Negligence is an understatement, pure idiocy! Driving at that speed alone in the public realm is extremely dangerous, let alone through a restricted zone where other drivers are abiding and workers may be present.
These roadworks have been in place for quite a while now, most people abide by the limit, although I frequently experience drivers flying past me at what must be 70+, which always begs the question....do the average speed cameras clock you or do they act as symbols and imply traffic enforcement? Some drivers claim that each camera is attributed to a single lane, therefore you can change lanes and distort or void the reading. Not sure about that one , but what I am sure about is everyday day somebody passes me well over the limit?
Kind of off topic, but many of my friends, some of whom are taxi drivers claim that 'most, if not all static cameras in our city are switched off.' I do have first hand experience with one camera in particular, one very close to home. Driving past at the limit I am frequently passed by many who fly through it, including emergency vehicles and it does not flash! Again suggesting that a lot of cameras act as mere visual deterrents. I am looking forward to the day it becomes active again, that way people may abide by speed limits.