I believe it is widely accepted that the status of highways in the UK is reflected by trunk, primary and secondary roads (primary route, non-primary route, and B-road). The class of road may not necessarily reflect the use, as here, but nonetheless it is still a primary route.

There is a green sign at the Cornwallis Terrace end, but only parking signs at the southern end. These are always white regardless of primary status.

The road is not oneway. There is no bus lane running opposite to the direction of traffic, just a bus gate at the northern end restricting access. This is represented by turning restrictions mapped at the station junction. Drivers will not be routed along the road in the southern direction due to these.

Devonshire Road and South Terrace are not A or B-roads. They should not be trunk, primary, or secondary ways.