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Sidewalk replacement contributes to Minneapolis tree loss

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sidewalk.jpgLast June a windstorm toppled about 1,800 trees in Minneapolis. Many of the fallen trees were in boulevards (the area between sidewalks and streets) rather than in yards. This raised concerns that recent sidewalk replacement—and resulting severed tree roots—had been a factor.

To better understand the higher-than-normal losses, the Minneapolis Park and Recreation Board (MPRB) turned to the U’s Urban Forestry Outreach, Research and Extension lab. “The MPRB Forestry Department has partnered with the University of Minnesota for years,” says Ralph Sievert, MPRB forestry director. “When this study presented itself, we did not hesitate to ask the lab to participate.”

Led by forestry department professor Gary Johnson, the lab studied damaged and undamaged trees along the storm’s path. The data set included 3,076 trees, of which 367 were total failures (tipped or partially tipped) due to the storm.

“The major finding is that replacing the sidewalk increased the odds of root failure by 2.24 times,” Johnson says. For example, when no replacement work was done, the average linden had a 10.6 percent chance of root failure; with sidewalk replacement, this increased to 21.0 percent.

When combined with replacement work, tree species was also a significant factor. Linden trees were most likely to fail, followed by ash, maple, and elm. “Essentially, when replacement work was done near any one of these trees, the rate of failures more than doubled,” Johnson says.

“Now we have a great opportunity to make improvements,” Sievert says. “I’m anticipating this leading to safer, healthier trees with fewer instances of infrastructure damage.”

Read the full article in the June issue of Catalyst.

Primary seat belt law continues to save lives, money

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seatbelt.jpgMinnesota’s primary seat belt law continues to save lives and reduce serious injuries more than four years after being passed, according to a study by researchers at the U of M’s Humphrey School of Public Affairs.

The study examined Minnesota crash data collected from June 2009 (when the law was implemented) through June 2013 and compared it to expected data based on crash trends over time. Findings indicate that there were at least 132 fewer deaths, 434 fewer severe injuries, and 1,270 fewer moderate injuries than expected during this time.

According to the researchers, the safety benefits of the law translate into a savings of at least $67 million in avoided hospital charges, including nearly $16 million in taxpayer dollars that would have paid for Medicare and Medicaid charges.

The study was sponsored by the Minnesota Department of Public Safety and led by Humphrey School research fellow Frank Douma and Nebiyou Tilahun, a U of M graduate now on the faculty at the University of Illinois-Chicago.

The researchers also examined seat belt use data and survey results that measured support for the law. Findings show that support increased from 62 percent just before the law was passed to more than 70 percent in 2013, while the percentage of Minnesotans buckling up was at an all-time high of nearly 95 percent in 2013. This shows that some people are wearing their seat belts even though they don’t support the law.

When this increased seat belt use is combined with the reduction in fatalities and injuries, it further demonstrates that people are surviving—and even walking away from—crashes that may have had different results if the primary seat belt law had not been in effect.

Read the full article in the June issue of CTS Catalyst.

The Metro Transit Green Line LRT opens on Saturday, June 14th. This $957 million transit project, which began in 2010, runs from Target Field in Minneapolis through the heart of the University of Minnesota campus to Union Depot in St. Paul. The U of M is a major destination along the new line. Along with several new construction and redevelopment projects, Washington Avenue on the East Bank has been transformed into a transit-pedestrian mall reserved for trains, buses, pedestrians, and cyclists.

The following University of Minnesota researchers are available to provide a variety of perspectives on this major transit project and what it means for the Twin Cities:

  • Transit and economic development: Yingling Fan, assistant professor at the Humphrey School of Public Affairs and a leading researcher for the Transitway Impacts Research Program
  • Transit and accessibility: Andrew Owen, director of the Accessibility Observatory
  • Transit and traffic flow: John Hourdos, director of the Minnesota Traffic Observatory
  • Transit and multimodal travel: Greg Lindsey, professor at the Humphrey School of Public Affairs

To schedule an interview with any of these experts, please contact: Michael McCarthy, Center for Transportation Studies, mpmccarthy@umn.edu, 612-624-3645.

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When it comes to crashes, right-angle collisions are among the most dangerous for vehicle occupants. These crashes often occur at stop-controlled intersections when drivers fail to stop, and traffic engineers are increasingly installing flashing LED stop signs—normal octagonal stop signs with flashing lights mounted on the corners—in an attempt to improve intersection safety.

A study by researchers from the U’s civil engineering department and Minnesota Traffic Observatory aims to give traffic engineers a clearer picture of the safety benefits of flashing LED stop signs. The research team conducted a two-pronged investigation of the signs’ safety effects: a statistical study to estimate crash reduction and a field study looking at drivers’ behavior changes after the installation of a flashing LED stop sign.

For the statistical study, the team compared the frequency of crashes after the installation of flashing LED stop signs at 15 intersections with a prediction of what the crash frequency would have been without the signs. Findings estimate that the installations reduced right-angle crashes by about 42 percent.

