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.
In a recent project, the Alaska Department of Transportation used a byproduct of Minnesota’s taconite mining industry for a section of the Alaska Glenn Highway.
The taconite byproduct—Mesabi sand—serves as the aggregate of a sand-seal treatment for a 4,600-foot stretch of the highway just north of Anchorage. Sand seals are an application of a sealer, usually an emulsion, immediately followed by a light covering of a fine aggregate (the sand).
Larry Zanko, senior research program manager of the Natural Resources Research Institute at the University of Minnesota Duluth, was the on-site representative for the taconite sand analysis.
Last month, CTS debuted two videos about the many contributions U of M researchers have made—and are still making—in traffic operations and pavement design.
The videos are one of the ways CTS is marking 30 years of transportation innovation. Our goal is to show how research progresses over time—from curiosity to discovery to innovation. The videos also show how U of M research meets the practical needs of Minnesotans in the Twin Cities metro and throughout the state.
Transportation funding continues to be a contentious issue in Minnesota: Are we spending enough, too little, too much? One way to help answer that question is to compare spending with other states.
“A simple comparison, however, may not accurately reflect the real level of transportation funding across the states,” says Jerry Zhao, an associate professor in the Humphrey School of Public Affairs. “States face different levels of demand and costs due to different geographic, demographic, or labor market conditions.”
To better understand the factors that influence the transportation funding level, Zhao and Professor Wen Wang at Rutgers University developed a cost-adjusted approach to systematically compare highway expenses among states. They found that while Minnesota spends more than average on highways, its spending level actually ranks low in cost-adjusted measures.