	The road is a dual carriageway, most with two lanes each way, but there are two dual three-lane sections: on the Newmarket bypass (between Junctions 36 and 38) where it runs concurrent with the A11, and a short stretch between the Girton Interchange and Bar Hill. There are three at-grade junctions: with the B663 at Bythorn in Cambridgeshire (junction 15); at the Leighton Bromswold turn a few miles to the east (junction 17); and at the Dockspur Roundabout at the edge of Felixstowe (junction 60).