The road measures 8.87 miles long and would take a car obeying speed limits 20 minutes to travel its length.
The B4278 is a B Road and is located in the Zone 4 Highways Region.
This is a true long-distance route, journeying through numerous towns like Tonyrefail, TONYPANDY, Penrhiwfer, Williamstown, Trealaw, and PORTH.
The road connects Mid Glamorgan and Mid Glamorgan.