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Current Issue | Previous Issues | Subscribe February 2008 - Vol. 6, No. 2

Policy & Planning

Research completed for AIA transportation design study

In a time of limited resources at every level of government, communities need to ensure that the transportation projects in which they invest not only increase connectivity and access, but also bring about a wide array of community benefits.

In 2006, the American Institute of Architects (AIA) selected CTS to conduct a pioneering research study to explore how well-designed transportation projects can enhance communities. Results of this research are now available in a series of reports on the study’s Web site: www.movingcommunitiesforward.org.

To address the interdisciplinary issues raised by the study—named Moving Communities Forward—CTS assembled and led a research team drawn from multiple fields. Research funding was allocated to five projects:

• Promoting Economic Development: John Adams, Hubert Humphrey Institute of Public Affairs, and Barbara VanDrasek, Department of Geography
• Protecting Public Health, Safety, and the Environment: John Carmody and Virajita Singh, Center for Sustainable Building Research
• Community Identity, Vision, Aesthetic, Architectural Design, Cultural and Scenic Benefits: Ann Forsyth, Metropolitan Design Center (now with Cornell University )
• Public Participation Processes, Public-Private Outcomes: Carissa Schively Slotterback, Hubert H. Humphrey Institute of Public Affairs
• Traffic Safety Methodologies: Gary Davis, Department of Civil Engineering

A sixth project, by Lance Neckar of the Department of Landscape Architecture, synthesized the study’s key findings into a single document highlighting major themes and recommendations. Neckar also assisted CTS director Robert Johns in providing overall direction for the project.

The research team employed a case study-based approach, analyzing nearly 30 transportation projects across the nation that represent a broad spectrum of regions, demographics, and project types.

Using the case studies, the team identified key principles and practices that communities, transportation officials, designers, and policymakers can use—in the context of their unique situations and environments—to realize multiple enhancements to their communities. The research shows that in many cases, a small change in the design process, or the addition of relatively inexpensive or less intrusive design strategies, can reap large rewards.

Funding for the study was derived from a grant to the American Institute of Architects from the Federal Highway Administration, authorized by Congress in the 2005 federal transportation act, SAFETEA-LU.

CTS has also begun developing a Moving Communities Forward Web site with the AIA as part of a coordinated outreach effort designed to share the research findings and recommended practices with transportation and design professionals, policymakers, and the public.

Selected findings from Moving Communities Forward:

• Integrated design from the outset of a project helps address the full spectrum of challenges.
• Participatory processes and structures build constituencies for design solutions.
• Visualization tools provide critical support and add transparency to the citizen engagement process.
• Human-scaled structures and spaces give intense, multimodal development a sense of place.
• Clearly marked and connected transportation modes make multimodal systems easier to use.
• Durability and flexibility create places that are sustainable and meet future challenges.

Complete research reports are available on the project’s Web site.

Intelligent Transportation Systems

Haptic feedback research explores driver cognition issues

Editor’s note: an extended version of this article appeared in the Winter 2007 ITS Institute Sensor newsletter.

Only a few decades ago, catastrophic failure of critical components was a common cause of automobile crashes. Broken tie-rods sent cars hurtling into ditches; brake systems failed suddenly under the strain of mountain driving. Today, improvements in automotive engineering have greatly reduced the number of crashes caused by mechanical failure while driving. So why are so many people still losing their lives every year in automobile crashes?

Statistics show that more than 40,000 Americans die every year on the road—that adds up to more than 650,000 deaths since 1990. And if current trends continue, driving-related incidents will become the third leading cause of death in this country by 2020, up from ninth in 1990.

"These numbers are simply staggering," says human factors researcher Michael Manser of the ITS Institute's HumanFIRST Program.

One explanation for this apparent paradox is that while engineers have been very successful in making vehicles safer, drivers remain largely unchanged. Today, driver error may be as significant as mechanical failures. And with the myriad electronic controls and options present in today's high-tech vehicles, not to mention cellular phones and other personal communication devices that demand drivers' attention, the potential impediments to good driving performance may be increasing.

All drivers, no matter how experienced, are subject to natural limits of human behavior, cognition, and perception. But just as technology can help overcome physical limitations, it can also help address the perceptual and cognitive biases that often lead to less than optimal driving performance. The potential solution, says Manser, is using technologies that support—rather than impede—good driving practices.

Manser, who is interim director of the HumanFIRST Program, has been involved in a range of research projects focused on issues of driver performance since joining the University of Minnesota in 2002. For the past four years, he has been one of the primary researchers in a collaborative effort with Nissan Motor Company of Japan aimed at evaluating a new driver-assistive system that helps improve driver perception of lead vehicle status changes.

