Traffic impacts of Minnesota colleges and universities

University of Minnesota researchers Barbara VanDrasek and John Adams studied the traffic impacts of institutions across the state to find out how their students and employees affect traffic on the local and county levels. The research was supported by CTS.

The researchers note that the traffic generated by colleges and universities can produce impacts at several scales: local, county, and larger commuting area. In the present study, counties were selected as the most appropriate scale of analysis. The study focused on campuses and cities outside the Twin Cities metropolitan area. The research builds on findings from two previous studies that investigated land development and traffic trends for a sample of regional centers and surrounding areas. Examining 27 campus-based cases, the researchers estimated traffic generation rates for different types of schools using trip generation factors created by the Institute of Transportation Engineers. In their final report, the researchers also discuss societal trends likely to affect schools as traffic generators and speculate about implications for future transportation planning.

College and University Campuses in Greater Minnesota as Traffic Generators (CTS 09-17) is available from the CTS Web site.

Intelligent Transportation Systems

New signal control strategy for isolated intersections

Smoothing out traffic flow through isolated rural and suburban high-speed intersections is the latest traffic management challenge taken up by researchers in the University of Minnesota’s Department of Civil Engineering. Assistant professor Henry Liu and graduate student Sundeep Bhimireddy developed a traffic signal control strategy that reduces traffic flow disruption occurring when groups of vehicles traveling at highway speeds are forced to stop frequently at isolated intersections. The research was funded by the Minnesota Department of Transportation.

According to the final research report, most of the rural or suburban high-speed isolated intersections have higher traffic volumes on the major approach compared to the minor approach. Often, these intersections are not close enough to one another to provide coordination and not far enough to disperse vehicle platoons completely on the major approach. These vehicle platoons on the major approach are forced to stop frequently due to conflicting calls placed by few vehicles on the minor approach. As a result, these intersections operate poorly, especially during peak periods.

In addition, advance warning flashers are used at these intersections to provide advance warning of end of green to the motorists. The conventional method uses a technique known as “trailing overlap green” that holds the green for a fixed time after gap-out. This trailing overlap green replaces the existing dilemma-zone protection provided by loop detectors installed near the intersection, and also increases delay on the minor approach.

Liu and Bhimireddy developed an integrated system that provides both platoon progression and advance warning of end of green and evaluated its performance in terms of delay, stops, and advance warning time. Cabinet-in the-loop tests were performed using a real-world scenario. These study results showed a 50 percent reduction in delay and stops on the major approach with platoons, and total intersection delay and stops were reduced by as much as 20 percent. The system was also successful in providing advance warning to the motorists by predicting gap-outs 7 to 8 seconds earlier in the majority of the cases.

Development of a Platoon-Priority Control Strategy with/out Smart Advance Warning Flashers for Isolated Intersections with High-Speed Approaches (Mn/DOT 2009-23) is available from the ITS Institute Web site.

Transit, Bicycling, and Walking

TCRP research publications available online

The federal Transit Cooperative Research Program (TCRP), administered by the Transportation Research Board, provides practical transit research to address technical and operational issues. TCRP emphasizes putting research results into the hands of organizations and individuals that can use them to solve problems.

Recent TCRP publications include:

• Transit, Call Centers, and 511: A Guide for Decision Makers (TCRP Report 134)
• Passenger Counting Systems (TCRP Synthesis 77)
• Uses of Fees or Alternatives to Fund Transit (TCRP Legal Research Digest 28)
• First Amendment Implications for Transit Facilities: Speech, Advertising, and Loitering (TCRP Legal Research Digest 29)
• Appendixes to TCRP Report 135: Controlling System Costs: Basic and Advanced Scheduling Manuals and Contemporary Issues in Transit Scheduling (TCRP Web-Only Document 45)

Transportation Infrastructure

Subsurface drainage manual for pavements created by researchers

Excess water under roadways often weakens the roads’ foundation structures and eventually causes deterioration of the road surface. The result is millions of dollars in repair costs annually. A wide variety of products and techniques have been created to address the problem of excess subsurface water, but these measures must be selected and implemented with care to achieve optimum performance.

To help maintenance agencies select the right subsurface drainage treatments for their particular needs, Department of Bioproducts and Biosystems Engineering research associates Dario Canelon and Caleb Arika worked with professor John Nieber to create a manual that collects and synthesizes information from many sources. The research was sponsored by the Minnesota Local Road Research Board and the Minnesota Department of Transportation.

The manual includes an overview of subsurface drainage structures, as well as guidelines for selecting, designing, constructing, and maintaining drainage structures. Additional appendices provide recommended procedures, design plans, charts and tables, and additional examples. The information is intended to address pavement types and situations commonly found in Minnesota.

Subsurface Drainage Manual for Pavements in Minnesota (Mn/DOT 2009-17) is available on the CTS Web site.

Safety

Register now for 2009 Toward Zero Deaths conference

This conference provides a forum for sharing information on best practices in engineering, enforcement, education, and emergency medical and trauma care and for identifying new approaches to reducing the number of traffic fatalities and life-changing injuries on Minnesota roads.

The conference is sponsored by the Minnesota Departments of Public Safety and Transportation and the Minnesota Toward Zero Deaths Program. The conference is hosted by the Center for Transportation Studies and is facilitated by the College of Continuing Education.

More information and online registration are available on the TZD Web site.

Upcoming Events

September 25
Warren Seminar for the Robert Dexter Memorial Scholarship: Fatigue and Corrosion influence on the Durability of Steel Bridges, University of Minnesota, Minneapolis, MN

September 28-29
AirTAP Fall Forum, Mankato, MN.

October 28-29
Toward Zero Deaths Annual Conference, Duluth, MN