The A877 is a very short A-road, following the mostly residential Renfrew High Street, while the A8 dips south along Glebe Street. The road is dual-carriageway throughout, and was originally numbered as the A8. At the western end, the A877 passes between shops as it enters the town centre and then terminates on the A741, which goes north to the pedestrian only Renfrew-Yoker Ferry.
Back in 1922, this road was the original route of the A8. The route was moved before 1930, with the opening of the new Glasgow Road / Croft Street (now renamed as Glebe Street) route. Working on the assumed dating of the A878 in conjunction with the A876 Great Western Road extension, it would seem that the A8 was realigned in 1926-7. However, the fact that the dualling continues on the A877, and that pre 1930 buildings only line one side of the High Street at any one time, it seems that perhaps the A8 was at one time meant to come this way, and continue westwards, with a new bridge across the Black Cart Water? The big problem is that at the end of the road stands Renfrew Town Hall (above), which would have been a very big problem for any future 'expressway' like the Great Western Road to the north of the Clyde. The other problem to this thought is that taking a new expressway down the High Street of a county town would seem unlikely when there was open land not far to the south, and along the banks of the Clyde as well.