The B491 is a short route in the Acton area of west London. The road was originally unclassified, except for the southern end which was part of the original line of the B409, but going by its number the road gained Class II status in the mid-1920s.
It begins at traffic lights on the A490 and heads east along Southfield Road before zigzagging into the north-south The Avenue. At a mini-roundabout on the corner of Chiswick Common the B409 is met and there's a short multiplex alongside the Common to the next mini-roundabout. We then continue on Turnham Green Terrace past Turnham Green station and under the District and Piccadilly Lines before leaving the Common behind. It's not long before we end at a further set of lights on the A315 Chiswick High Road.
