Work has started to improve safety at an accident blackspot on a main link route to east coast ports.
The £32m construction scheme has started on a notorious stretch of the A14 near Stowmarket, one month ahead of a planned start date.
A 2.3 mile (4km) two-lane dual carriageway is to be built between Haughley New Street and Stowmarket.
A new junction at Tot Hill is designed to give locals safer access to the A14. Work is expected to take 19 months.
The stretch of road known as the Haughley Bends, near Stowmarket, is well-known for accidents and traffic jams despite a 50mph speed limit.
Roads minister Dr Stephen Ladyman said: "This is good news for everyone who uses the A14.
"The road is heavily used by traffic heading to and from the east coast ports of Felixstowe and Harwich, and the current route has a poor accident record.
"The new dual carriageway will improve safety for all road users and the new junction will give better access from the A14 for the villages of Haughley, Haughley New Street and Harleston."
The scheme includes safer crossing points for pedestrians, cyclists and horse riders.
The variety and amount of wildlife in the area have been assessed and will be regularly monitored by a team of experts.