SALT LAKE CITY -- One in every five people driving on the I-15 express lane is actually breaking the law, and the Utah Department of Transportation said those drivers are costing the state a lot of money.

UDOT officials said these people are either driving in the lane by themselves or that they aren't paying the tolls in the lane with their electronic pass.

The passes cost the state $2.85 a month, but many people want to avoid being charged --so they don't turn them on.

"If you're not utilizing the system, we're still paying that $2.85 a month for every transponder,” said Jason Davis of UDOT. “So over, almost half of the users don't even use their transponder for months at a time, some have never used the transponder.”

Those costs amount to about $19,000 each month, Davis said. He added that in addition to incurring monetary losses, the drivers are also slowing down traffic by adding cars to a lane that shouldn't be there.