The Nissan system uses a haptic (touch-based) feedback mechanism attached to the accelerator pedal to provide variable resistance depending on how close the driver's vehicle is to a lead vehicle. The closer the vehicle gets to the lead vehicle, the more the pedal pushes back against the driver's foot. Forward-looking range sensors are able to sense changes in distance much more accurately and quickly than the human eye, and relay these changes instantly even if the driver's attention is elsewhere.

Although humans are endowed with highly evolved senses of hearing and touch, we rely almost exclusively on vision when we get behind the wheel. In this context, says Manser, haptic feedback systems are interesting because they exploit a relatively underused information channel that may not compete with the many visual cues that drivers already have to process. ITS Institute researchers have experimented with a number of other haptic feedback applications in the past, including the use of variable steering wheel resistance to signal bus operators that they are departing from a designated bus lane.

In order to understand how drivers use the haptic feedback system, and to determine if the system gave rise to any unintended consequences that could reduce driver safety, the HumanFIRST team carried out a series of tests in their state-of-the-art driving simulator and on a closed test track.

A number of in-vehicle technologies have been developed to address drivers' perceptual and physical limitations. One example is electronic stability control, which improves vehicle controllability by allowing an onboard computer to control the braking of individual wheels and, in some cases, adjust engine power during sudden maneuvers. Because these systems make driving physically and cognitively easier, Manser says, they all have the potential to improve driver performance by freeing the driver's resources to focus on primary driving tasks. However, technologies can have unintended consequences when they are used in ways their designers never intended. For example, instead of concentrating on driving, people may choose to use their extra cognitive resources to fine-tune the stereo system or chat on their cellular phones.

Haptic feedback is one example of how technology can be used to support and enhance the abilities of drivers. As researchers and automotive manufacturers continue to work together to develop new driver support systems, the future may see further improvements in driving performance.

"Today, we are beginning to develop technologies that address human performance limitations in completely new ways. These tools have the potential to improve performance and make driving easier and more comfortable—but, we need to understand first and foremost how human beings interact with new technologies."

 

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:

• Synthesis of Information Related to Transit Problems (TCRP Research Results Digest 86)

Journal of Public Transportation

The Journal of Public Transportation, Vol. 10, No. 4, 2007, published by the National Center for Transit Research at the University of South Florida, includes these articles, available at www.nctr.usf.edu/jpt/journalfulltext.htm:

• Transportation Management Associations: A Reappraisal
• Diagnostic Evaluation of Public Transportation Mode Choice in Addis Ababa
• Measuring the Impacts of Employer-based Transportation Demand Management Programs on an Interstate Corridor
• Documented Impact of Transportation Demand Management Programs Through the Case Study Method
• User Perceptions of Private Paratransit Operation in Indonesia
• Casual Carpooling—Enhanced
• Guaranteed Ride Home Programs: A Study of Program Characteristics, Utilization, and Cost
• Examining Incentives and Preferential Treatment of Carpools on Managed Lane Facilities
• Employer Perceptions and Implementation of Commute Alternatives Strategies

Transportation Infrastructure

Prestressed concrete beam standards examined

As federal standards for concrete bridge construction continue to evolve, questions are inevitably raised about the adequacy of older specifications. University of Minnesota researchers looked at prestessed concrete girders constructed according to an earlier specification for shear strength in order to see how they measured up to current estimates of required strength, and to develop a method for identifying girders that may be under-designed.

Civil engineering professors Catherine French and Carol Shield worked with graduate student Brian Runzell on the project, which received support from the Minnesota Department of Transportation.

The researchers evaluated several different shear strength specifications, including the American Association of State Highway and Transportation Officials (AASHTO) 1979 Interim specifications that were in force when the bridge was constructed, as well as the AASHTO 2002 Standard and 2004 LFRD Guidelines, in order to understand how specifications have changed over time. Each of these standards contains different provisions for calculating the shear capacity of prestressed concrete girders. 

Two sections of a girder from a bridge that had previously been removed from service were brought into the University’s Structures Laboratory for instrumented load testing to determine their shear capacity. One specimen was tested without a bridge deck, and the second with a deck that had been reconstructed following the removal of the original deck for transport. These experiments allowed the researchers to analyze the effects of the bridge deck on the girder’s shear strength.

The data gathered during the laboratory testing were analyzed to determine the effects of a variety of material parameters on shear strength, as well as the combined effect of all measured parameters. The tests indicated that the bridge girder from which the specimens were taken was sufficiently strong to bear the required loads.

