Advance Warning of Junctions

[Bryn666]

Practical realities make the placement of signs impossible to apply rigid rules to.

Thanks to gantry designs now being so ridiculously big that the foundation alone is the size of Luxembourg locating the damn things is harder than ever.

[Vierwielen]

This one is 1½ miles rather than 1 mile on the M50 because the road is about to pass over the River Severn.

https://goo.gl/maps/KcgJrbJ2pN9gc4xA9

This one at Port Talbot on the M4 is for ⅔ mile.

https://goo.gl/maps/DN4TivxPfbVRNYK59

I think that should be the absolute minimum signed distance for junctions (either all-purpose roads or motorways. Perhaps round it up to 1200 yds/1100m.

½-mile simply isn’t enough. Even if you’re paying full attention to the road ahead.

If there were an absolute minimum, it would have to depend on the maximum number of carriageways on the motorway. Also, it is normal for the first sign to display the primary locations served by the junction and the second the road numbers served by the junction.