Traffic lights on the M25?
The lights would stop vehicles from joining the motorway for up to a minute, allowing traffic already on the motorway to flow.
However, there are concerns that stopping traffic from joining the motorway could lead to delays on access routes. Road engineers in counties bordering the M25 also fear it could provoke gridlock on country roads if congestion on the motorway gets too high.
Talks have started between the Highways Agency and local authorities, although no date has been set to trial the traffic lights.