Clearing Congestion

Imagine starting your car's ignition and hitting the road at the height of rush hour, confident you'll avoid traffic snarls or fender benders along the way. Although this may seem like a commuter's fantasy, transportation experts say this may one day become a reality.

Next-generation intelligent transportation systems (ITS) are starting to creep onto the nation's roadways and into vehicles as federal, state and local agencies look for new ways to reduce congestion, improve driver safety and lower fuel emissions. transportation agencies have long been adding intelligence into their infrastructures, but these latest systems top off the traditional sensor and surveillance gear with advanced communications technology and sophisticated electronics that gather and disseminate motorist advisories or make system decisions in real time. Such innovative and far-reaching ITS programs are already under way in Texas, California, Michigan and Georgia.

Texas Teamwork

In San Antonio, the Texas Department of Transportation (TxDOT) uses cameras, dynamic message boards, lane-control signals and speed warning devices to manage the flow of expressway traffic. Likewise, on arterial roads, the city traffic management department optimizes traffic flow through signal management systems while the transit system uses a global positioning system–automated vehicle-location system to provide bus schedule information in real time and improve performance on its routes. now, the three agencies are teaming to build an integrated corridor management (ICM) system that takes into account what's happening on all three transportation networks.

If traffic gets clogged on the main highway, for example, city traffic coordinators could modify signal timing on arterial roadways to make sure they can handle traffic diverted from the highway, keeping buses on schedule, says Brian Fariello, TxDOT traffic management engineer. The traffic signal plans would be predetermined in collaboration with other ICM stakeholders and fed into a decision support system (DSS) that traffic managers would use to determine how to modify their infrastructures, adds Lilly Banda, San Antonio's traffic management engineer.

For the city, the traffic signals themselves would relay timing information to each other over a high-speed wireless network. "This gives us the backbone we need to work with TxDOT," Banda says.

The San Antonio program is one of eight pioneer ICM projects funded in part by the U.S. Department of Transportation's Research and Innovative Technology Administration (RITA). "We need full visibility into what's going on in a network," says Shelley Row, director of RITA's ITS joint program office. "A multimodal vision is key to better performance of service transportation."

Fog Patrol

In California's Central Valley, the state transportation department is rolling out a fog-warning system on one notoriously dangerous 12-mile stretch along state route 99, site of an 86-car pile-up in November 2007. Now this piece of highway is monitored by a sophisticated ITS comprising 41 microwave motion detectors, 22 visibility sensors and six weather stations, says anthony Lopez, a traffic supervisor with the California Department of Transportation. This summer, Caltrans will add a dozen closed-circuit tVs (CCTVs) into the mix.

Data, such as vehicular speed, rate of acceleration or deceleration and moisture in the air, is fed into a central transportation management system over an advanced wireless network. The Caltrans system uses Proxim Wireless' Tsunami MP.11 5054 base stations and 5012 subscriber units, which transmit the data using WiMmax technology. Within 30 seconds of receiving the roadside data, the transportation management system will send alerts to a network of 33 permanent and six portable electronic message signs along the route, Lopez says.

WiMax availability helped Caltrans quickly meet a commitment it made to address the Central Valley fog-crash problem, Lopez says. "This provides us an innovative way to advise motorists of situations that are happening downstream so they make a decision to slow down or stop or to take an alternative route."

Simply put, the goal is to keep fast-moving cars just arriving at foggy patches from slamming into visibly obscured, slow-moving vehicles.

Smart Cars

Avoiding crashes is the goal of an ITS project in Michigan, too. The Michigan Department of Transportation (MDOT) is one of several state agencies that has partnered with the auto industry to get vehicles "talking" to one another, to infrastructure components or to handheld devices such as cell phones and personal digital assistants over high-speed wireless networks, says Greg Krueger, who is ITS program manager for MDOT as well as chair of a national task force studying this type of ITS technology, called IntelliDrive.

The idea behind IntelliDrive has been around for years, but technology has only now caught up to it, Krueger says. IEEE 802.11-based wireless networking, for example, affords MDOT and others the ability to build open, high-speed wireless platforms to support short-range vehicle communications in the Federal Communications Commission–allotted 5.9gHz spectrum.

"Think about a vehicle providing a heartbeat, broadcasting every hundredth of a second, saying ‘Here I am, and here's what I'm doing. I'm at a GPS location, traveling with this velocity in this direction, applying this amount of pressure to the brake or accelerator.' Other vehicles on the road also are broadcasting, with everything going into one big radio cloud, and any devices in range can receive a broadcast of the heartbeat," Krueger describes.

Using that information, developers could create all sorts of safety and mobility applications, Krueger says. "Twenty years from now, a car should be able to stop itself, but today, that directive might come to drivers through sensors like radio beeps or dashboard lights," he adds.

Vehicle-to-vehicle and vehicle-to-infrastructure communications will enable all sorts of interesting safety and mobile applications, agrees Sathyanarayana Kabibas, a senior research analyst at Frost & Sullivan. "But I'm not 100 percent sure when," he adds, noting overriding factors such as cost, interoperability, the volume of cars with built-in GPS and current market conditions.

NaviGAtor Network

While wireless communication is enhancing many state ITS projects, fiber-optic networks still serve their purpose for the Georgia Department of Transportation's highway system in and around Atlanta, says Hugh Colton, operations manager for the GDOT transportation management Center (TMC).

GDOT operates a massive ITS, known as NaviGAtor. It comprises 487 CCTVs, 1,645 video cameras and 548 video processing units, 86 radar units and ramp meters to control traffic moving on freeways during rush hours, Colton says. Data from these devices travel across a Nortel-based gigabit ethernet network, which includes 25 hubs and multiple redundant routes into the TMC, Colton says.

At the TMC, GDOT funnels data into a database and shows visuals on a network operations center–like display wall. Travelers can view the same images at www.georgianavigator.com. From the TMC, traffic alerts traverse back over the network for display on more than 100 dynamic message signs in the Atlanta metro area alone, he adds.

GDOT has been building its ITS for more than a decade, beginning with development of the advanced transportation infrastructure in support of the 1996 Olympics in Atlanta. The ITS now provides incident management, traveler alerts, emergency dispatch services and the like for more than 196 miles of roadway, with another 25 miles set for completion by year's end, Colton says.

That doesn't leave much urban roadway left to conquer, so next up for Colton is figuring out the feasibility of using cell phones as probes to provide speed data in rural areas. He's experimenting with using a 3G phone system: "It's a viable future."