Caught speeding in a 30mph, 25m after National Speed Limit |
Caught speeding in a 30mph, 25m after National Speed Limit |
Wed, 14 Aug 2019 - 14:48
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#1
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Member Group: Members Posts: 29 Joined: 26 Aug 2011 Member No.: 49,245 |
Got caught doing 39mph in a 30mph zone by a manned camera (police van on lay by), which was approximately 25m after a long national speed limit section of road (single carriageway 60mph).
I dont dispute I was speeding and hope I am offered a speed awareness course. However for my own driving improvement and knowledge, what is the law / rule on time to slow down? Do you get an opportunity to reduce from 60 to 30 after the sign or are you expected to reach 30mph by the sign by slamming on your brakes (obviously this is dangerous and not advised). |
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Wed, 14 Aug 2019 - 14:48
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Wed, 14 Aug 2019 - 14:58
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#2
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Member Group: Members Posts: 3,300 Joined: 17 Jun 2011 Member No.: 47,602 |
There is no "time to slow down". The 30 limit starts at the sign. It shouldn't be necessary to slam on the brakes - the signs should be visible from a reasonable distance.
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Wed, 14 Aug 2019 - 14:58
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#3
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Member Group: Members Posts: 56,198 Joined: 9 Sep 2003 From: Warwickshire Member No.: 317 |
You have to slow down by the start of the limit, there is no allowance after that point at all.
May be checking that the signage reflects where the limit starts, the signage informs you of the limit, of itself it doesn’t set the limit. -------------------- There is no such thing as a law abiding motorist, just those who have been scammed and those yet to be scammed!
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Wed, 14 Aug 2019 - 15:30
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#4
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Member Group: Members Posts: 502 Joined: 11 May 2014 From: Scotland. Member No.: 70,553 |
Do you get an opportunity to reduce from 60 to 30 after the sign or are you expected to reach 30mph by the sign by slamming on your brakes (obviously this is dangerous and not advised). The 30mph limit starts at the sign, so if you are doing over 30mph after you pass the sign you are speeding. Rather than slam on the brakes and create a dangerous situation like you have suggested, you could slow down, gently and gradually when the sign is in sign, so by the time you pass it you're not speeding and not creating a dangerous situation either by "slamming on the brakes" -------------------- Patience is something you admire in the driver behind you, but not in one ahead. |
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Wed, 14 Aug 2019 - 16:52
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#5
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Member Group: Members Posts: 38,006 Joined: 3 Dec 2010 Member No.: 42,618 |
Do you get an opportunity to reduce from 60 to 30 after the sign or are you expected to reach 30mph by the sign by slamming on your brakes (obviously this is dangerous and not advised). As others have said, you have an opportunity to reduce from 60 to 30 before you pass the sign. -------------------- If you would like assistance with a penalty charge notice, please post a thread on https://www.ftla.uk/index.php
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Wed, 14 Aug 2019 - 20:39
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#6
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Member Group: Members Posts: 29 Joined: 26 Aug 2011 Member No.: 49,245 |
So obviously slowing down in advance of the sign is the answer and clearly I was joking about slamming on the brakes.
However as I implied in my message this is not consistent for all drivers - with varying ages and eye sights, varying knowledge of areas and varying reductions of speed (ie 40 to 30 or 50 to 30 etc), size of the sign all these different factors can affect the speed at which you can reduce to the limit implied. I dont know if anyone has done the maths on how long it takes to reasonably decelerate from 60 to 30 mph (again more factors at play ie braking efficiency, road surface, weather conditions, visibility, etc etc) but I think its quite possibly unreasonable to expect a 30mph drop in speed from 60 in a space of 50m (considering the min legal reading limit is 20m) This post has been edited by bluestreak56: Wed, 14 Aug 2019 - 20:40 |
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Wed, 14 Aug 2019 - 21:05
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#7
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Member Group: Members Posts: 3,300 Joined: 17 Jun 2011 Member No.: 47,602 |
I dont know if anyone has done the maths on how long it takes to reasonably decelerate from 60 to 30 mph (again more factors at play ie braking efficiency, road surface, weather conditions, visibility, etc etc) but I think its quite possibly unreasonable to expect a 30mph drop in speed from 60 in a space of 50m (considering the min legal reading limit is 20m) The "the min legal reading limit is 20m" for a number plate with characters 79mm in height. This has no relevance to a 30mph speed limit sign, which is at least 300mm in diameter! |
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Wed, 14 Aug 2019 - 21:25
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#8
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Member Group: Members Posts: 41,506 Joined: 25 Aug 2011 From: Planet Earth Member No.: 49,223 |
The previous TSGRD had minimum visibility distances for changes in speed limits, including 60 to 30. That was dropped in 2016 and as long as the limit is appropriately conveyed is sufficient.
