Motorway variable speed limit speeding fine, inadequate signage

Mildly_Miffed

MattMattMattUK said:

Mildly_Miffed said:

MattMattMattUK said:

The speed limit notification in my car (Model Y) seems accurate, I have not yet noticed it being wrong. It uses GPS roads and limits on Google Maps unless there are signs which it reads and amends. It seems to pick up the variable signs on motorways well ahead of needing to slow down, 100+ meters on the M25.

Still 200m or more after an attentive driver should have, though.

I very much doubt that most people can read a speed sign on an overhead gantry at 300 meters, that would be well over the DVLA vision requirements. 

As an example at 300 meters the sign would need to be 475mm higher to be readable with 20/20 vision, the acuity level for drivers from the DVLA is 6/12 that would mean the letters would need to be 875mm high, the height of the numerals on a variable speed sign on a motorway are 600mm high. Based on the legally required visual acuity that would mean that they should be readable at around 160-200 meters, however it is estimated that at least a third of people driving are below the required standard. 

It's literally the design standard.

prowla

user1977 said:

prowla said:

Isthisforreal99 said:

prowla said:

avinashvv said:

I was driving on cruise control and usually the car adjusts to speeds automatically after it passes the first sign. I was trusting this was ok as i got atleast one warning on my previous experiance. 

Car_54 said:

No "prior warning" is needed. Throughout the country, there are countless examples of a transition from NSL (60) to 30 with no such warning.

You say "The car in front of me suddenly breaked near the gantry and this forced me to change lanes for safety," Couldn't you have braked too? Were you driving too close to do so safely?

I didnt break hardly partly due to this and there was another car behind me I previously overtook.

Keep_pedalling said:

Looks like you had plenty of time to slow down. Also the cameras don’t become active immediately the speed limit appears on the gantry, there is always a delay so people who are actually paying attention are not caught out.

Sorry I think you are bang to rights on this one.

Yes, this limit was active 6 minutes ago, I know my defence is not based on this but about prior warning.

I would never trust the car to read or interpret speed limits correctly.

This.

My car occasionaly reads 30mph signs as 80mph and speaking to friends/neighbours I'm not alone.

I somehow don't think 'my car did it' would be a great defence.

My other (new) car doesn't appear to be able to read "(20)" signs painted on the road surface.

Are any cars meant to? Surely there are normal 20 signs too for them to read?

I did not see any roadside signposts with speed limits on the road in question.

The signs on the road surface are legal and normal (ref. TSRGD https://www.google.com/url?sa=t&source=web&rct=j&opi=89978449&url=https://tsrgd.co.uk/pdf/tsrgd/tsrgd2016.pdf , pg. 180), and therefore should be adhered to.

I sure hope that the car manufacturers products are indeed meant to follow them.

prowla

MattMattMattUK said:

Mildly_Miffed said:

MattMattMattUK said:

The speed limit notification in my car (Model Y) seems accurate, I have not yet noticed it being wrong. It uses GPS roads and limits on Google Maps unless there are signs which it reads and amends. It seems to pick up the variable signs on motorways well ahead of needing to slow down, 100+ meters on the M25.

Still 200m or more after an attentive driver should have, though.

I very much doubt that most people can read a speed sign on an overhead gantry at 300 meters, that would be well over the DVLA vision requirements. 

As an example at 300 meters the sign would need to be 475mm higher to be readable with 20/20 vision, the acuity level for drivers from the DVLA is 6/12 that would mean the letters would need to be 875mm high, the height of the numerals on a variable speed sign on a motorway are 600mm high. Based on the legally required visual acuity that would mean that they should be readable at around 160-200 meters, however it is estimated that at least a third of people driving are below the required standard. 

I don't know at what distance I can read those signs, but I can sure tell that they are active and I should be prepared to take action.

Things like the brake lights showing on other cars might also be a good hint.

user1977

prowla said:

user1977 said:

prowla said:

Isthisforreal99 said:

prowla said:

avinashvv said:

I was driving on cruise control and usually the car adjusts to speeds automatically after it passes the first sign. I was trusting this was ok as i got atleast one warning on my previous experiance. 

Car_54 said:

No "prior warning" is needed. Throughout the country, there are countless examples of a transition from NSL (60) to 30 with no such warning.

You say "The car in front of me suddenly breaked near the gantry and this forced me to change lanes for safety," Couldn't you have braked too? Were you driving too close to do so safely?

I didnt break hardly partly due to this and there was another car behind me I previously overtook.

Keep_pedalling said:

Looks like you had plenty of time to slow down. Also the cameras don’t become active immediately the speed limit appears on the gantry, there is always a delay so people who are actually paying attention are not caught out.

Sorry I think you are bang to rights on this one.

Yes, this limit was active 6 minutes ago, I know my defence is not based on this but about prior warning.

I would never trust the car to read or interpret speed limits correctly.

This.

My car occasionaly reads 30mph signs as 80mph and speaking to friends/neighbours I'm not alone.

I somehow don't think 'my car did it' would be a great defence.

My other (new) car doesn't appear to be able to read "(20)" signs painted on the road surface.

Are any cars meant to? Surely there are normal 20 signs too for them to read?

I did not see any roadside signposts with speed limits on the road in question.

