Motorway lane restrictions and use of matrix
Motorway lane restrictions and use of matrix
Author
Discussion

towman

Original Poster:

14,938 posts

262 months

Saturday 31st July 2004
quotequote all
One to ponder:

Caught up on M25 the other night while they changed the contraflow near Heathrow. M/way restricted to lane 1 only, with red lights flashing above lanes 2 & 3 . Given that the gantries also hold cameras, why is it not possible to prosecute those who are too self important (or ignorant) to obey a "do not pass" indicator. (I know thats not the technical term for what flashing reds indicate, but you know what I mean). Can`t they set the camers to trigger at 10mph for example, so everyone who passes gets flashed?

Steve

supraman2954

3,241 posts

262 months

Saturday 31st July 2004
quotequote all
Maybe someone will correct me, but I think the red cross means 'lane closed', as opposed to "do not pass".

A recent post could indicate that others would disagree with you (can't remember the thread name).

puggit

49,441 posts

271 months

Saturday 31st July 2004
quotequote all
Highway code says "Do not proceed further in this lane"
www.highwaycode.gov.uk/signs01.shtml

supraman2954

3,241 posts

262 months

Saturday 31st July 2004
quotequote all
So how does one interpret:
highwaycode said:
lane closed to traffic facing the sign
?

And what if all the traffic is moving at considerable speed and you are in the lane that shows this sign as you approach the gantry, should you:

1) filter in when safe to do so, although you may have to pass the gantry to do this safely

2) stand on the brake pedal hoping that you don't cause an accident?

towman

Original Poster:

14,938 posts

262 months

Saturday 31st July 2004
quotequote all
supraman2954 said:
Maybe someone will correct me, but I think the red cross means 'lane closed', as opposed to "do not pass".

A recent post could indicate that others would disagree with you (can't remember the thread name).


Apologies for my bad use of terminology. I was getting at "Do not pass this sign in this lane", not "do not overtake"

Steve

towman

Original Poster:

14,938 posts

262 months

Saturday 31st July 2004
quotequote all
supraman2954 said:
So how does one interpret:

highwaycode said:
lane closed to traffic facing the sign

?

And what if all the traffic is moving at considerable speed and you are in the lane that shows this sign as you approach the gantry, should you:

1) filter in when safe to do so, although you may have to pass the gantry to do this safely

2) stand on the brake pedal hoping that you don't cause an accident?


My thoughts are that you should be able to see the sign from some distance, therefore option 1. Unless of course the sign illuminates just as you approach.

I also believe that once the matrix has been set, previous gantries will show a filter arrow away from the closed lane.

Steve

towman

Original Poster:

14,938 posts

262 months

Sunday 1st August 2004
quotequote all
Still looking for an answer on this one!

Flat in Fifth

47,917 posts

274 months

Thursday 12th August 2004
quotequote all
towman said:
Still looking for an answer on this one!


Passing the red cross has the same penalty as failing to stop at a red traffic light.

I dunno about the possibility to convert the speed camera to a red light camera, but nothing is impossible one supposes.

Re your question regarding if it changes just as you approach. Surely the same issue arises if the speed limit changes. There must be some time delay built in.

Anyway subsidiary question.

Re the new gantry signs going up on the M42 (M6-M40 section) subject the never ending roadworks.

I think these signs are part of the new system which will use the hard shoulder as a running lane in busy times.

However the gantry signs look a lot like the M25 signs, ie I expect there to be variable limits applied, eg as in 50 surrounded by red circle.

Can't tell yet for sure but does anyone else know, I'll get my contacts checking in the meantime.

Nightmare

5,277 posts

307 months

Thursday 12th August 2004
quotequote all
Flat in Fifth said:

towman said:
Still looking for an answer on this one!

Re your question regarding if it changes just as you approach. Surely the same issue arises if the speed limit changes. There must be some time delay built in.

there is...cant remember how long (one of the guys who used to be on erhe designed the system!!!)...I know Ive gone thorugh one at around 60 about 2 seconds after it flicked to 40 and didnt get camera'd....

N

philthy

4,697 posts

263 months

Thursday 12th August 2004
quotequote all
The variable speed limit cameras on the M25 have a sixty second delay before snapping speeders after a speed limit change.
I know someone who used to work on them.
Phil

Peter Ward

2,097 posts

279 months

Thursday 12th August 2004
quotequote all
I'm pretty sure I've read that when the hard shoulder is used as a lane then the speed limit will be reduced to 50. Of course I'm sure there will be lots of other occasions for the controllers to reduce the speed limit to 50 or less.