Drivers with unpaid Ohio River bridge tolls could soon face a new penalty: a frozen vehicle registration.

Officials say about 16,000 Kentucky drivers and "slightly more" Hoosiers will have holds placed on their accounts under an enforcement mechanism for toll collection expected to go into effect this month. The frozen registrations will prevent drivers from renewing their registration until the fine or charge has been paid.

Tolling began Dec. 30 on three Ohio River bridges connecting Louisville and Southern Indiana – the Lewis and Clark Bridge (or the East End bridge), the Abraham Lincoln Bridge and the Kennedy bridge.

Related:Ohio River bridges doing 'what they were supposed to do' as number of crossings rise

Answers:How will bridge tolls work? And how do I pay?

Since then, the toll system has collected about $50.2 million, according to a presentation this week from Megan McLain, Kentucky Transportation Cabinet's innovative finance manager, before the legislature's interim joint committee on transportation. The average daily traffic for September was 80,533 vehicles, she said.

Motorists who face frozen registration will have received two invoices, a violation notice and a collection notice before their registration is frozen, McLain said.

►The first invoice is just for the toll amount and gives drivers 30 days to pay.

►The second invoice is the toll amount plus a $5 fee, to be paid in 20 days.

►The violation notice adds a $25 fine to the toll and $5 fee and gives drivers 30 days to pay.

►The collection notice, which is due on receipt, is the toll amount, plus the $5 fee, plus the $25 fine, plus an additional $30 fee. The registration hold is placed 10 days after that collections notice is mailed.

"It's not that you get one bill, don't pay, and we put a hold on your vehicle registration," McLain said. "There are four notices that are provided, it's over a period of 100 days that you haven't paid your toll before a hold would be placed on your vehicle registration," McLain said.

Read this:One of Louisville's only toll-free bridges could close to traffic again

RiverLink is all-electronic tolling, with no stopping, no slowing, no lines and no coin machines. Drivers pay through transponders, which correspond to prepaid accounts, or through invoices, after cameras capture their license plates and bills are sent to the vehicle's registered owner.

Drivers with transponders pay the lowest toll rates, at a difference of $2 per crossing.

On weekdays, roughly 60 to 65 percent of drivers have transponders and, on weekends, that number dips to 45 to 50 percent. Those figures are "right on target," McLain said.

The Clark Memorial Bridge at the end of Second Street in Louisville and the Sherman Minton Bridge, which connects western Louisville and New Albany, Indiana, remain free to crossing vehicles. The Sherman Minton, though, may close to traffic in a few years when it undergoes an estimated $80 million paint job and repairs.

Reach reporter Darcy Costello at dcostello@courier-journal.com or 502-582-4834.