Symmetrical Speed Limits?
Discussion
As far as I can tell, speed limits are always symmetric on either iside of a road - where it changes from NSL to 30 on one side will be the spot it changes from 30 to NSL on the other.
I've wondered about this for a while, is it an enforced standard or convention, and why?
I can easily think of a number of places where this scheme isn't ideal - the town which where I live has a steep downhill dual carriageway that was reduced from NSL to 40 many years ago after an HGV embedded itself in the roundabout at the end, the uphill side has no reason at all to be 40 other than symmetry. Think of all those villages where the transition from 30 to NSL happens way outside the village - that's so that the NSL to 30 on the other side is far enough outside the village that people actually slow down by the time they reach the built up bit.
What's going on then?
I've wondered about this for a while, is it an enforced standard or convention, and why?
I can easily think of a number of places where this scheme isn't ideal - the town which where I live has a steep downhill dual carriageway that was reduced from NSL to 40 many years ago after an HGV embedded itself in the roundabout at the end, the uphill side has no reason at all to be 40 other than symmetry. Think of all those villages where the transition from 30 to NSL happens way outside the village - that's so that the NSL to 30 on the other side is far enough outside the village that people actually slow down by the time they reach the built up bit.
What's going on then?
A666 St Peters Way, Bolton...
Northbound has a drop from a 50mph limit to 40 here
whereas
Southbound the 40 limit changes to a 50 a couple of hundred yards further North.
Northbound has a drop from a 50mph limit to 40 here
whereas
Southbound the 40 limit changes to a 50 a couple of hundred yards further North.
So we are saying always symmetrical on a single carriage way, not always on a dual.
I can see the logic on that stretch of the A50 - often long queues approaching the M1 junction.
Same is true approaching the tolls on the M4 Severn Bridge I think, 50 limit for safety, but NSL the other side where there are no tolls (it's free to leave Wales).
I can see the logic on that stretch of the A50 - often long queues approaching the M1 junction.
Same is true approaching the tolls on the M4 Severn Bridge I think, 50 limit for safety, but NSL the other side where there are no tolls (it's free to leave Wales).
QBee said:
So we are saying always symmetrical on a single carriage way, not always on a dual.
Correct. I believe it's mandated that the limit is the same in each direction of a single carriageway, but they're allowed to be different on dual. It's unusual, but you do occasionally find dual carriageways with asymmetric limits - Park Lane is not unique.See this thread. Consensus was that you can have different limits either side of dual-carriageways but not single carriageways. Though as I posted, roadworks may be an exception .
M60 at Bredbury (between junctions 26 and 25) is 70 in the anti-clockwise direction and 50 in the clockwise direction.
All because some chavs didn't know how to drive a tightening radius bend at motorway speeds and above.
Had about 4 accidents there in a matter of a couple of years, mostly due to the fact that they tried to take the bend at about 90, which when you have a fully loaded saxo, and not so smooth inputs to the steering is only going to end up messy!
All because some chavs didn't know how to drive a tightening radius bend at motorway speeds and above.
Had about 4 accidents there in a matter of a couple of years, mostly due to the fact that they tried to take the bend at about 90, which when you have a fully loaded saxo, and not so smooth inputs to the steering is only going to end up messy!
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