Work is scheduled to start at the end of 2015 and be completed in spring 2017.
More than 22,000 vehicles pass through the village of Broughton on the A6 every day. The bypass will create a new route from the roundabout at Junction 1 of the M55 to the A6 north of the village. It is expected to remove 90% of the traffic form the village centre.
Lancashire County Council leader Jennifer Mein said: "The plans are now moving at pace, with the road scheduled to open in spring 2017. The county council is currently working with the contractor to develop a detailed schedule for the work, which will be shared with the local community and other people who use of this crucial stretch of the transport network."
Hochtief (UK) Construction managing director Sally Cox said: "Our team is eager to get started and make the delivery of this scheme a complete success for the community in Broughton."
The building of the road will also support a new housing development at Whittingham Hospital, where approval has been given for a development of 650 homes, and 9,000m2 for business use. 150 new homes will be built in the first phase.
Taylor Wimpey is already working on the site, and other developments are planned in this area.