The consultant has been confirmed winner for the 32 mile stretch of the A9 between the Pass of Birnam and Glen Garry.

Jacobs will start work on the section of the route nearest to Perth next month. The contract has an estimated value of £40m-£60m.

The award follows the £60m win in April by the joint venture of CH2MHill and Fairhurst for the Glen Garry and Dalraddy sections.

The third and final design contract to dual the A9 between Dalraddy and Inverness is expected to be awarded by the end of this year.

Transport Minister Keith Brown said: “I am proud that I am part of the only government to commit to dual the A9 between Perth and Inverness.

“This second major contract is another step forward for this mammoth project, and underlines our determination to bring forward benefits to road users as soon as we can.

“This multi-million pound investment also complements other work being progressed on the ground to improve the safety and performance of the A9, with the installation of average speed cameras  for implementation this October and ground investigation work is also progressing well on the Kincraig-Dalraddy scheme, which we expect to begin construction in 2015/16.

“Make no mistake, the Scottish Government wants to see improvements delivered as soon as possible and we are doing everything possible to bring forward elements of the scheme.

“We remain on track to deliver half of the 80 miles of new upgraded road by 2022, with completion expected by 2025.”