The B4178 is a short link road between the A449 and A4101 in Kingswinford, west of Dudley.
It starts on the A4101 (former B4177) at a set of traffic lights and heads northwest along Swindon Road, which marks the boundary of the urban area. The right of the road is built up whereas the left is comprised of fields (albeit still in the Metropolitan Borough).
Presently a roundabout is reached where the B4178 ends on the A449. Swindon Road continues ahead, now unclassified, to reach the Staffordshire village of Swindon.