A new congestion-busting carpool lane for the M25 is being considered by the Government.
Transport Secretary Alastair Darling has asked the Highways Agency to look at whether such a lane could be installed to encourage drivers to share cars and help the environment.
The M25 circles London and is one of the UK's busiest motorways.
The section under consideration is already being widened to provide either five or six lanes in each direction and the carpool lane could help make the best possible use of this additional capacity.
A trial motorway car pool lane is already planned for the M1 between St Albans to Luton. Such lanes are already a big success in the United States.
Mr. Darling said:
"I am determined to make the best possible use of the road network. Carpool lanes have an important role to play in making best use of road space, as well as helping the environment and reducing congestion."
The Highways Agency will now undertake further consultation and detailed investigation and design work before any final decisions are made.