Charges at the Dartford tunnel and bridge will increase significantly during the day, but be scrapped at night, while a study looking at building a new crossing will also be launched.
The Department for Transport wants to increase cash charges for cars by 50%, from £1 to £1.50 for each crossing, and the pre-paid DART-Tag card increases from 93p to £1.
All traffic would be able to use the bridge and tunnel for free between 10pm and 6am under the new plan, however.
Transport minister Stephen Ladyman said: 'In the longer term, pressure at the crossing will continue to get worse.
'I have therefore requested a study of how we can best address this, including the possibility of a new crossing.'
A consultation on the increased charges will begin in December, with the goal of having the new charges in place by January 2008.
The Government's original plan was to scrap all charges for the Dartford crossing once the Queen Elizabeth II bridge, completed in 1991 and used for southbound traffic, was paid for.
This came in 2003, but charges have continued and generated more than £100 million in revenue.
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