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Current Issue | Previous Issues | Subscribe November 2004 - Vol. 2 No. 10

Policy & Planning

Case studies offer perspectives on suburban expansion

Every suburb has a story. These stories hold important lessons about the effects of land use and transportation planning decisions. A new research report from the Transportation and Regional Growth Study presents four case studies of suburbs around the Twin Cities, giving planners and policymakers an opportunity to see dynamic relationships evolve over time.

Report authors Barbara VanDrasek and John Adams of the University of Minnesota’s Department of Geography are adept at tracing the dynamics of metropolitan areas in time and space. Their previous contributions to the TRG study include six previous research reports.

The new report focuses on the local property tax and its relationship to municipal revenue generation and service provision, as well as on Minnesota’s K-12 education finance system. In the context of suburban development, these factors are intertwined with the development of transportation systems and land use patterns.

Case Studies of Development in the Minneapolis-St. Paul Metropolitan Area is available from the Transportation and Regional Growth Study Web site at www.cts.umn.edu/trg/research/reports/TRG_14.html.

Intelligent Transportation Systems

What are they looking at?

Understanding exactly what drivers are doing as they operate their vehicles is an important goal for intelligent transportation systems researchers. Because driving involves many sub-tasks and takes place in a complicated and constantly changing environment, finding out what drivers are doing is a challenge. But work at the University of Minnesota’s Department of Computer Science and Engineering could help researchers get a clearer picture.

Graduate student Eric Wahlstrom, research associate Osama Masoud, and professor Nikolaos Papanikolopoulos developed computer software that analyzes a series of images from a camera in the vehicle to determine the direction of the driver’s gaze or whether the driver is using a particular vehicle control.

This research relied on the Framework for Processing Video (FPV), original software developed by Masoud at the University of Minnesota. Masoud and Papanikolopoulos have made numerous contributions to intelligent transportation systems research at the University, and have been selected as CTS Faculty & Research Scholars.

To determine what a driver is looking at, the researchers realized, their system did not need to create a complete representation of a face. Instead, it first locates the lips, by matching a range of appropriate colors. Working from the mouth, the system then finds the locations of the eyes. Subsequent steps determine the position of the pupils and the relationship of each pupil to the corners of the eye. These measurements allow the system to determine not only the direction of the gaze, but roughly how far away the eyes are focused.

Other recent experiments using the system focused on detecting when a driver was using the control panel of the car stereo. A second camera (mounted outside a stationary vehicle) was used to monitor the control area; software detection algorithms determined whether the driver’s hand was active in the control area.

Future enhancements envisioned by the researchers include expanding the system to allow it to categorize different driver behaviors and track them over time, and improving the system’s error correction capabilities. The addition of a robust eye-tracking mechanism is also a possibility.

Monitoring Driver Activities, a final research report on the project, is available on the CTS Web site at www.cts.umn.edu/pdf/CTS-04-05.pdf (2.0 MB).

Transportation Infrastructure

Better joints in concrete pavements

Joints between sections of portland cement concrete roadway, necessary to relieve thermal expansion and contraction, also have to deal with load transfer between sections due to constant pressure from heavy vehicles. Currently, steel dowel bars are the standard for transferring loads between slabs; however, these bars are expensive to retrofit and prone to maintenance problems due to corrosion.

At the Department of Civil Engineering, researchers have used accelerated pavement testing procedures to evaluate the potential of experimental dowel bar retrofit designs to avoid these problems. Graduate student Trevor Odden and faculty members Arturo Schultz and Mark Snyder (now with the Concrete Paving Association of Minnesota) tested innovations including fiber reinforced polymer dowels, grouted stainless steel pipe dowels, and a change in the geometric configuration of the typical design.

The team’s experiments utilized the Minnesota Accelerated Loading Facility (Minne-ALF) test platform, located in Minneapolis. Minne-ALF is a full-scale apparatus that allows researchers to simulate the effects of heavy vehicles passing over test slabs under controlled conditions. Researchers can test multiple test sections under a variety of loading conditions.

