Variable Speeds - Going Down!

[mpwilson99]

Just a thought while I was driving along the M25 yesterday...

I was approaching a gantry laiden with speed cameras and the enforced speed limit was 60 mph. I was doing just about that mph at the time.

I wasnt far from being underneath it when the speed limit dropped by 10mph to 50mph, thus now im about 3mph over the tollerance level. ( 50mph + 5mph (10%) +2mph)

Thankfully for me, I just had time to slam on the anchors and slow down to getting between 50 - 57mph.

I dont think the car in front had much chance though !

I guess the question im thinking, is do the cameras have a reset time after the signs change to a new lower limit?

MPW
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[BaggieBoy]

There is apparently a "grace" period after a reduction of the VSL, I've heard 45 seconds quoted.

[JockTamsonsBairn]

There is a grace period, to avoid this type of potential accident. I can't remember how long, though.
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[GerryC]

According to this post on Pepipoo which quotes the Statutory Instrument for the M6 VSL zone, if it changes, the speed limit for you is what was shown 10 seconds before you get to the sign.

This should cover any change as you approach the sign - which you may or may not see. You'll also have an idea what the next sign will say if you did see it change.
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Gerry
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[DennisN]

I confess I've wondered the same myself when the same happened to me on the M25 yesterday (not for my own benefit, you understand, merely for the benefit of people like you with big fast cars! ). I bet they really must have a time lag, but how long, is the question? The sensible lag would be the time it takes to travel the difference between the first and second speeds, simply by taking your foot off, rather than chucking the anchor over the side in desperation. But I guess they take the easy option and simply add nn seconds when they press the switch (probably excessive delay to cope with changes from derestricted to 40mph in one jump?). Being of little brain, I have absolutely no idea how many seconds that would be. But in any scenario, if you're over the signed limit, you get clobbered, whether they get the time delay right or wrong - can you imagine the fun of trying to contest that in court?
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Dennis

If it tastes good - it's fattening.

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[PaulB2005]

According to SpeedTrap the M25 grace period is 5 minutes which matches to the 3-5 minutes figure i found last time this came up.

[DennisN]

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