The B3402 is a short road to the west of Andover town centre. Originally part of the A342, the road became the A303 in 1933 before gaining its present number when that road was moved onto the bypass.
The route starts at the western end of the bypass at the northern roundabout of the A303/A342/A343GSJ and heads east along Weyhill Road. The road is signposted for local traffic only although it does start by going through an industrial estate before crossing a roundabout to become residential. After a small shopping area we go over the railway line.
The road continues into town, appearing more rural at one point as the houses are on side streets hidden behind trees. After another roundabout we merge into the town centre and end at traffic lights on the A3057 ring road.