With as many as three billion more people expected to live in cities by 2050, there’s renewed interest in a topic often taken for granted: infrastructure. Many are wondering if there are options better than vast highways, elaborate power grids, and complex underground water systems. And cities are already trying localized, “distributed” systems such as community solar power, rain gardens, bike sharing, and urban farms. But what should such systems look like? How should they work? And how should we measure their impact—on efficiency and cost? What about their impact on people’s health and happiness?
Researchers from across the globe are asking such questions as part of a massive four-year effort to rethink urban infrastructure. Knit together in the sprawling Sustainable Healthy Cities network, they are attempting to provide the analyses needed to understand the effects of decisions cities have already made as well as envision what cities might do in the future.
The network, supported by a $12 million grant from the U.S. National Science Foundation, is anchored at the University of Minnesota. CTS Scholar Yingling Fan, an associate professor in urban and regional planning at the Humphrey School, is a co-principal investigator.
For most road crews, repairing potholes is an essential and highly visible duty. Choosing the best or most cost-effective pothole repair method, however, has remained a complicated puzzle.
“Selecting the appropriate patching method and materials varies depending on several factors, including the size of the pothole and its location on the roadway,” says Manik Barman, an assistant professor with the University of Minnesota Duluth (UMD) Department of Civil Engineering. “Patching methods and materials also face seasonal challenges in Minnesota when asphalt plants shut down for the winter, turning cold-weather repairs into short-term fixes.”
To help solve this puzzle, the Minnesota Department of Transportation funded research to help road crews choose patching methods that match specific repair conditions. UMD researchers explored patching tools, materials, and methods to identify which ones were most appropriate for specific pothole conditions, road locations, and time of year. They also evaluated the effectiveness of different methods based on durability, road safety, ride quality, and driver satisfaction.
Members of the public often hear news about the deteriorating state of the nation’s infrastructure, but in general they are unaware of the efforts and costs required to maintain and operate the transportation systems they rely on every day.
In a recent study, U of M researchers sought to better understand stakeholder attitudes, knowledge, and engagement about financing for local road system management. “It’s important for people to be informed and to be listened to, and to have their opinions taken into consideration in decision making,” says Guillermo Narváez, a former research associate with the Humphrey School of Public Affairs and the project’s principal investigator. “This approach very often leads to better outcomes than non-participative decisions.”
Narváez collaborated with Professor Kathryn Quick, also with the Humphrey School, for the project. The research team collected and analyzed data about the general climate of stakeholder knowledge and attitudes toward road financing. Data were collected through media analysis, case studies, interviews, and surveys of county government leaders.
While people generally support investing in transportation infrastructure, they fiercely oppose increases in user fees or taxes to support this investment. This funding problem is further compounded by the opaqueness of transportation revenue mechanisms such as the gas tax, which makes it difficult for the traveling public to easily discern how much they pay for infrastructure and what value they derive from it.
In the opening session of CTS’s annual Research Conference last month, Joung Lee, policy director at the American Association of State Highway and Transportation Officials (AASHTO), examined the latest direction in infrastructure funding at the federal level, offered examples of innovation happening at the state level, and discussed policy and political considerations when it comes to transportation revenue and financing tools.
With the aim of reducing congestion on the Twin Cities’ highly traveled I-35W corridor between the Minnesota River and I-94, the Minnesota Department of Transportation (MnDOT) began a major set of I-35W improvements in 2009 as part of the Federal Highway Administration’s Urban Partnership Agreement (UPA). Among the improvements was the addition of a priced dynamic shoulder lane (PDSL) on parts of the 17-mile stretch of highway; however, following the opening of these improvements, the frequency of rear-end crashes increased in certain sections—especially in the PDSL regions.
To untangle the underlying causes of this increase, MnDOT enlisted the help of researchers in the Department of Civil, Environmental, and Geo- Engineering. “Our primary objective was to determine if these increases were direct effects of the improvements or if they were due to changes in the traffic conditions,” says Professor Gary Davis, the principal investigator. “MnDOT was interested in extending some or all of these improvements to other corridors but needed to know what the safety impacts were to aid its decision making.”
This summer, U of M researchers are bringing bridge girders into their lab to help MnDOT evaluate a repair method that could ultimately reduce traffic interruptions caused by infrastructure repairs.
The salting of bridge and roadway surfaces during Minnesota winters can create highly corrosive conditions that result in damage to bridges. Such was the case with the Trunk Highway 169 Nine Mile Creek Bridge near Edina and Minnetonka, where leaking expansion joints caused corrosion to elements responsible for the strength of bridge girders: shear reinforcement, prestressing strands, and the surrounding concrete. MnDOT repaired the damaged girder ends in 2013 by encasing them using a system of steel dowels, additional shear reinforcement, and sprayed concrete. MnDOT was able to make the repairs without traffic interruption.
Now, the bridge is being replaced, and U of M professor Carol Shield and her team of researchers are evaluating the effectiveness of the 2013 repair. The researchers’ goal is to determine if the repair strengthened the corrosion-damaged girders to a level similar to noncorroded girders. If proven effective, MnDOT could use this type of repair to lengthen the useful life of existing bridges and save travelers time and frustration caused by repair-related traffic delays.
CTS scholar Cathy French and three U of M students were honored by WTS Minnesota at the organization’s 2017 Scholarships and Recognitions Luncheon on April 27.
French, a CSE Distinguished Professor in the U’s Department of Civil, Environmental, and Geo- Engineering, received the 2017 Woman of the Year Award. The annual award recognizes women who are outstanding role models in transportation.
U of M students Maria Wardoku, Ella Rasp, and Claire Warren received scholarships that recognize women pursuing undergraduate and graduate degrees in transportation-related fields.