M32 motorway B4469 providing access to Horfield. Midway through, a speed limit begins. The motorway continues further south and ends just beyond junction 3, north of St Paul's. A dual carriageway continues as the A4032 into the centre of Bristol, with a speed limit. The M32 is a trunk road, therefore its maintenance and upkeep is paid for by Highways England, the national roads authority. Most of the road has two lanes in each direction, though an extended sliproad north of junction 2 provides a climbing lane, and the short section between junction 1 and the M4 has three lanes both ways.
M4 relief road and narrows to a restricted two-lane section through the Brynglas Tunnels, where heavy congestion occurs at peak hours. A variable speed limit is in place between junctions 24 and 28. M4 sliproads at Junction 25 (Caerleon Road) are diverted to reduce traffic through the tunnels. M4 Westbound traffic joining at Junction 25 is diverted via Junction 25A/A4042 (Heidenheim Drive)/A4051 (Malpas Road) to Junction 26. Similarly eastbound traffic wishing to exit at Junction 25 is diverted from Junction 26 via the A4051/A4042/Junction 25A. This adds to congestion on Malpas Road and other local roads near Newport city centre at peak times.