Based on their experiments, the researchers developed several recommendations about the potential future use of these new dowel bar designs, and additional research that may be necessary to confirm and expand their results. With constant demand from road users for roadways that require less maintenance and still offer a quiet, comfortable ride, this research shows how innovative research can pay off on the road.

The final research report in two volumes, Performance Testing Of Experimental Dowel Bar Retrofit Designs (Mn/DOT 2004-17A & 2004-17B), is available from the Minnesota Department of Transportation Web site at www.research.dot.state.mn.us/detail.asp?productID=1938 and www.research.dot.state.mn.us/detail.asp?productID=1939.

Revised best practices for low-volume road construction and maintenance

A revised best practices manual for the construction and maintenance of low-volume roads has been published by the Minnesota Department of Transportation. The new document, developed by a team of researchers led by Eugene Skok of the University of Minnesota’s Department of Civil Engineering, updates the low-volume roads manual originally published in 2002.

Topics covered in the revised manual include the mechanistic-empirical MnPAVE procedure for hot-mix asphalt (HMA) pavement design, methods for traffic estimates, subgrade (embankment) soils and materials (including the use of geosynthetics and alternative fill materials such as shredded tires and wood chips), and pavement construction techniques, including granular materials and aggregate bases. The information presented is optimized for Minnesota hot-mix asphalt applications.

This updated manual is a valuable resource for road maintenance agencies in Minnesota, as well as an informative survey of Minnesota’s highly developed low-volume road practices for transportation agencies in other states.

Best Practices for the Design and Construction of Low-Volume Roads (Revised) (Mn/DOT 2002-17REV) is available from the Mn/DOT Web site at www.research.dot.state.mn.us/detail.asp?productID=1932.

Transportation & the Environment

Controlling invasive vegetation in wetland restorations

When performing wetland restorations required by transportation system development, control of invasive vegetation is one of the thorniest obstacles to success. Researchers in the University of Minnesota’s Department of Horticultural Science offer best management practices for dealing with one particularly troublesome species in a new report published by the Minnesota Department of Transportation.

Carrie Reinhardt and Susan Galatowitsch studied reed canary grass (Phalaris arundinacea), a fast-growing perennial plant that often colonizes restored prairie pothole wetlands. Left unchecked, reed canary grass can take over and preclude colonization by typical sedge meadow species that are appropriate for the restored habitat.

A large-scale field experiment carried out by the researchers demonstrated that a combination of late-season herbicide application to maximize rhizome mortality and burning to reduce the number of seeds available for regrowth. However, they caution that reduction of this species is a long-term process, complicated by the fact that reed canary grass is often cultivated for animal forage.

Best Management Practices for the Invasive Phalaris arundinacea L. (Reed Canary Grass) in Wetland Restorations is available on the Mn/DOT Web site at www.research.dot.state.mn.us/detail.asp?productID=1945.

Upcoming Events

Visit the CTS Web site, www.cts.umn.edu/events, for more comprehensive event information.

December 3, 2004
CTS Annual Freight and Logistics Symposium, Four Points Sheraton Hotel, Minneapolis. Contact Heather Dorr, 612-625-5267, hdorr@umn.edu or visit the Freight & Logistics Symposium Web page.

December 7, 2004
Proactive Crash-Prevention Solutions, Advanced Transportation Technologies Seminar Series. View more information.

February 10, 2005
CTS Winter Luncheon, Radisson Hotel Metrodome, Minneapolis. Visit www.cts.umn.edu/events/luncheon/index.html or contact Katie Kjeseth, 612-624-3708, kkjeseth@cce.umn.edu.

February 17, 2005
Minnesota Pavement Conference, Continuing Education Conference Center (formerly Earle Brown), St. Paul. Visit www.cts.umn.edu/events or contact Teresa Washington at 612-624-3745, e-mail twashing@cce.umn.edu.

April 26-27, 2005
16th Annual CTS Transportation Research Conference, RiverCentre, St. Paul. Contact Katie Kjeseth, 612-624-3708, kkjeseth@cce.umn.edu or visit the CTS events calendar.