Smart Motorways ?

alastairq

Spot on.....volume of traffic !

Imagine how long the stationary queues would have been without the lower limits?

esuhl

One car braking on a motorway can cause a chain-reaction where cars travelling too close bunch together (sometimes coming to a complete stop).

Drivers' reaction times can mean that cars join the end of the tailback at a faster rate than they leave the front of the queue. This causes congestion that can last for hours after the original car braked.

Variable speed limits slow down the rate at which drivers join the tailback, so that the bunching can be eliminated and traffic can return to its free-flowing state more quickly.

The fact that the OP sees these variable speed limits, yet no obvious reason for them, demonstrates how quickly and effectively variable speed limits can ease congestion.

There's a quick video here that shows how bunching on motorways works:
https://www.youtube.com/watch?v=L45HwjzMu0g

DTDfanBoy

meer53 wrote: »

Not much use for the school run i'm afraid

You have to love the fact that Dad gets a helmet :T

Quiet_Spark

DTDfanBoy wrote: »

You have to love the fact that Dad gets a helmet :T

The trainers and tee shirt will be about as much use as having an ashtray fitted if he parts company with it though.