The value of the contract could double, as there is the possibility of an extension to 10 years.
If the deal clears the final legal hurdles, it will mean that Balfour Beatty Living Places will be responsible for the design and implementation of highway maintenance and improvement works, winter gritting, street lighting, traffic signals and bridge works throughout the county.
Approximately 200 Suffolk County Council and Ipswich Borough Council staff will be transferred under TUPE rules. The new arrangement will come into effect on 1 April 2013.
The contract is expected to achieve savings of £2m for the council in 2013-14.
Balfour Beatty has committed to improving the availability of information about work on the highway as well as using local companies and taking on local apprentices.
Balfour Beatty CEO Ian Tyler said: “We are delighted to be chosen preferred bidder by Suffolk County Council for the highways maintenance contract. Once again Balfour Beatty Living Places has shown that it can deliver a high quality service to local authorities at a price that is right for the taxpayer.
“As well as continuing to provide excellent highway services, we will also be concentrating on supporting the local economy through opportunities for local people, especially young people, offering apprenticeships and enhancing skills. We will also be employing local supply chain within the county.”