Reversed restrictions

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ais523
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Reversed restrictions

Post by ais523 »

"Maximum speed limit" signs are all over the road network. The opposite, a "minimum speed limit", is much rarer – drivers are taught what it looks like for their driving test, but many drivers will never actually see one.

Similarly, it's quite common for low bridges to provide a maximum height restriction for vehicles which want to go under them. The reverse seemed unlikely, so I was quite surprised to discover a minimum height restriction in Huntingdon – normal-sized vehicles can't go that way, with the route being limited to tall vehicles only. (The situation seems to be related to a CGSJ without much headroom – it's safest for most vehicles to use the junction in a grade-separated way, but tall vehicles can't do that to turn right, so they have to turn left and U-turn across the central reservation. The U-turn lane is presumably limited to tall vehicles because short vehicles have a safer alternative. Tall vehicles wouldn't otherwise have a safe escape route at all – a second low bridge means that they can't reach the next junction going left, so they couldn't turn round at the next junction, and they can't go straight on for the same reason that they can't turn right, so the special case is necessary.)

Are there other examples of a restriction being reversed from the usual sense? Even minimum speed limits are rare, and it'd be interesting to have a list – our wiki article Regulatory Sign/Minimum Speed is sorely lacking in details. Other minimum height limits, or, e.g., minimum weight limits, seem like they must be even rarer than minimum speed limits.
Last edited by ais523 on Wed Jun 22, 2022 08:10, edited 1 time in total.

From the SABRE Wiki: Regulatory Sign/Minimum Speed :


This sign means vehicles must not travel under the speed limit shown unless it is unsafe to do so.


This is a relatively new sign, and has no pre-Worboys equivalent.

The Scottish Roads Archive have a photo of the southern approach to the Clyde Tunnel from March 1964 showing two signs stating "Minimum 8mph". It pre-dates the erection of the first Worboys signs by around 6 months. They have suggested the signage was perhaps unique to the tunnel at

... Read More
Al__S
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Re: Reversed restrictions

Post by Al__S »

this particular one is curious- as it wasn't just for the junction, but more importantly for the A14 viaduct. A lot of signage given that tall vehicles would have been fairly rare, due to the road only accessing the hospital and a hosing estate.

The route to Huntingdon would have involved going out to Brampton, then onto the A14, A141 and in on Stukely Road.

I use the past tense here as the viaduct is no-more! The signs may still be in place for the junction though
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Re: Reversed restrictions

Post by Steven »

The A45 viaducts at Northampton have a really strange "no slow vehicles" worded restriction, with a plate underneath that reads "vehicles not able to exceed 25mph". It's not a minimum speed per se as you're not prohibited from driving that slowly, just that you must be physically able to.
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Alderpoint
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Re: Reversed restrictions

Post by Alderpoint »

Steven wrote: Wed Jun 22, 2022 08:27 The A45 viaducts at Northampton have a really strange "no slow vehicles" worded restriction, with a plate underneath that reads "vehicles not able to exceed 25mph". It's not a minimum speed per se as you're not prohibited from driving that slowly, just that you must be physically able to.
The blue roundall minimum speed limit sign has the proviso "unless it is impracticable or unsafe to comply" - which is pretty obvious really.....
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Alderpoint
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Re: Reversed restrictions

Post by Alderpoint »

Al__S wrote: Wed Jun 22, 2022 06:35 this particular one is curious- as it wasn't just for the junction, but more importantly for the A14 viaduct. A lot of signage given that tall vehicles would have been fairly rare, due to the road only accessing the hospital and a hosing estate.
And Hinchingbrook School, the police station, fire service HQ (how tall is a large fire engine?),...
I use the past tense here as the viaduct is no-more! The signs may still be in place for the junction though
Also now high vehicles can escape up the new Views Common Road.
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jervi
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Re: Reversed restrictions

Post by jervi »

ais523 wrote: Wed Jun 22, 2022 04:35 Are there other examples of a restriction being reversed from the usual sense? Even minimum speed limits are rare, and it'd be interesting to have a list – our wiki article Regulatory Sign/Minimum Speed is sorely lacking in details. Other minimum height limits, or, e.g., minimum weight limits, seem like they must be even rarer than minimum speed limits.
I've seen another no motor vehicles sign except vehicles over xx m. It was somewhere near Mansfield at a railway bridge providing a u-turning area, I think I've shared it on here before somewhere, but I cannot remember where it is, other than I think it was near Mansfield.

https://www.google.co.uk/maps/@51.31246 ... 384!8i8192
Its not exactly what you are looking for, but some places allow goods vehicles over a certain weight to use bus lanes.

