The route is predominantly single carriageway, though it is dual carriageway in parts. At the southern end lies the mile-long A8(M) motorway, a spur of the M2 motorway. From this point the road is dual carriageway to Coleman's Corner near the townland of Lisnalinchey, where the B95 exits for Ballyclare. There are two climbing lanes; each on either side of the village of Ballynure, where the A57 joins. The Harbour Highway, bypassing Larne, is dual carriageway, and includes a grade-separated junction with the A2.
There have been calls for decades to have the route upgraded. The most recent upgrade is the section of dual carriageway as far north as Lisnalinchey. In 2007 the Government of the Republic of Ireland announced that it was willing to allocate a total of €580 million towards road projects in Northern Ireland to include the completion of the dual carriageway between Belfast and Larne.