Frankly it is highly unlikely that the 30mph terminal signs do not give reasonable distance to slow before passing the signs. But if they are then you always have the option to try and convince the court but will likely be a costly day out. -------------------- RK=Registered Keeper, OP=Original Poster (You!), CoFP=Conditional Offer of Fixed Penalty, NtK=Notice to Keeper, NtD=Notice to Driver
PoFA=Protection of Freedoms Act, SAC=Safety Awareness Course, NIP=Notice of Intended Prosecution, ADR=Alternative Dispute Resolution PPC=Private Parking Company, LBCCC=Letter Before County Court Claim, PII=Personally Identifiable Information, SAR=Subject Access Request Private Parking - remember, they just want your money and will say almost anything to get it. |
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Wed, 14 Aug 2019 - 21:25
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#9
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Member Group: Members Posts: 38,006 Joined: 3 Dec 2010 Member No.: 42,618 |
I dont know if anyone has done the maths on how long it takes to reasonably decelerate from 60 to 30 mph (again more factors at play ie braking efficiency, road surface, weather conditions, visibility, etc etc) but I think its quite possibly unreasonable to expect a 30mph drop in speed from 60 in a space of 50m (considering the min legal reading limit is 20m) The "the min legal reading limit is 20m" for a number plate with characters 79mm in height. This has no relevance to a 30mph speed limit sign, which is at least 300mm in diameter! Quite, and page 72 of the Traffic Signs Manual https://assets.publishing.service.gov.uk/go...-chapter-03.pdf conveniently has a table which indicates the minimum size for a terminal sign on a 60 mph road is 750 mm, or 900 mm if the road is over 10 metres wide. -------------------- If you would like assistance with a penalty charge notice, please post a thread on https://www.ftla.uk/index.php
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Wed, 14 Aug 2019 - 21:29
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#10
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Member Group: Members Posts: 4,746 Joined: 29 Oct 2008 Member No.: 23,623 |
I dont know if anyone has done the maths on how long it takes to reasonably decelerate from 60 to 30 mph (again more factors at play ie braking efficiency, road surface, weather conditions, visibility, etc etc) but I think its quite possibly unreasonable to expect a 30mph drop in speed from 60 in a space of 50m (considering the min legal reading limit is 20m) The stopping distance from 60mph to a standstill is given as 73m. The "thinking distance" is 18m. I'm quite sure you can shed 30mph in 32m. . On a straight road I would imagine a speed limit sign is visible from at least 150m. Even if you could not read the figures, a red circular sign should be sufficient to let you know you may need to slow down. All this, of course, assumes you are travelling at the full 60mph. If you are familiar with the area you will probably be aware of the upcoming 30mph limit. If you are not you might perhaps have been travelling slightly slower as you did not know what was round the next bend. Good luck if you want to defend the charge on the basis that you were not given sufficient notice to slow down. Personally I'd find another angle. This post has been edited by NewJudge: Wed, 14 Aug 2019 - 21:31 |
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Wed, 14 Aug 2019 - 22:10
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#11
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Member Group: Members Posts: 1,864 Joined: 2 Aug 2016 Member No.: 86,040 |
Surely the code stopping distances are for "slamming on the brakes"?.
In any event the stopping distance quoted by them at 73m and the braking distance from 30 of 14m would imply 59m for 60-30. I see plenty of limits where the terminal signs don't seem to have that level of visibiliy. But, as you say, that does raise other questions. On some roads here in somerset they have placed green or black terminal like sounds with a yellow countdown as advance warning which seems sensible to me. |
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Wed, 14 Aug 2019 - 23:11
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#12
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Member Group: Members Posts: 452 Joined: 25 Mar 2009 Member No.: 27,300 |
The Highway Code "stopping distances" are the "stopping distances" from the quoted speeds of a Ford Anglia (which was equipped with drum brakes) .
You can do your own maths with Newton's Equations (where "a" might equal -0.9 [so 0.9g deceleration] with modern disc brakes and a dry road surface) and calculate far shorter stopping distances from a given speed than the figures you post - but said calculated figures can be actually reflective of real life driving in extremis in a recent car and not a Ford Anglia . |
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Thu, 15 Aug 2019 - 04:45
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#13
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Member Group: Members Posts: 56,198 Joined: 9 Sep 2003 From: Warwickshire Member No.: 317 |
The stopping distance from 60mph to a standstill is given as 73m. The "thinking distance" is 18m. I'm quite sure you can shed 30mph in 32m. . Well you just proved otherwise.... If you can stop from 60 in 73m with a median speed of 30mph, slowing form 60 to 30 with a median speed of 45mph I will require circa 50% more than half that distance. Car brakes shed speed per time unit not time per distance unit. -------------------- There is no such thing as a law abiding motorist, just those who have been scammed and those yet to be scammed!
