Michigan State Police have been employing a new tactic to catch people using their phones while driving.

Speaking on the Michigan Department of Transportation podcast, Talking Michigan Transportation, MSP Sergeant Bradley Campbell said Operation Ghost Rider has been deployed in southeast Michigan, using unmarked spotter vehicles to watch out for people playing with their phones. If a trooper in an unmarked vehicle sees a driver violating the state’s hands-free law, a trooper in a marked vehicle is radioed.

Campbell said there’s one big factor behind many hands-free violations.

“I asked one of the troopers out there that was out there yesterday, and I asked him, ‘When you have contact with these drivers using their phones while they’re driving, what is their excuse?’ And he came back he said, ‘Well, four out of nine traffic stops that I’ve had with them using a cell phone today alone, four were ignorant of the law itself.’”

Campbell said others were from out of state, so they could be given a break.

Under the state’s hands-free law, a driver may not hold their cell phone while in traffic.

Campbell said despite the extensive media coverage, it will still take some time for many drivers to become aware of the hands-free rule.