Following the laboratory tests, a parametric study was carried out to determine if similar bridge girders with different characteristics were likely to have sufficient shear strength. This study identified certain design characteristics that are likely to be associated with underdesigned bridge girders warranting further investigation.

Mn/DOT has sponsored a companion research project titled “Discrepancies in Shear
Strength of Prestresssed Beams with Different Specifications”that includes a study of the effect of concrete arching action near the support and concrete strength gain with time on the shear capacity of existing bridge girders.

Shear Capacity of Prestressed Concrete Beams (Mn/DOT 2007-47) is available from the CTS Web site.

Transportation and the Environment

Stormwater research to influence state, national standards

Findings from University research into the effectiveness of stormwater management devices are influencing state and national standards. The research is led by Omid Mohseni, associate director of applied research at the St. Anthony Falls Laboratory (SAFL) on the Minneapolis campus.

Various levels of government spend millions of dollars on stormwater treatment, Mohseni said at a recent seminar sponsored by CTS, but guidelines to evaluate the effectiveness of the many proprietary devices on the market have been lacking. Third-party lab testing has been limited, and the results of monitoring in previous studies varied widely—up to 500 percent for some devices. The Minnesota research should contribute to better understanding of how to use small stormwater management devices effectively.

In 2005, SAFL received funding from the Minnesota Local Road Research Board and the Twin Cities Metropolitan Council to conduct field tests on four underground stormwater treatment devices in the metro area. In these tests, the researchers fed several sediment gradations (sizes) into the system at predefined concentrations and flow rates over a specified period of time. The sediment collected in the systems was then filtered, dried, and weighed to determine the true removal efficiency of each structure.

Mohseni and co-investigator John Gulliver, professor and former civil engineering department head, developed a new assessment procedure during their research. A city, for example, could set a target of removing 75 percent of specific particles, then use the procedure to choose the appropriate device, model, and size. The new procedure was incorporated into the Minnesota Stormwater Best Management Practices (BMP) Performance Assessment Protocol through funding from the Minnesota Pollution Control Agency.

Mohseni, Gulliver, civil engineering associate professor Raymond Holzalski, and graduate student Matthew Wilson recently completed a final research report on the project, detailing their research methodology and findings.

“Manufacturers are happy with the research…and are promoting it across the country and to Canada to encourage adoption,” Mohseni said.

In a follow-up project funded by the LRRB and Mn/DOT, Mohseni and Gulliver are assessing how underground stormwater treatment devices perform under high flow conditions such as severe storms. The results will also be integrated into the Stormwater BMP Assessment Protocol.

The research has received national recognition. Mohseni was invited to become a member of an American Society for Testing and Materials (ASTM) subcommittee that is developing a standard method for evaluating proprietary devices. “It is very likely that the method developed through this project becomes the standard method nationwide,” he said.

Also in 2007, Mohseni and Gulliver were assigned to chair the lab testing and scaling subcommittees, respectively, of the American Society of Civil Engineers (ASCE) Environmental and Water Resources Institute Task Committee on Guidelines for Certification of Manufactured Stormwater BMPs. The task committee is developing guidelines for evaluating proprietary underground devices.

In related news, a new stream restoration/ bioengineering facility is under construction at the St. Anthony Falls Laboratory called the Outdoor StreamLab (OSL). The facility evolved from an earlier Mn/DOT-funded project, Scoping Study for the Development of Design Guidelines for Bioengineering in the Upper Midwest. Funded by SAFL and the National Center for Earth-surface Dynamics (NCED), OSL will be used to investigate some of the fundamental processes and mechanisms involved in soil bioengineering techniques—which are widely used to protect slopes and river banks against erosion—as well as stream restoration and river morphology.

Performance Assessment of Underground Stormwater Treatment Devices (Mn/DOT 2007-46) is available from the CTS Web site.

 

Upcoming Events

February 14

12th Annual Minnesota Pavement Conference, St. Paul. Contact Shirley Mueffelman, 612-624-4754, cceconf2@umn.edu.

March 13

Annual Transportation Career Expo, Coffman Union, Minneapolis. For more information, contact Mindy Carlson at 612-625-1813, carlson@cts.umn.edu.

April 7

James L. Oberstar Forum on Transportation Policy and Technology. Contact Sara Van Essendelft, 612-624-3708, cceconf5@umn.edu.

May 20-21

19th Annual CTS Transportation Research Conference, St. Paul RiverCentre, Minnesota. Contact Sara Van Essendelft, 612-624-3708, cceconf5@umn.edu.