The schools in my area you would be lucky to get anywhere near 30mph when kids are being picked up or dropped off,the roads are littered with chelsea tractors which are normally blocking at least half the road,but having said that I dont have a problem with a 20mph outside schools during term time and school hours.These could be notified by signs flashing the limit to let drivers know that school is in operation and therefore the limit applies.
What will almost certainly happen though is that they will stick cameras all over the place and people driving past a school at 25mph in the middle of the summer holidays will get done.

As for reducing the 30 limit to 20 overall,Imo it would be ludicrous,if your not capable of driving safely and stopping quickly or taking avoiding action if necassary at 30mph you shouldnt be driving.
As for motorways and other major roads,I dont think there should be any upper limit on them but I think we should have a seperate driving test that you have to pass after passing the normal test before being allowed to drive on them.This would include driving at high speed and demonstrating the ability to control the vehicle,drive in a safe manner,excercise lane discipline etc.
Then put as much freight as possible back on the railways,and happy days are here again.
