More than 150,000 foreign-registered lorries failed to pay the Dart Charge in the past year according to a Freedom of Information request by Kent Liberal Democrats, who are calling for a new system to be introduced as soon as possible.
The Liberal Democrat Group has also raised concerns that drivers may face a different charging system and costs for the Lower Thames Crossing - councillors say Highways England should ensure consistency.
This is just one of the issues surrounding the project - the much-needed improvements to critical link roads such as the A299, A249 and M2 have been ignored.
Highways England are consulting on their latest proposals for the Lower Thames Crossing. They are now planning two three-lane road tunnels to between Kent and Essex which will join the A2 just east of Gravesend. The work is due to be completed by 2027.
The earlier proposals included plans for major improvements to the A229 Bluebell Hill or the A249 Detling Hill, both of which are accident black spots and are frequently seriously congested. Essential improvements to these link roads between the M2 and the M20 have been removed from the latest plans.
These link roads are critical for traffic heading from the new crossing to and from the Channel Tunnel. Initially both were considered for improvement, but they have been removed from the plans due to financial constraints.
Likewise, there is no plan to improve the M2 east of Gillingham and the A2 from Brenley Corner, which will be the main route to Dover for vehicles using the new crossing. At present this route is only two lanes each way.
The collection of tolls from foreign vehicles has remained an unresolved problem on the Dartford Crossing since 2014 when the toll booths were removed.
County Councillor Ian Chittenden, Lib Dem Spokesperson on Transport issues on the County Council said:
"The decision not to improve the link roads serving the crossing - already accident black spots - risks worsening traffic problems in years to come. Exactly the opposite outcome we all want.
"The continued failure to collect tolls from foreign registered vehicles is getting ridiculous. A new system should be introduced as quickly as possible, and the new Lower Thames Crossing should have a consistent system when completed and open for use."
Further information about the Lower Thames Crossing and Highways England's consultation can be found here.
The consultation closes on 20th December 2018.