At least, as mentioned above, it's not a blanket reduction on single carriageways, but I do wonder how it's going to work.
Take the A82 Glasgow - Inverness. This is a very dangerous road in places but not in others. The section from the end of the dual carriageway is currently 60 (although that speed is not normally attainable during the main summer season)! From Tarbet to just north of Inverarnon - no-one in their right mind would contemplate driving at 60 unless one was assured of a completely empty road, no potholes, etc!, but after the climb up to Glen Falloch the road is good and has clear views. From Crianlarich to Tyndrum, there's only one safe spot to overtake and then it's up on the run to Bridge of Orchy and over Rannoch Moor where there are plenty of straight stretches until you hit GlenCoe - even then there's overtaking opportunities at the bottom end before hitting GlenCoe village. From the village right through to Fort William and beyond - forget it - it's lethal! From the Fort to Spean Bridge there's a couple of opportunities (if you know them) and more after the Commando Memorial above Spean Bridge. After that, there's three long straights before Fort Augustus and then - unless you really know the road very well, virtually zilch till you get to Inverness. My betting is they'll simply 50 the whole thing and that is going to be a recipe for disaster for the Highlands & Islands economies, tied in as they are to long distances and ferry times. It will mean (as mentioned previously) additional costs to individuals having to do long journeys and will also increase the costs of goods and services.
Furthermore, it will increase frustration amongst drivers (already evident!) - particularly those who have a clear straight road in front of them and they're not allowed to overtake a vehicle whose driver, in fairness, doesn't know the road and brakes down to 20 for every bend.
Reducing the speed limit to 50 may well improve emissions if everyone stuck to it (but that also depends on one's vehicle's gearing) but Rolebama made the point that it's policing that's needed to get the illegals off the road (sorry, paraphrasing). I'm also acutely aware that I spend more time checking my speedo at 50 than at 60 - I've been doing the eco driving thing - and that's not good either as those fractions of a second can add up - you spend more time worrying about the law than the situations around you.
I'm not against reducing road deaths and injuries - far from it. I'm raising questions. I wouldn't presume to comment on urban roads - just don't know.
Finally, as you're all probably heartily sick of me :rolleyes: - single track roads will probably be made to be 20. The general concensus (as this was leaked before the Budget speech) is that Westminster can do what it likes - we'll drive to the conditions - perhaps if everyone did, we wouldn't need all these big brother interventions?