The signs on the road surface are legal and normal (ref. TSRGD https://www.google.com/url?sa=t&source=web&rct=j&opi=89978449&url=https://tsrgd.co.uk/pdf/tsrgd/tsrgd2016.pdf , pg. 180), and therefore should be adhered to.

No, they need a "normal" sign at the start of the limit to be enforceable - you'll see the notes saying schedule 10 part 4 general direction 6 applies i.e. "If the road marking is placed to indicate where a maximum speed limit commences, it must be placed in conjunction with an upright sign provided for at item 1, 5, 6 or 8 of the Part 2 sign table."

MattMattMattUK

prowla said:

MattMattMattUK said:

Mildly_Miffed said:

MattMattMattUK said:

The speed limit notification in my car (Model Y) seems accurate, I have not yet noticed it being wrong. It uses GPS roads and limits on Google Maps unless there are signs which it reads and amends. It seems to pick up the variable signs on motorways well ahead of needing to slow down, 100+ meters on the M25.

Still 200m or more after an attentive driver should have, though.

I very much doubt that most people can read a speed sign on an overhead gantry at 300 meters, that would be well over the DVLA vision requirements. 

As an example at 300 meters the sign would need to be 475mm higher to be readable with 20/20 vision, the acuity level for drivers from the DVLA is 6/12 that would mean the letters would need to be 875mm high, the height of the numerals on a variable speed sign on a motorway are 600mm high. Based on the legally required visual acuity that would mean that they should be readable at around 160-200 meters, however it is estimated that at least a third of people driving are below the required standard. 

I don't know at what distance I can read those signs, but I can sure tell that they are active and I should be prepared to take action.

Things like the brake lights showing on other cars might also be a good hint.

It might be a good hint to people with a level of common sense, but when I drive on the M25 and the variable speed limit signs are visible most people seem to drive as fast as they can until a few tens of meters before them, then slam the brakes on just as they go underneath them.

Readability will be one issue, especially for those with visual acuity below the legally required standard, although it is largely secondary to good road craft, which is sadly lacking.

TooManyPoints

Readability will be one issue, especially for those with visual acuity below the legally required standard, although it is largely secondary to good road craft, which is sadly lacking.

Indeed.

Quite a few posts are seen here and elsewhere regarding this issue.

Signs on motorway gantries are extremely bright and even in bright daylight they can be seen (if not completely deciphered) from a long distance, far in excess of any required to shed (what is usually at most) 30mph.

When a competent and careful driver sees one in the distance – especially if it is the first of a restricted stretch - they will usually be prepared to adjust their speed well before they are close enough to read the number displayed.

This thread demonstrates precisely the lack of road craft which is abundant. Drivers plough on (especially if they have some sort of cruise control set) at – or usually in excess of – the limit, which they view as a target speed which must constantly be maintained, rather than a maximum.

Then you get posts like this, moaning that they did not get "enough notice" to lose a mere 20mph.

prowla

user1977 said:

prowla said:

user1977 said:

prowla said:

Isthisforreal99 said:

prowla said:

avinashvv said:

I was driving on cruise control and usually the car adjusts to speeds automatically after it passes the first sign. I was trusting this was ok as i got atleast one warning on my previous experiance. 

Car_54 said:

No "prior warning" is needed. Throughout the country, there are countless examples of a transition from NSL (60) to 30 with no such warning.

You say "The car in front of me suddenly breaked near the gantry and this forced me to change lanes for safety," Couldn't you have braked too? Were you driving too close to do so safely?

I didnt break hardly partly due to this and there was another car behind me I previously overtook.

Keep_pedalling said:

Looks like you had plenty of time to slow down. Also the cameras don’t become active immediately the speed limit appears on the gantry, there is always a delay so people who are actually paying attention are not caught out.

Sorry I think you are bang to rights on this one.

Yes, this limit was active 6 minutes ago, I know my defence is not based on this but about prior warning.

I would never trust the car to read or interpret speed limits correctly.

This.

My car occasionaly reads 30mph signs as 80mph and speaking to friends/neighbours I'm not alone.

I somehow don't think 'my car did it' would be a great defence.

My other (new) car doesn't appear to be able to read "(20)" signs painted on the road surface.

Are any cars meant to? Surely there are normal 20 signs too for them to read?

I did not see any roadside signposts with speed limits on the road in question.

The signs on the road surface are legal and normal (ref. TSRGD https://www.google.com/url?sa=t&source=web&rct=j&opi=89978449&url=https://tsrgd.co.uk/pdf/tsrgd/tsrgd2016.pdf , pg. 180), and therefore should be adhered to.

No, they need a "normal" sign at the start of the limit to be enforceable - you'll see the notes saying schedule 10 part 4 general direction 6 applies i.e. "If the road marking is placed to indicate where a maximum speed limit commences, it must be placed in conjunction with an upright sign provided for at item 1, 5, 6 or 8 of the Part 2 sign table."

Thanks for that - appreciated!

There is potential for weasel words there, whereby the road markings don't mark where the speed limit "commences".

TooManyPoints

There is potential for weasel words there, whereby the road markings don't mark where the speed limit "commences".

It commences where the relevant TRO says it commences. It is the TRO which determines the exact location, not the signs.

The limit must then be "adequately conveyed". Signs painted on the road surface alone are not adequate.