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Institute of Transportation Engineers

Strategies for Addressing Congestion
By John N. LaPlante, P.E., PTOE

Strategies for addressing congestion are at the heart of traditional traffic engineering. This track at the ITE 2007 Technical Conference and Exhibit in San Diego, CA, USA, was well attended at every session and provided many good ideas. Following is a brief synopsis of all eight sessions in this track and some of the highlights.

Measuring Congestion
The basic premise of this session was: “What gets measured gets managed.” Assuming that we want to be able to communicate our measurements and their meaning to our clients and the public, there were several admonitions against using techno-babble or acronyms when reporting measurements. Standard statistical terminology does not “communicate” and, despite our best efforts, very few people know what level of service really means.

Given our increasingly limited manpower resources, selecting which performance measures to use can be very important. On the other hand, we cannot be too parsimonious in presenting our data, because we need some very good supporting data if we ever want to expand or even retain our current programs. One of the recommended performance measures was “reliability”—consistently knowing how long it will take to make a familiar journey is something that everyone can relate to.

The session ended with a description of a current ITE project to develop a review of public agency performance measurement practices. Public agencies willing to participate in this survey are invited to visit the ITE Web site at www.ite.org/councils/pac/performancemeasurement.asp.

Future Signal Systems: Improving Safety and Congestion
Vehicle infrastructure integration (VII) and cooperative intersection collision avoidance systems (CICAS) were the subject of one whole session plus a live demonstration in the hotel parking lot. The VII movement has been dubbed “Internet on wheels.” The goal is to equip vehicles so they can communicate with each other and the roadway in real time.

The Federal Highway Administration (FHWA) is establishing a number of test-based sites to prove technical viability prior to any nationwide implementation. Two projects discussed in this session were a system providing real-time feedback on signal operations in Oakland County, MI, USA and the California Department of Transportation’s (Caltrans) installation of responsive ramp metering on some Bay area freeways and work with private companies to create an area-wide test bed system at 40 signalized intersections in Palo Alto, CA, USA.

This advanced intelligent transportation systems (ITS) effort seeks to eventually provide interaction among traffic management, emergency response, traveler information and vehicle control systems. Practical applications could include decreasing emergency response time; reducing red-light running and STOP-sign running; preventing sharp curve run-off-the-road crashes; providing timely warnings to preclude vehicle-vehicle crashes; and decreasing fuel consumption. More controversial applications would include automatic toll collection and congestion pricing options.

Integrating Transportation Safety and Congestion Management
This session discussed safety as it relates to congestion and included presentations on work zone crashes, shoulder travel lane experiences and the relationship between crash rates and congestion. Not surprisingly, freeway crashes increase with increased levels of congestion on the highway, with the lowest crash rates at level of service B. However, the nexus between crash rates and congestion is not nearly as pronounced on arterial streets, where the highest costs associated with crashes occurred on heavily-traveled roads during non-peak hours.

Work zone crashes still account for 1,000 fatalities each year. FHWA safety grants emphasize the development of guidelines for reducing work zone crashes and guideline training for state and local agency construction workers. A Virginia Department of Transportation study on managed lane use of shoulders for high-occupancy vehicle travel lanes found that shoulder travel lane use does not appear to affect crashes.

Arterial Management/Signal Timing Strategies
These two sessions were similar in content and presented some interesting and innovative applications and ideas. FHWA-funded signal system upgrades are underway in New York (countywide in Westchester and Rockland Counties) and Florida (a major arterial corridor in Ft. Walton Beach). The purpose of these linked studies is to determine to what extent signal timing and equipment upgrades alone can create progressive traffic flows that will reduce congestion and improve air quality.

There also was a report on the results of a congestion mitigation and air quality project in Garland, TX, USA, on the effectiveness of using an uneven double-cycle traffic signal operation along a major suburban arterial. This unique operation reduced delay in the face of significant traffic volume increases and, despite using an overall cycle length of 160 seconds, reduced maximum wait times on most cross streets with the judicious insertion of shorter cycles of uneven lengths at certain locations.

There were three presentations on using advance detection to reduce dilemma zone uncertainties for large trucks approaching signalized intersections on high-speed roadways, including status reports on current studies in Lubbock, TX and Portland, OR, USA. In both cases, this resulted in reduced red-light running (a 50-percent decrease in Portland) and unnecessary truck stopping.

