Sensors will help drivers plot a course

Updates on signs, Web, phones and PDAs will help drivers skirt jams, wrecks

The traffic jams won't go away, but a planned digital network of roadside sensors will give Triangle commuters more chances to steer clear of trouble on the region's most congested roads.

The state Board of Transportation is expected Thursday to approve a federally funded $2 million plan to generate real-time information about traffic speeds, congestion and travel times on 80 miles of local interstates and major highways.

Solar-powered microwave sensors will scan traffic continuously and transmit frequent updates over a wireless Internet link. The full system could be operating by summer 2008. It will add high-tech muscle to a fledgling state effort to help Triangle travelers keep up with road conditions.

Even when motorists find out about wrecks and construction delays too late to avoid them, they'll get a better idea of how long they can expect to be stuck in traffic.

"There's not a lot else we can offer at that point," said Kelly E. Damron, who oversees travel technology operations for the state Department of Transportation. "We just want to give people the information to make the best decisions they can."

"Sometimes you decide to just cancel your trip. Maybe you're going to get there 40 minutes late, and the meeting will be over by the time you get there," Damron said.

"Or you call someone and say, 'Honey, I left work at 5 o'clock, and there's a mess out here on I-40. I'm not going to be home at 5:45. I'm going to be home at 6:15.'"

The DOT's local traffic management center in West Raleigh now posts travel-time estimates during the afternoon rush on four electronic signs overhead -- one on westbound Interstate 40, and three for eastbound drivers. The messages are a test of how well DOT can do with a few employees and a string of low-cost radar sensors that were installed on I-40 in 2005.

DOT engineer Archie Wells oversees the drivers who patrol I-40 to help stranded motorists and speed the removal of wrecked vehicles. On a recent weekday afternoon he scanned a bank of traffic camera monitors, checked a DOT web page that shows what speeds the I-40 sensors are reporting, and typed out estimated travel times, which were instantly posted on those four overhead signs.

Wells worried that he might mislead commuters about how fast the traffic ahead was moving. A sensor at Harrison Avenue was out of commission, and another at Miami Boulevard fluctuated erratically.

"I don't have much faith in this particular one at Miami," said Wells, 57, a 29-year DOT veteran. It said 35 mph, but on a video monitor the traffic looked faster.

Traffic on your PDA

The new sensor network will be installed and operated by Traffic.com, which distributes real-time traffic information to urban drivers across the country, under a $2 million contract with the Federal Highway Administration.

Motorists will get updates about road speeds, congestion levels and travel times on DOT and local news media Web sites, through the DOT's 511 telephone service, and on a few electronic highway signs. Traffic.com will distribute the information to its customers' telephones and personal digital gadgets, and on its Web site.

"If you clicked on Raleigh, you'd see how sketchy our data is right now," said John J. Collins, a vice president of Traffic.com, based in suburban Philadelphia. "This is really going to be a quantum step forward for travelers in the Raleigh area."

Some commuters find reassurance in the flashing travel-time messages. When a sign near Aviation Parkway says the Durham Freeway is five to seven minutes ahead, that's a welcome sign that afternoon traffic on the Triangle's busiest highway is flowing freely, about a mile a minute.

"As long as I see that '5 to 7 minutes,' it doesn't look like there's any trouble ahead," said Odis B. Newsome of Durham, who takes I-40 and the Durham Freeway home from work at N.C. State University in Raleigh. "If that changed, I would probably try to get off at an exit earlier."

The DOT picked up the sensors it uses on I-40 with money left over from another technology project that came in under budget. Less sophisticated than Traffic.com's microwave devices, they are supposed to calculate an average speed for all three or four lanes of traffic.

"Us guys who have been around awhile feel like we're taking a little bit of a risk, putting these travel times out there," Wells said. "We've been doing it as an experimental thing until we get better data and a more reliable system."

He shared his concerns when one of his DOT supervisors called in at 5:30 p.m. Brandon Jones, DOT operations engineer for Wake and six other counties, checked his travel time on his way home and told Wells that the estimate flashing on an eastbound I-40 sign was right on the money.

Wells was relieved. "People like it if you can keep it accurate," Wells said. " ... If something that should take you 10 minutes is going to take 30, you want to know."