Where PlusNet leads…
... even the highways agency are at it now!
Photo taken by me on the M42 around Birmingham where they have "Active Traffic Management" in place. Always makes me chuckle - thought it was worth sharing 
I also like the references to "Variable Speed Limits Ahead" and "Congestion, slow down".
More info on this : http://www.roadtraffic-technology.com/projects/m42/