SCOTLAND'S first motorway bus lane will go live next month in a bid to ease congestion on the M90 approach to the Forth Road Bridge in Fife.

An intelligent transport system (ITS), including variable traffic speeds, will be in place during construction of the £1.6 billion crossing over the next four years and will then become a permanent fixture between the Halbeath junction north of the bridge to the M9 Newbridge Junction in the south.

Such "managed motorways" are in place on a number of routes in England and have been credited with improving traffic flows during busy periods.

The system features gantries linked to traffic sensors in the road. These detect when con-gestion is likely and vary speed limits to keep traffic moving.

Transport Minister Keith Brown said ITS was an "early benefit" from the project.