FRESNO, Calif. — In a ritual nearly as familiar as Santa Claus and crowded stores, police agencies again have stepped up enforcement of drunken-driving laws this holiday season, setting up sobriety checkpoints that studies show reduce alcohol-related crashes because drivers who've been drinking stay off the road, fearing arrest.
But some public-safety officials say those efforts are now being thwarted by technology, with drivers now using text messaging, Twitter and other tools to keep each other informed about the location of sobriety checkpoints.
There's eveb an iPhone application specifically designed to identify checkpoints, according to Sgt. Dave Gibeault, head of the Fresno Police Department's traffic unit.
Gibeault says his own daughter often sends him text messages about where she's heard he's running checkpoints.
On Twitter, a free electronic message service that runs on both cell phones and computers, drivers can warn each other with "tweets" listing intersections where police have set up checkpoints.
Fresno attorney Brian Andritch sees nothing wrong with efforts to spread the word about checkpoints.
Andritch, who used to prosecute drunken drivers when he worked in the Fresno County District Attorney's Office, now defends them -- and warns others about sobriety checkpoints on Twitter.
"I don't see how it's any different from what police are doing in promoting checkpoints," he said in an interview.
Gibeault said it's one thing to spread the word about checkpoints in general, which police want. It's quite another to provide information that might encourage people to drive drunk, he said.
Wayne Ziese, a spokesman for the California Office of Traffic Safety, said he's heard a lot of stories about young people using technology to avoid drunken driving arrests.
"Young people continue to be the most dangerous drivers," he said. "They will continue to drink and drive until they have families and realize they have something to lose."
Ziese said law enforcement hasn't figured out how to respond to the more immediate and precise information about checkpoints circulating on the Web and via cell phones. The Office of Traffic Safety provides funding to help with such enforcement, including more than $5 million to Fresno County agencies in the last five years.
"New technology brings us new challenges, whether it's warfare or DUI," Ziese said.
Fresno police are known for their innovative approaches to DUI enforcement, and will likely figure out an appropriate response, Ziese said.
But changing the checkpoints can be a problem, Gibeault said. Police can't easily move them once their location has been broadcast, because of legal requirements and the large number of officers and equipment involved, he said.
In any case, the purpose of the checkpoints isn't to take drunken drivers off the road, Gibeault said. The point is preventing them from getting in the car in the first place. In 2001, experts convened by the Centers for Disease Control and Prevention reached the same conclusion. The group concluded that checkpoints reduced alcohol-related accidents by an average of 20%.
"Although checkpoints may remove some drinking drivers from the road, their primary goal is to reduce driving after drinking by increasing the perceived risk of arrest," the researchers said.
Saturation patrols -- in which police focus on troubled areas with a lot of officers on the move -- are more effective than checkpoints at catching drunken drivers, Gibeault said.
In the last three winter holiday seasons, more than 18,000 vehicles have passed through checkpoints in Fresno and Madera counties, according to the Office of Traffic Safety. Only 1% of the motorists were arrested for driving under the influence.
By contrast, saturation patrols conducted during the same time produced seven times as many arrests for driving under the influence. Valley's young drivers use technology to avoid DUI checkpoints
"I was a hard sell on checkpoints," Gibeault concedes. "I wanted to put drunk drivers in jail."
But he said he learned over time how effective checkpoints are.
He said he remains a strong supporter of checkpoints, even though the number of drunken-driving accidents has gone up during winter holidays in Fresno.
Last winter holiday, motorists charged with driving under the influence were involved in 49 crashes, compared to 36 five years earlier, police figures show.
Some of the increase is likely due to population gains, and the jump would have been higher if not for checkpoints, Gibeault said.
Clovis Police Chief Janet Davis said more people would have been hurt or killed if checkpoints weren't set up, and police must continue the effort.
"We're still doing these campaigns because people aren't getting it," she said.