Close to 17 million vehicles are being driven on U.S. roads with expired tags, according to vehicle history provider CARFAX, with drivers risking fines, impoundment and jail time.

Expired tags can also complicate accident issues, potentially affecting insurance claims.

The average lag for most drivers with expired tags is four months, according to CARFAX data.

“As summer kicks off and more families hit the road, a simple missed renewal can quickly spiral into a costly legal or financial headache,” said Paul Nadjarian, general manager of CARFAX Car Care.

These 10 states had the most expired vehicle registrations at the start of the year:

Some states administer penalties of hundreds or even thousands of dollars for expired tags. In addition, drivers may face jail time for repeat offenses in the following states: New York, Florida, Washington and Georgia.

In California, the Department of Motor Vehicles (DMV) states that if a vehicle’s registration is expired for more than six months, law enforcement may order it towed or impounded. And although jail time isn’t typical, that decision “would be up to a judge”.

*Note: California’s figures are a recent monthly average of expired tags provided by the California Department of Motor Vehicles (DMV).