Carbon Based wrote:...if a gantry sign were to display "too close" if triggered by sensors? Or would that just be distracting?
Distracting - Yes ...Of limited use - Undoubtedly; what you and I consider
too close or
tailgating, Joe-Average-Driver considers a normal following distance - If they notice the sign, they won't think the sign applies to them...
As for "Keep left" on managed sections, on the M6/M42 the information signs already display "Congestion. Use Hard Shoulder" but many drivers are reluctant or flatly refuse to us it.
The vast majority of drivers either don't notice the signs or, if they do, just ignore them - as they do the majority of all signage. Possibly a symptom of too much roadside information/signage.