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Thu, 15 Aug 2019 - 05:25
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#14
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Member Group: Members Posts: 601 Joined: 7 May 2019 Member No.: 103,734 |
So obviously slowing down in advance of the sign is the answer and clearly I was joking about slamming on the brakes. However as I implied in my message this is not consistent for all drivers - with varying ages and eye sights, varying knowledge of areas and varying reductions of speed (ie 40 to 30 or 50 to 30 etc), size of the sign all these different factors can affect the speed at which you can reduce to the limit implied. I dont know if anyone has done the maths on how long it takes to reasonably decelerate from 60 to 30 mph (again more factors at play ie braking efficiency, road surface, weather conditions, visibility, etc etc) but I think its quite possibly unreasonable to expect a 30mph drop in speed from 60 in a space of 50m (considering the min legal reading limit is 20m) If you can’t see the signs in sufficient distance then it is likely you would be driving without adequate eyesight. Ignore the acceleration calculations as it is easily possible to reduce speed to 30mph from 60mph if you look for a sign and want to reduce speed...or indeed you are not mistaken and think the first half-mile of a speed limit is some form of deceleration buffer zone, as you did. |
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Thu, 15 Aug 2019 - 13:10
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#15
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Member Group: Members Posts: 4,746 Joined: 29 Oct 2008 Member No.: 23,623 |
Well you just proved otherwise.... If you can stop from 60 in 73m with a median speed of 30mph, slowing form 60 to 30 with a median speed of 45mph I will require circa 50% more than half that distance. Car brakes shed speed per time unit not time per distance unit. Except that the "thinking distance" will be the same whether braking from 60 to zero or 60 to 30. The actual braking distance (from 60 to zero according to the HC) is 55m. So using your calculation the braking distance from 60 to 30 is about 40m. So my estimate is a little adrift but I fear we are veering off into academia. I cannot imagine any "30" terminal sign marking the end of a single carriageway NSL (60mph) stretch having a clear visibility distance of only 50m (the length of five buses). The traffic Signs manual prescribes a minimum visibility distance of 115m. Only if the particular road exhibits an "85th percentile" speed of 50mph can this be reduced to 75m. That's why I suggest the OP is perhaps clutching at a particularly flimsy straw. I must say I've never encountered a situation where i have had to brake fiercely to get down to a lower limit. A gentle touch, maybe, but that's all. This post has been edited by NewJudge: Thu, 15 Aug 2019 - 13:12 |
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Thu, 15 Aug 2019 - 13:22
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#16
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Member Group: Members Posts: 56,198 Joined: 9 Sep 2003 From: Warwickshire Member No.: 317 |
I agree it was just academic, as you say I've never seen a 30 limit with that short of a visibility to the terminal signs.
-------------------- There is no such thing as a law abiding motorist, just those who have been scammed and those yet to be scammed!
S172's Rookies 1-0 Kent Council PCN's Rookies 1-0 Warwick Rookies 1-0 Birmingham PPC PCN's Rookies 10-0 PPC's |
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Thu, 15 Aug 2019 - 15:02
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#17
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Member Group: Members Posts: 28 Joined: 6 Dec 2017 Member No.: 95,428 |
Slowing down from 60mph (26m/s) to 30mph (13m/s) with a deceleration of .25g (2.5 m/s2) - which is fairly normal, gentle braking, covers a distance of almost exactly 100m. Heavier braking obviously reduces the distance travelled; if you jam the brakes on (7.5 m/s2) then the stopping distance is only 33m. This doesn't include thinking time, skidding etc etc but is a fairly good guide to what you might expect.
So long as the speed limit sign is visible from more than 100m away (and the vast majority are) then slowing down sufficiently is straightforward - engine braking plus a dab on the brakes (if needed) should do the trick. |
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Thu, 15 Aug 2019 - 15:44
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#18
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Member Group: Members Posts: 4,126 Joined: 31 Jan 2018 Member No.: 96,238 |
The priority is to get hold of the Traffic Order and find out exactly where the speed limit starts
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Thu, 15 Aug 2019 - 17:06
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#19
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Member Group: Members Posts: 56,198 Joined: 9 Sep 2003 From: Warwickshire Member No.: 317 |
Unless it’s already set by the end of a restricted road (street lighting every 183m or less)
A Google street view link or completed NIP wizard would help here. This post has been edited by The Rookie: Thu, 15 Aug 2019 - 17:07 -------------------- There is no such thing as a law abiding motorist, just those who have been scammed and those yet to be scammed!
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Thu, 15 Aug 2019 - 18:18
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#20
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Member Group: Members Posts: 38,006 Joined: 3 Dec 2010 Member No.: 42,618 |
Unless it’s already set by the end of a restricted road (street lighting every 183m or less) A Google street view link or completed NIP wizard would help here. On a restricted road, the limit starts at the first street lighting column. Many traffic authorities put terminal 30 mph signs (even though they're not legally required) but they neglect to make a TRO to cover the distance between the terminal sign and the first street lighting column. Therefore if the offence was detected after the terminal sign but before the first street light, it's worth checking if a TRO exists. -------------------- If you would like assistance with a penalty charge notice, please post a thread on https://www.ftla.uk/index.php
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