Tolls on the Dartford Crossing could soon be waived during bouts of severe congestion on the M25.
The Government has said it is prepared to look at the idea to help improve traffic flow on the busy toll crossing.
A Highways Agency study will also look at the feasibility of a licence-plate charging system, which could replace the current barrier system and so reduce congestion.
Roads minister Mike Penning said: 'Reducing congestion at the Dartford Crossing is an absolute priority.
'Our preferred option is the use of newer technology to allow free-flow charging, and we have asked the Highways Agency to work on proposals as a matter of urgency.'
'However, we are also willing to consider the possibility of lifting the barriers when congestion is particularly severe.'
Free for all
Protest groups have called for the tolls to be abolished, and that the crossing should have been free to use after 2003 the year that all building costs were recouped.
Charges have already been axed on all bridges in Scotland, with the final toll-paying crossings the Forth Bridge and Tay Bridge having their levy removed in 2008.
The Dartford Tunnel and Queen Elizabeth II bridge are the most easterly crossing point on the river Thames and link the north and south sections of the M25. About 150,000 vehicles use the crossings each day.
However, the tolls have been blamed for causing a bottleneck that regularly hampers transport in the area. The AA said in November 2009 that delays on the M25 had increased markedly in November 2008 when the toll charge was increased from 1 to 1.50 for cars.