Work includes dualling the single carriageway road between Willerby and Cottingham in East Yorkshire and rebuilding four roundabouts. The project is expected to take a year.
Stephen Parnaby, leader of East Riding of Yorkshire Council, said: “The council is delighted to announce that this scheme is now under way which, as well as improving the area’s transport infrastructure, will safeguard jobswithin the construction industry.”
The council is providing £2.3m of the funding, with the balance from the Department for Transport.
Jackson regional manager Andy Burton said: “We’re really pleased to be involved with this scheme which will significantly improve journey times for motorists, and benefit the East Riding as a whole.”