Victor Lund, a traffic engineer with St. Louis County Public Works. Until this technology matures, there is a need for other options that can provide confidence in generating power, Lund says.

To provide a more effective and dependable power alternative, researchers from the University of Minnesota Duluth (UMD) have developed a portable prototype system that uses hydrogen-based fuel cells to generate electricity. The UMD research team was led by chemical engineering associate professor Steven Sternberg, and the project was sponsored by the ITS Institute.

The hydrogen-based fuel cell provides a clean, compact, high-efficiency energy source for an accompanying battery pack, which could be used to operate various ITS devices. The prototype is completely independent of the power grid, works well in cold weather, and requires maintenance only once each week for recharging. The cost of the system is about $7,500, with an additional operating cost of $2,000 per year for fuel materials.

Potential applications include powering variable message signs, dedicated short-range communication technologies, and warning blinkers on traffic signs. According to Lund, the system's applications extend beyond powering ITS devices. For instance, the fuel cells could be used for rural intersection roadway lighting or as a back-up source for traffic signals in case of a power outage.

Reprinted from CTS Catalyst, June 2013.

Photo source:

Rebuilding stronger, less expensive roads with recycled asphalt

| No Comments

While the eco-friendly mantra "reduce and reuse" has been around for decades, its role in asphalt pavement rehabilitation has been discovered much more recently. In years past, when an asphalt road began to deteriorate, the answer was either to apply a hot-mix asphalt overlay to the road's surface or perform a complete reconstruction of the pavement.

"The problem is that other options should be considered," says University of Minnesota civil engineering professor Joseph Labuz. "Fully reconstructing a road is expensive and time consuming, and though the overlay method is fast and less expensive, it doesn't always provide a lasting solution because previous distresses and cracks eventually make their way up to the new layer of pavement."


As an alternative to these two methods, in-place asphalt recycling continues to gain popularity. Full-depth reclamation (FDR) is a pavement recycling technique in which the existing pavement and some of the existing base layer are broken up and blended to form an improved base for a new asphalt surface. Sometimes an additive is mixed in with the recycled pavement layer to further increase its stability, which is known as stabilized full-depth reclamation (SFDR).

As FDR and SFDR gain popularity, highway engineers need ways to effectively evaluate their properties and correctly apply pavement design guidelines. Few documented field studies have measured material performance, however, so assigning the proper design values to FDR and SFDR pavements is done conservatively.

To provide engineers with more guidance, the Minnesota Department of Transportation (MnDOT) sponsored a U of M study to estimate the proper design values and assess the effects of seasonal temperature changes on these pavements.

"MnDOT uses granular equivalency (GE) to describe stiffness of asphalt and base materials," says Shongtao Dai, research operations engineer with MnDOT's Office of Materials and Road Research. When this project was initiated in 2009, there was no well-defined method to determine GE, he explains, and MnDOT recommended a GE of 1.0 (equivalent to a "class 5" aggregate).


Over three years, the U of M research team led by Labuz evaluated tests performed by MnDOT to determine the stiffness of seven sections of FDR and SFDR county roads in Minnesota. During the spring thaw of each year, tests were conducted daily during the first week of thawing to document seasonal weakening of the pavement's base layer. After the spring thaw period, tests were conducted monthly at each location to capture the pavement strength changes throughout the season.

The study results demonstrate the benefits of SFDR pavements in particular: SFDR pavements were determined to have a higher "stiffness rating" than had previously been assigned by MnDOT, and GE was estimated at about 1.5—meaning less expensive aggregates could beconsidered. In addition, while both pavement types exhibited the seasonal effects typical for asphalt pavements—lower stiffness in the spring than in the summer and fall—most of the SFDR pavements showed improved seasonal stiffness.

"The research has provided guidance and confidence to MnDOT on determining GE values for SFDR materials," Dai says.

