Motorists have been hit with £4.8m in fines since changes were introduced in paying to use the Dartford Crossing.
A Freedom of Information request has revealed that £4,837,013.39 of penalty charges were paid between November 2014 and August this year.
The Department for Transport added: “By law, all revenues from the Dartford Crossing are invested in transport improvements.
“The relevant legislation is Schedule 12 of the Transport Act 2000, where there is a requirement that any net proceeds be available only for application for the purposes of directly or indirectly facilitating the achievement of any policies or proposals relating to transport.”
The Dart Charge was introduced last November and meant drivers could no longer pay at toll booths.
Crossing users must now pay in advance or by midnight on the day the use the bridge or tunnel under a similar system to the London Congestion Charge.