PHOENIX -- Police say more motorists trying to elude arrest for drunken driving are using social media sites like Twitter and Facebook to alert other drivers about DUI checkpoints.

Drivers with Smartphones are also shelling out money for a growing number of apps designed to warn of DUI patrols.

Officers said they don't mind the alerts, up to a point.

"We go out of our way to tell people when we're doing enforcement efforts," said Sgt. Tommy Thompson of the Phoenix Police Department.

But Thompson said law enforcement officials worry the extra distractions are putting other motorists at risk.

"Behind the wheel under the influence of alcohol and a young person doing it -- it's a recipe for diaster," Thompson said.

Police said the time it takes a motorist to tweet could be a major hazard.

"That brief fraction of a second that it takes to send a message, to hit a key or find a key, can be deadly," Thompson said.

Thompson said it's not a crime to put a warning out about checkpoints. But in Phoenix it's a secondary offense if motorists are caught texting and driving.