For many people, getting away for a holiday means sitting in traffic while listening to radio reports about rubbernecking delays and cascading backups.
But during the next few days, as Americans extend their Fourth of July celebrations, tens of thousands of motorists around the country will receive up-to-the minute accident alerts and guidance on end runs around bottlenecks -- without having to turn on a car radio.
In the latest incarnation of traffic reporting, information gleaned from cameras, road-top sensors, electronic tollbooths and eyewitnesses is edited in Mission Control-style command rooms and sent out via personalized text or voice messages to subscribers' cell phones or BlackBerrys, often at no charge.
These advances are part of an attempt by private traffic services to bring some science and precision to what, at least until the past few years, was an art form typically practiced by a reporter in a helicopter or an announcer glued to a terminal. While radio stations continue to send traffic choppers into the air, their observations are now only one of the streams of data at travelers' disposal.
The new traffic reports are still largely produced by AM and FM radio stations or their partners, even though the reports might give motorists one less reason to tune in the very station supplying the new alerts, such as WINS in New York or WTOP in Washington.
"Radio was always about coming out of the dashboard of the car or the clock radio when your alarm goes off," said Mark Mason, executive editor of WINS, an all-news station that, like print and TV news outlets, is facing more competition than ever, including from iPods and satellite radio. "While we have to continue to be in our users' ears, we also need to be in the palms of their hands -- where they are, whenever they are."
David Cary, a commercial real estate appraiser who drives 500 miles a week in and around Boston, said he was increasingly tuning out a local radio station's "Traffic on the 3s" report in favor of SmarTraveler, a personalized service offered by a unit of Westwood One, a radio syndicator and a major traffic-watching provider. To find out if the coast is clear, he can hit (AST)1 on his cell phone and then choose from a menu of recorded updates on major roads.
"It told me it was OK to head for the Cape," Cary said by phone from his Volvo station wagon as he knocked off work for the weekend. "That the bridges weren't backed up."
Bill Lowry, senior director of security for Dolphin Stadium in Miami, where the Miami Dolphins play, said he was so impressed with a similar service that he uses to navigate from his home in Fort Lauderdale that he is working with Westwood One to develop a game-day service for fans.
Believed to be the first of its kind in the NFL, the service will send alerts to people as they approach the stadium telling them of accidents, slowdowns and parking availability.
Westwood One, which said more than 100,000 people across the country have signed up for personalized alerts in the past year or so, hardly has the field to itself.
Traffic.com provides customized bulletins to motorists in more than four dozen cities and estimates its subscriber list at 500,000. It is owned by Navteq, an industry leader in drafting digital maps, including those used in auto-navigation systems.
Clear Channel, the radio behemoth, has spurned outside traffic providers such as Westwood One in recent years and has developed its own reporting service, which is reached through realtimetraffic.net.