From the Daily Mail.
In a move which will surely offend all of those who feel the need for speed, the Highways Agency are considering a 60mph limit on our local stretch of the M1 at busy times. This will reduce congestion and pollution apparently and is now out for consultation.
As a fully paid up member of the Institute of Advanced Motorists I would give my cautious support, but a simple straw poll of friends and acquaintances suggests I’m in a minority!
Have your say here.
LoveDinnington.com 
Funny because they were talking about increasing the speed limits to 80mph. I think we need to look at why our roads are so full, couldn’t more people work from home. Can’t we get more people into our town and cities, using the bus and rail. The rail line through Anston could be opened up to the public for little cost and run Hybrid trams into Sheffield. We could transport more of our goods by rail and then distribute locally.
So what is the difference in smog levels at 60 mph and 70 mph, not very much I suspect. This has nothing to do with smog levels, this is about speed controlled areas, similar to the system they have around Birmingham. They just want to restrict speed for traffic control at peak times. Watch the steel frames go up over the motorway, with the electric signs that you can alter the speed and he presto, you have a variable speed control zone. Expect to be controlled down to 40mph at peak times, especially around the Sheffield Park Way area.