A few years ago in Barcelona they put in place a maximum 80kph limit in the metropolitan area; which included the many multi lane ring roads.
The stated reason was to reduce collisions and pollution.
Pollution was not significantly affected and death/serious injuries increased by more than 40 percent.
All the main roads now have variable speed limits depending on the traffic levels - from perhaps 50kph to the upper limit of 120.
Make of it what you will but the Barcelona experiment of blanket lower speeds does not seem to have worked for either of the stated purposes.
For those moaning about lower limits and speed though the speed limits in that city are now more generous the entire ring road system has average speed cameras
and these are also being rolled out along the entire length of all the motorways in Catalunya.Some you win and some you lose; but mostly you lose
