New speed limits

Last night I experienced the 'new' M11 for the first time. Entering the Motorway at Loughlinstown I was greeted by a big, fluorescent green sign indicating the new speed limit – 40MPH. I made every effort to maintain that speed, but, of course, I was being passed by people who hadn't heeded the new speed restrictions. Traveling at 40 when those who you're sharing the road with are doing 70 or more is totally unsafe. The new limit must be enforced or scrapped.

Also, why is there no "resume your normal speed" sign? I continued at 40MPH well past any obvious sign of construction - right to the end of the Motorway where 60MPH is the limit.