An American driver is facing a $48,000 fine after using a mobile signal jammer in his car to block motorists around him from using their phones on the road.

Jason Humphreys reportedly used the jammer from the back seat of his Toyota Highlander for around two years before being caught by Florida police.

The 60-year-old said that he used the jammer – which transmits radio signals that interfere with mobile phones – because he was ‘fed up’ with watching others use their phones on the road.

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Although it’s not illegal to make a phone call while driving in Florida, motorists are only allowed to text when stationary.

Police cottoned on to Humphrey’s vigilantism after a mobile phone operators (Metro PCS) reported interference to their phone towers’ signal during commuting hours.

Agents from the Federal Communications Commission tracked down the blocking signals to Humphrey’s SUV, with their report stating that as they pulled the car over they lost contact on their police radios.

“He indicated on the day that we stopped him that he was pretty much fed up with watching cell phone usage while people were driving,” Larry McKinnon, a spokesperson for Hillsborough County Sheriff's Office told ABC Action News.

Unfortunately for Humphreys, mobile phone jammers are banned in the US because they can interfere with devices used by ambulances and other emergency responders.

“The moral issue is that it's just very dangerous,” said McKinnon.

Humphreys now has 30 days to pay the $48,000 fine or file a written response with the FCC.