Transport Scotland has shortlisted four tenders from seven major construction firms for the upgrade of Junction 1a on the M9, a key element of the new Forth Replacement Crossing (FRC) scheme.

The competing companies include Morrison Construction, along with joint ventures from Balfour Beatty and Morgan Sindall, John Sisk & Son and Roadbridge, and Sir Robert McAlpine and Costain.

The £65m ($100.8m) contract includes widening the motorway, improving existing slip roads and building new west-facing slip roads to improve connectivity between the M9 and the new FRC.

The work also includes the installation of an Intelligent Transport System (ITS) to regulate the traffic between the FRC and Newbridge Junction, forming part of a 22km ITS corridor from M9 Junction 1a to the M90 Halbeath Junction.

The ITS will include overhead signal gantries along the corridor for lane control, variable mandatory speed control and traffic information to drivers through variable message signs.

The four consortia will submit final tender documents in 2011 for the contract, which will be awarded in July next year.