Yellow jackets on the A1M today

[paul-wh]

Anybody got any idea what the people with yellow jackets were doing on the A1M today. I joined at The Clock Welwyn and left at South Stevenage and there were yellow jacketed people everywhere, even on one of the bridges. I am sure it was some sort of survey but they certainly made people slow down to 70.

They were there this morning and still there this evening