Brian Noetzelman, county engineer of Pope County and a member of the project advisory panel, adds that if the GE for SFDR rose from 1.0 to 1.5, it would give 50 percent more carrying capacity to the existing base GE at a minimal cost. "Current 9-ton designs could now be 10-ton designs with the same design structure. What a tremendous savings for counties!"

Reprinted from CTS Catalyst, June 2013.

Quality-of-life study helps MnDOT evaluate performance measures

| No Comments

As part of a study on transportation and quality of life, the Minnesota Department of Transportation (MnDOT) has partnered with researchers from the University of Minnesota's Tourism Center to compare current MnDOT performance measures with quality-of-life factors that matter most to Minnesotans.

The evaluation was designed to help MnDOT ensure alignment between the factors that best predict transportation satisfaction among Minnesota citizens and the indicators MnDOT uses to track and measure its performance. The study team was led by Ingrid Schneider, Tourism Center director, and Karla Rains, director of customer relations at MnDOT.

To conduct the evaluation, the research team first analyzed data collected using surveys and focus groups in a previous phase of the quality-of-life study. The data included information on the categories that contribute to quality of life in Minnesota, the role of transportation, and the specific factors or services within transportation that affect citizens' quality of life.

From these data, the team identified a list of key transportation elements that drive customer satisfaction. Results indicate that the most significant predictors can be grouped into three categories: maintenance/safety, mobility, and transparency. Within those categories, 11 specific items—such as snow and ice removal, road smoothness, commute time, and satisfaction with long-term planning—account for 56 percent of the differences in citizens' transportation satisfaction.

The team then compared the factors most important to Minnesota citizens with MnDOT's current performance measures. Overall findings indicate that these existing measures, which track performance in nine major areas, broadly capture much of what is important for Minnesotans' transportation-related quality of life.

"This was an important key finding for us—we're already measuring and reporting on many of the things that matter most to our customers," Rains says. "It was encouraging and comforting to see that."

In addition to affirming MnDOT's existing measures, the evaluation identified a few gaps, specifically in the areas of safety, the environment, and transparency.

For example, MnDOT typically reports transportation safety in terms of total traffic fatalities and serious injuries from vehicle crashes. However, the quality-of-life study revealed citizen interest in a broader view of traveler safety. As a result, MnDOT plans to include bicycle, pedestrian, and railroad-grade crossing fatality data in future performance measures. "This is already data that we track, but now we plan to add more reporting of fatalities by mode than we have included before," Rains says.

Based on other study-identified topics of importance, MnDOT plans to add new performance measures focused on air pollution and conduct more reporting of information related to public trust. "We continue to use this data as guidance in our planning, and it continues to be useful," Rains says.

"We want to make sure we're listening and measuring ourselves against the things that are most important to our customers."

Reprinted from CTS Catalyst, June 2013.

photo of people getting tickets at light rail station

The Hiawatha light-rail transit (LRT) line began operations in 2004. How has the line affected transit ridership and walking among nearby residents? To get an understanding, U of M researchers conducted a case study of one section of the line in south Minneapolis.

The study, led by Jason Cao, assistant professor in the Humphrey School of Public Affairs, focused on a four-station, 3.8-mile residential section in the middle of the 12-mile Hiawatha line. Cao and his research assistant, Jessica Schoner, compared the section with four control corridors (two urban, two suburban) with similar demographics. The urban corridors resemble the Hiawatha Corridor in terms of built environment and transit access (via comparable bus service); the suburban corridors have curvier roadways and typically require park-and-ride for transit access.

The researchers mailed 6,000 surveys to a random sample of residences in the four control corridors and to residences within a half-mile of the four stations in the Hiawatha Corridor. From their analysis, the researchers drew conclusions in three areas:

Residential preferences of Hiawatha residents

  • In choosing where to live, good transit service and job accessibility are important factors for residents of all areas--both urban and suburban--ranking behind only housing affordability and neighborhood safety and ahead of more than 20 other factors such as high-quality schools.

  • Hiawatha Corridor residents have a stronger preference for transit access and quality than residents of the urban control corridors.

