Dangerous variable speed limits on M4 Newport

luckwudaveit

Wig wrote: »

Infact I like my idea of flashing red lights so much I think they should be flashing (red lights) all the time while there is a speed limit inplace.

Flashing red lights are commonly understood to mean 'stop' on a motorway, or 'do not proceed further in that lane'.

I agree that to reduce down from 70 to 60 to 50 would be sensible, but with the sightlines on a motorway and with due attention, motorists should be able to safely reduce their speed by 20mph after seeing a lit speed limit sign.

Lum

Wig wrote: »

You're probably replying to adamc, as I don't know if it suddenly came on for me or not. but the reaction from drivers is going to be the same. Whether they see it come on or just notice it suddenly as they approach.

I do actually agree with you. I was just pointing it out so that next time you (or anyone else who reads this thread) see it suddenly switch on in front of you, you might not feel the need to suddenly slam on and instead can just coast down to 50. Safer and saves money

I wonder if they were rebooting the system or something since that westbound tunnel is a perma-50 limit. I commute through that tunnel every weekday, and in fact have just been through it about half an hour ago.

adamc260

Someone mentioned a 'grace period' but how long is it? Try telling that to a ticket =/

kazza80_2

:oI have just travelled back from Cardiff tonight and passed through the Newport tunnel in torential rain and couldn't see any 50mph speed restrictions?!!! I actually panicked as I was expecting them due to the weather conditions! I am now worried thinking I missed them? but after reading the above I am now beginning to believe that there probably weren't any?!

Certainly on my journey to Cardiff the Westbound restrictions were on this morning.

It's mad, and counterproductive when the system is unpredictable.

SHIPSHAPE

kazza80 wrote: »

It's mad, and counterproductive when the system is unpredictable.

The clue is in the many signs dotted along the M4 around that stretch, they are 'variable,' the limit changes.

How can I notice these many signs, thus be prepared, yet you cannot?

Badger_Lady

Lum wrote: »

1) There is a grace period after the limit changes for the camera to activate specifically to avoid the kind of situation you describe

I didn't know this, but I had always assumed it to be true... a couple of times the speed limit has suddenly changed right in front of me - I choose to slowly, safely make the transition rather than panic. I've always maintained that I would take the safe option and then dispute it in court if I was ever challenged for being over the limit.

But of course when something suddenly flashes up saying effectively "you are driving too fast and we will get you for it, mwahaha!", a lot of drivers will react more severely than they should.

Perhaps the grace period should be made more transparent - I'm thinking of the equivalent of the 'flashing green man' on a Pelican crossing that tells you it's about to change. The variable speed limit could go into 'warning: speed changing' mode before it actually goes into 'new speed' mode..?

Dunno, I'm not a traffic designer! But those of us in the know can at least show best practice and be very aware of those around us behaving strangely so we can adjust accordingly.

kazza80_2

SHIPSHAPE wrote: »

The clue is in the many signs dotted along the M4 around that stretch, they are 'variable,' the limit changes.

How can I notice these many signs, thus be prepared, yet you cannot?

I did see a National Speed limit sign a few miles previous to the area I know has been a 50mph speed limit but it was the weather conditions that has made me assume it should be 50mph. I usually am very observant, but the weather conditions were extremely poor. I will just have to wait and see.

Notmyrealname

Wig wrote: »

They even warn you of the limit change on the A470 as you head into Cardiff, plenty of warnings signs of an imminent reduction in speed ahead as it is a 70mph road.
.

Meanshile outside of Wales in the rest of the UK, very few places give advanced warning of speed limit changes - you get to find out when you see the sign.

tripled

Notmyrealname wrote: »

Meanshile outside of Wales in the rest of the UK, very few places give advanced warning of speed limit changes - you get to find out when you see the sign.

The fact they don't do it doesn't mean it isn't good practice. Also there is a difference between a well sighted static sign and one possibly being turned on in front of you, or being obstructed and coming into view late for whatever reason.

How do they do it on the M25 and other motorways with variable speed limits? I assume it's the same?

Perhaps they should show the advisory limit for 30 seconds (orange flashing lights and the speed), then switch to the mandatory variable one? Would seem like a good compromise.

Red isn't practical as you aren't allowed to pass them as far as I am aware, just like at a level crossing, bridge, etc. Only time I've seen red flashing lights on a motorway is when lanes are closed or the motorway is shut down altogether.

funkycoldribena

I think what'll happen in the end is we'll all have to have some kind of safety man to walk in front the car,maybe he could carry a warning stick, with say something red attached to it?