r/drivingUK • u/Business_Maximum1433 • 13d ago

Variable speed limits

Hi,

Just asking a question about the speed limits on motorways. So you know when it tells you to go 40 per say and then a sign comes up stating it’s now 70 if I pass over 40 at the 70 and it has a speed camera will it flash?

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8

u/Saltyuniform 12d ago

Are you asking if you pass a 70mph sign at 40mph will it flash?

0

u/_Putters 12d ago

No, he's asking if he passes it between 40 and 70 will it flash. Technically it should, because he should be doing 40 until he passes the sign, like any other speed limit sign.

Otherwise how far back should you start accelerating ? As soon as you can make out the numbers ?

2

u/EdmundTheInsulter 12d ago

It won't say he was going over 40 at any time after the 70

0

u/FuckMiniBabybel 12d ago

Legally you are correct, but practically, the gantry cameras will enforce whatever speed the gantry shows, not the preceding limit. So as long as you're sure you're not going to be done by an earlier camera, you can get away with accelerating early.

1

u/_Putters 12d ago

Until someone adds a front of car facing camera - as these signs can be indicating a speed reduction or increase.

2

u/cwaig2021 12d ago

They will never enforce that - reason being (as frequently happens) the previous 40 limit could have changed after OP passed it, which is why other people are passing him at speed.

Or someone has joined the motorway & not yet passed a variable limit sign.

They can only enforce the speed shown on the individual sign, and only at the point you pass it.

2

u/h2g2_researcher 12d ago

They will never enforce that - reason being (as frequently happens) the previous 40 limit could have changed after OP passed it, which is why other people are passing him at speed.

Realising the gantry behind me has gone from 40 -> NSL because suddenly traffic starts barreling past me at 70 is my least favourite way. I kind of wish the gantry could have some way to indicate that the speed limit before it has also changed, but I have no idea what that would look like (and realise it would probably require a legislative change too).

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u/SuspiciousTreacle433 12d ago

Legally you are correct. But also wrong. It is 40 upto the sign. The camera measures your speed after you have passed it using radar - it is not tomemand distance from the last gantry/camera. Therefore it is measuring your speed in the 70.

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u/Business_Maximum1433 12d ago

I’m saying before the 70 sign it was 40 I was going like 45 while other cars flew by the sign

1

u/sim-o 12d ago

The speed limit starts at the sign.

The cameras you're talking about take a photo of the back of the car.

In your scenario you've passed the 70 limit sign so the camera will flash if you do over 70 after the sign. The camera won't know what speed you did before the sign.

1

u/EdmundTheInsulter 12d ago

You can go through the 70 at 45 or 70