Impacts of the Hiawatha line on transit use

  • Transit use among residents who already lived in the Hiawatha Corridor when the LRT line opened increased substantially for both work and non-work travel--a clear ridership bonus from the line.

  • Transit use by residents who moved into the Hiawatha Corridor after the line opened is similar to that of residents in the urban control areas.

  • Residents in the Hiawatha Corridor use transit three to four times more often than suburban residents do.

The Hiawatha line, the built environment, and pedestrian travel

  • Residents walk to stores more frequently if their homes are near commercial areas and their neighborhoods have adequate population density and a continuous street grid.

  • Residents walk for recreation more frequently if there is a continuous street grid, but population density and proximity to stores are not significant factors.

  • Residents along the Hiawatha line, which has a frequently interrupted street grid, walk for shopping or recreation at the same frequency as bus riders--LRT did not have a distinct measurable impact on walking.

"This study helps confirm the region's transitway investment plan, which seeks to better align transit and land-use planning with the development of sustainable communities," says Metro Transit General Manager Brian Lamb. "It also reinforces that people do make location choices based on transit-related characteristics."

The research was funded by the Transitway Impacts Research Program (TIRP).

Reprinted from the CTS Catalyst, May 2013.

Searching for common ground in the ITS privacy debate

| No Comments

Should your vehicle be able to gather, store, or transmit information about where it's been--or where it's going? On the surface, it seems like a simple question. However, it inevitably gives rise to many others: Who will see the data? How will it be used? Can it be given or sold to a third party? Under what circumstances? Clearly, there are no straightforward solutions or answers in the debate surrounding privacy issues in intelligent transportation systems (ITS).

"The difficulty and complexity of these issues has resulted in an increasingly disconnected public discussion about privacy and ITS," says Frank Douma, a researcher in the Humphrey School of Public Affairs. "In one camp are privacy advocates, and in the other camp are technologists and the ITS industry, who generally view privacy issues as secondary when compared with the tremendous benefits of these technologies. The disconnect often results in the two sides talking past each other, with too little energy spent finding potential common ground."

According to Douma, one cause of this disconnect is a lack of clarity on both sides about the needs, goals, and interests of those involved. To address this divide, a multidisciplinary team of U of M researchers has published a report that sheds new light on the ITS privacy debate by mapping and assessing the interests of all participants. The team was led by Douma and research assistant Tom Garry, and the project was sponsored by the ITS Institute.


The ITS privacy debate involves an interlaced web of participants with multiple interests.

Researchers began their analysis by pinpointing exactly who should be concerned about privacy as ITS technologies are developed and implemented and what their goals are with respect to privacy data. A number of diverse participant groups were identified, including ITS developers, transportation users, the government, data collectors, data users, and secondary users such as marketers and litigants.

"We found few black-and-white divides among participants in the privacy debate," says Douma. "For example, transportation users are not simply pro-privacy, and data collectors are not inherently anti-privacy. Individuals are willing to share their locational data in exchange for real benefits in a variety of circumstances, such as GPS guidance or electronic tolling. However, there are also limits to this willingness."

Because of this nuanced landscape, researchers concluded that while there is no all-encompassing solution to the ITS privacy debate, there are a number of potential avenues and tools for finding common ground. Their recommendations include setting limits on the time data can be retained, prohibiting unrelated secondary use of data, designing ITS systems with privacy in mind, avoiding the collection of personally identifiable locational information when possible, and implementing privacy policies such as the use of clear privacy notices.

"It's also important to remember that the positions of participants in this debate are not entrenched," says Douma. "As technology changes, privacy expectations will also likely evolve as well, such that what may seem important today is less so, and something we are not considering today could be critically important in the future. Consequently, it's very important that this conversation continue in the years to come."

Reprinted from the CTS Catalyst, May 2013.


Center for Transportation Studies

University of Minnesota

200 Transportation & Safety Building

511 Washington Ave SE

Minneapolis, MN 55455

Phone: 612-626-1077

Fax: 612-625-6381


Location & Contact Information