For the field study, researchers collected video data before and after the installation of a flashing LED stop sign in Chisago County, Minnesota. They then analyzed the video to determine driver stopping behavior and vehicle deceleration rates.

According to principal investigator Professor Gary Davis, there was no change in the proportion of clear stops to clear non-stops when drivers didn’t encounter opposing traffic. However, the proportion of clear stops increased after installation of the sign when opposing traffic was present.

The team used their findings to create a decision-support tool that can help traffic engineers decide where to place flashing LED stop signs. The tool can be used to determine whether right-angle crashes are a problem at a selected intersection and to predict the crash reduction expected from installing the flashing sign.

Read the full article in the May issue of Catalyst.

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People love to walk and bike—for relaxation, for exercise, to get places like school, work, and stores. Biking and walking have increased significantly in the Twin Cities metro area during the past decade, and these activities are catching fire statewide.

U of M researchers have partnered with the Minnesota Department of Transportation, the Minnesota Department of Health, and several other state and local agencies to develop general guidance and consistent methods for counting all these bicyclists and pedestrians in Minnesota. Their work was honored with the 2014 CTS Research Partnership Award, which was presented at the CTS Annual Meeting and Awards Luncheon. The award recognizes research teams that have drawn on the strengths of their diverse partnerships to achieve significant impacts on transportation.

The research team, led by Professor Greg Lindsey of the Humphrey School of Public Affairs, developed tools and methods to count and analyze bike and pedestrian traffic using a mix of manual and automated methods.

Results from the counting initiative are allowing policymakers and planners to make data-driven decisions about transportation investments.

Work is continuing under the initiative. A MnDOT project, which will conclude in 2015, uses automated technologies for counting bicycles and pedestrians on trails, bike lanes, sidewalks, and shoulders in various urban and rural locations in Minnesota.

MnDOT also is considering how to incorporate such nonmotorized traffic data into its existing traffic database. The researchers recommended that MnDOT coordinate statewide counts and work with local agencies to establish a network of automated monitoring sites across the state.

In addition to supporting state goals, this research also is contributing to federal traffic monitoring standards.

Read the full article in the May issue of Catalyst.

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Despite more similar roles at work and home than ever before, U.S. men and women continue to have different travel behavior. Historically, employed men have spent more time traveling to work and less time on household and family support trips than women.

While this difference is well-documented, explanations for the difference vary widely: some theories say it’s due to biologically driven differences in gender, while others attribute it to socially constructed gender roles or to gendered structural contexts such as labor market segregation and economic inequality.

While much research has examined these theories, few studies have tested their validity based on evidence—which prompted U of M researchers to examine the theories more deeply in attempt to effectively address gender equity issues in transportation policy.

The researchers set out to test the competing theories by analyzing publicly available data from the American Time Use Survey (ATUS) in various ways across groups of workers with different types of family structures.

First, they tested the theory that travel behavior differences were based on biologically driven gender differences. “If this theory was true, travel differences between men and women could be applied across all population groups regardless of family structure, but this was not the case,” Fan explains. “We found that single female workers and single male workers exhibit no significant difference in travel behavior.”

Next, the team studied the impact of gendered structural contexts, such as women’s greater presence in pink-collar occupations and significantly lower earnings. The team found moderate support for this theory. “These factors are associated with shorter work travel time among some—but not all—family structures,” Fan says.

Researchers did find strong support, however, for the theory that socially constructed gender roles explain travel behavior differences. “We discovered that while marriage alone doesn’t differentiate travel behavior between men and women, parenthood does have a significant impact,” Fan says. “Interestingly, we found that even being the sole breadwinner does not insulate mothers from socially constructed gender roles—female breadwinners in married single-worker households with children have shorter work commutes and more household support travel than male breadwinners in the same family structure.”

According to the researchers, these findings have important implications. First, policies to minimize auto travel (for environmental purposes, for example) may be unfair to women who wish to reach more job possibilities through longer commutes. In addition, the findings highlight the importance of incorporating parenthood as a prime variable in understanding the gender and mobility connection.

Finally, this research provides insights on how future growth or decline in specific family structures may shape travel demand. “As childless households continue to grow in relation to households with children, it’s possible that fewer female workers will be confined by short work commutes and may choose to spend more time commuting to more desirable jobs, placing new demands on the transportation system,” Fan says.

The research was funded in part by a Minnesota Population Center Program Development Grant.

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The discussion and debate about automated speed enforcement in many states—including Minnesota—is both complex and puzzling. On one hand, studies have shown that automated speed enforcement (ASE) increases roadway safety when deployed in certain settings, and public opinion polls show Minnesotans overwhelmingly support ASE in certain locations.

On the other hand, only 14 states and Washington, D.C., employ ASE; Minnesota is one of the 36 states that do not use automated speed enforcement. The perceived lack of public support is often cited as the primary reason ASE isn’t used in more states.

Prompted by the gap in Minnesota between state policy and the safety benefits and strong support for ASE, researchers at the Humphrey School of Public Affairs designed a study to investigate scenarios for an ASE pilot program in work and school zones in Minnesota.