An interesting side light of the Portland test site was the ability to recoup $537,000 in installation costs for dilemma zone detection by selling carbon credits from the improved traffic operations to an environmental improvement firm, Climate trust. Contact Portland Signals and Street Lighting Manager William C. Kloos for further details on this truly imaginative funding alternative.

Arlington, VA, USA, is pursuing a program on managing its arterial streets based largely on complete streets principles. We know how residential streets can be “calmed”; now we are learning that arterial streets can be “tamed.” Part of the success of this program involved moving away from functional classifications and toward street typologies, recognizing that the street must serve the adjacent land uses if the community is to survive. This leads to more emphasis on pedestrian, bicycle and transit movement needs and having traffic move slowly and steadily instead of fast and choppy.

Traveler Information
This session featured an interesting presentation from Israel on how cell phones are being used in that country to anonymously collect road traffic and travel time information. As cell phone usage increases exponentially, this could be much more cost effective than installing roadway sensors in miles of roadways in urban areas. Further testing of this concept is now underway in two U.S. cities.

In Lexington, KY, USA, a local public information cable TV channel is being used by the traffic management center (TMC) to impart traffic condition and travel time information during the morning peak period. This service has a 68-percent awareness level, competing favorably with major network offerings in this same prime time slot.

In California, Caltrans is developing a multimodal 511 phone and Web-based travel information system. Connections can be made to a mobile callbox, car pool ride links and transit times and customer service options. The program is up and running in Los Angeles, CA and the Bay area and has just begun in San Diego.

Integrated Corridor Management
The City of Orange, CA, has created its own TMC with minimal outside assistance and a very limited budget. This presentation showed how other smaller cities can design and equip a TMC on a shoestring budget.

At the other end of the sophistication spectrum, FHWA is supporting the development of an integrated corridor management (ICM) program at eight pioneer sites throughout the United States. The intent of these programs is to integrate freeways, arterial street signals, rail transit and bus transit into one jointly-operated multimodal regional transportation management system. This program has four phases: foundational research and documentation; developing corridor tools, strategies and integration techniques; corridor site development and demonstration models at eight pioneer sites around the United States; and outreach to disseminate knowledge and technology transfer.

Oakland County, CA, is one of the eight pioneer sites. Its Interstate 880 ICM test project has identified three distinct challenges so far: technical, operational and institutional. It has found that the technical challenges are relatively easy to deal with and the operational challenges are definitely do-able. The institutional challenges, involving many disparate stakeholders, are the most difficult. Echoing the message of the very first session, having good data is the key to managing all three challenges.

Increasing Capacity: A Realistic Approach to Reducing Congestion?
The highlight of this track was the conversation circle discussion on increasing capacity to reduce congestion. This discussion was based on the reason foundation’s premise that congestion can be solved and added capacity is a major part of providing sustainable congestion relief. This sustainability is based on the further premise that value pricing will be built into any future added-capacity project.

This proposal was challenged and countered by the assertion that although the investment in infrastructure is not keeping pace with growth, building out of congestion by adding lanes is a fairytale. Can we build our way out of the one-car/one-person mindset? It was reported that to meet a certain new Jersey corridor demand need, an 80-lane freeway would be needed.

Alternative solutions to moving beyond congestion offered in this conversation circle included:

There was a final group consensus that doing nothing will not solve the problem. The answer involves a balanced use of all the proposed alternatives. This can include carefully targeted roadway capacity improvements and innovative congestion pricing techniques. This hearkened back to the remarks by assistant Secretary for Transportation Policy Tim Duvall at the opening session of the conference. Introducing congestion pricing now instead of later to help avoid some of the infrastructure costs implied above probably is not politically feasible now but will become more acceptable as congestion increases.

We are all familiar with the “Field of Dreams” quote: “Build it, and they will come.” The traffic corollary to that adage is: “Don’t build it and they will still come.” This means we have our work cut out for us. It will require all of us working together with a multiplicity of tools and approaches to eventually move beyond congestion.

John N. LaPlante, P.E., PTOE, is chief transportation planning engineer for T.Y. Lin International Inc., working out of the Chicago, IL, USA, office. Prior to joining the firm in 1992, he was with the City of Chicago for 30 years in various transportation engineering positions, including chief city traffic engineer, first deputy commissioner of public works and acting commissioner of the new department of transportation. His education includes a B.S.C.E. from the Illinois Institute of Technology and an M.S.C.E. from Northwestern University.