First, the research team documented the legal and political environment surrounding ASE in Minnesota and analyzed available data for speed-related crashes in Minnesota school and work zones. Next, the researchers investigated and cataloged the possible solutions to a number of considerations and questions involved in developing an ASE pilot project.

Finally, researchers set out to develop a “blueprint” of preferred scenarios for ASE in Minnesota—and came face-to-face with several obstacles, such as making decisions about design elements while weighing difficult political and policy issues surrounding public acceptance, operational challenges and cost issues, and effectiveness.

Despite these obstacles, policy experts say an ASE program in Minnesota is possible if government stakeholders and policymakers agree that ASE is a worthwhile investment.

Read the full article in the April issue of Catalyst.

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The new Roadway Safety Institute, a $10.4 million regional University Transportation Center (UTC) established in late 2013, will conduct a range of research, education, and technology transfer initiatives related to transportation safety. Led by the University of Minnesota, the two-year consortium will develop and implement user-centered safety solutions across multiple modes.

The Institute will be a focal point for safety-related work in the region, which includes Minnesota, Illinois, Indiana, Michigan, Ohio, and Wisconsin. Other consortium members are the University of Akron, University of Illinois at Urbana-Champaign, Southern Illinois University Edwardsville, and Western Michigan University.

Max Donath, professor of mechanical engineering at the U of M, serves as the new Institute’s director. In this month’s Catalyst, Donath shared his vision for the Institute.

According to Donath, the Institute will focus on addressing regional traffic safety priorities, educating the public, and attracting more professionals to the safety workforce by connecting with students.

Research topics will focus on two key areas, Donath said: high-risk road users and traffic safety system approaches. The goal of this work is to prevent the crashes that lead to fatalities and injuries on the region's roads.

One unique Institute effort will involve working with American Indian communities in the region to explore and address the unusually high number of motor vehicle crash fatalities on tribal lands.  "Our research will work to better understand why this is happening and to develop more effective solutions," Donath said.

Read the full Q&A in the April issue of Catalyst.

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Photo: SRF Consulting Group, Inc.

There’s broad agreement that the U.S. transportation system cannot continue to be funded with existing financing and revenue-generation methods. What’s unclear, however, is how to pay for highway projects in the future. The current transportation funding system emphasizes user fees, but there is growing interest in alternative funding strategies. One promising strategy is value capture, which aims to recover the value of benefits received by property owners and developers as a result of infrastructure improvements.

In recent years, University of Minnesota researchers have helped lead the way in value capture research with a series of reports identifying value capture strategies. In a newly published study, the research team applied their previous work to a real-world scenario, with impressive results.

The new research, sponsored by the Minnesota Department of Transportation, focused on the planned development of Trunk Highway 610 (TH 610) in Maple Grove, Minnesota—a stretch of planned state highway delayed for years by state transportation funding shortages. Researchers set out to discover how the value of the enhanced accessibility provided by the planned improvements could be predicted and captured to help fund the project’s completion.

To accomplish their goal, researchers first defined a study area of about 10 square miles surrounding the unfinished highway segment. Then, they modeled property values based on five factors using parcel-level data. This model was designed to isolate the so-called “highway premium” by controlling for other factors that affect land value including water views, open space, railroads, transit stops, and existing highway exits. Using this model, researchers found significant evidence that the completion of the highway could lead to an over $17 million increase in property value.

Researchers expect these findings to have significant benefits for the TH 610 project and beyond.

Read the full article in the March issue of Catalyst.

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Nearly every time a highway or airport expansion is proposed, transportation planners face opposition from residents who fear the increased noise levels in their homes and businesses. Traffic noise is often mitigated with physical noise barriers, but the large, thick walls often draw opposition as well.

A new technology developed by University
 of Minnesota mechanical engineering professor 
Rajesh Rajamani as part of 
a research project funded
 by the National Science
 Foundation could soon
 provide a nearly invisible
 solution for transportation 
noise cancellation—and 
give transportation planners another tool for overcoming project opposition.

Noise enters homes close to airports and highways primarily through windows, and windows can transmit ten times the sound energy as walls can, says Rajamani. With this in mind, researchers set out to reduce the amount of transportation noise transmitted through windows.

To accomplish this goal, researchers created a method of active noise control for windows. Active noise control works by using speakers to generate a sound wave that is a mirror image of the undesirable sound wave. Superimposing an "anti-noise" wave of the same amplitude as the undesirable noise wave results in a reduced decibel level of noise in the environment.

The research team began by designing thin, transparent speaker panels to fit in the empty space between the two panes of a double-pane window. Then, the researchers tested the effectiveness of the new speakers, using them to cancel out undesirable transportation noise from outside the home while preserving the desirable noise from inside the home.

In addition to mitigating traffic noise, this new technology offers other surprising benefits. Researchers have found that the "smart window" speakers can actually be used as home audio speakers without losing any of their noise-control benefits.

Read the full article in the February issue of Catalyst.

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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

E-mail: cts@umn.edu

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