From the SABRE Wiki: Regulatory Sign/Minimum Speed :


This sign means vehicles must not travel under the speed limit shown unless it is unsafe to do so.


This is a relatively new sign, and has no pre-Worboys equivalent.

The Scottish Roads Archive have a photo of the southern approach to the Clyde Tunnel from March 1964 showing two signs stating "Minimum 8mph". It pre-dates the erection of the first Worboys signs by around 6 months. They have suggested the signage was perhaps unique to the tunnel at

... Read More
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KeithW
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Re: Reversed restrictions

Post by KeithW »

Alderpoint wrote: Wed Jun 22, 2022 09:47 And Hinchingbrook School, the police station, fire service HQ (how tall is a large fire engine?),...
About 3.4 metres, in Huntingdon they have to fit in here.
https://www.google.co.uk/maps/@52.33100 ... 8192?hl=en
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solocle
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Re: Reversed restrictions

Post by solocle »

jervi wrote: Wed Jun 22, 2022 10:38
ais523 wrote: Wed Jun 22, 2022 04:35 Are there other examples of a restriction being reversed from the usual sense? Even minimum speed limits are rare, and it'd be interesting to have a list – our wiki article Regulatory Sign/Minimum Speed is sorely lacking in details. Other minimum height limits, or, e.g., minimum weight limits, seem like they must be even rarer than minimum speed limits.
I've seen another no motor vehicles sign except vehicles over xx m. It was somewhere near Mansfield at a railway bridge providing a u-turning area, I think I've shared it on here before somewhere, but I cannot remember where it is, other than I think it was near Mansfield.

https://www.google.co.uk/maps/@51.31246 ... 384!8i8192
Its not exactly what you are looking for, but some places allow goods vehicles over a certain weight to use bus lanes.
Also the A30 through Camberley - Here

From the SABRE Wiki: Regulatory Sign/Minimum Speed :


This sign means vehicles must not travel under the speed limit shown unless it is unsafe to do so.


This is a relatively new sign, and has no pre-Worboys equivalent.

The Scottish Roads Archive have a photo of the southern approach to the Clyde Tunnel from March 1964 showing two signs stating "Minimum 8mph". It pre-dates the erection of the first Worboys signs by around 6 months. They have suggested the signage was perhaps unique to the tunnel at

... Read More
WHBM
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Re: Reversed restrictions

Post by WHBM »

Steven wrote: Wed Jun 22, 2022 08:27 The A45 viaducts at Northampton have a really strange "no slow vehicles" worded restriction, with a plate underneath that reads "vehicles not able to exceed 25mph". It's not a minimum speed per se as you're not prohibited from driving that slowly, just that you must be physically able to.
Taken from the US standard signage of this, which prohibits "Vehicles Incapable of 40 mph" etc.
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Mapper89062
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Re: Reversed restrictions

Post by Mapper89062 »

There's one in Bury St Edmunds:
No entry except vehicles over 25 feet long
This one is because the parallel route to avoid this one-way section of the road is too tight and narrow for longer vehicles.

Off-topic, but why is the junction in Huntingdon grade separated in the first place? It's only a local junction, and is too close to the urban area in Huntingdon to be useful in providing a freeflowing route for the B1514.
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Skipsy
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Re: Reversed restrictions

Post by Skipsy »

I think this one relates to the topic since it seems reversed to what you would expect the sign to say, as most vehicles are excepted. They even painted the arrows to be straight only as if the majority of traffic would not be able to turn left here.
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Re: Reversed restrictions

Post by SteelCamel »

Skipsy wrote: Thu Jun 23, 2022 20:50 I think this one relates to the topic since it seems reversed to what you would expect the sign to say, as most vehicles are excepted. They even painted the arrows to be straight only as if the majority of traffic would not be able to turn left here.
There's the same restriction in Inverness. Though it seems it was changed in about 2019 from "30 cwts" to "7.5 tonnes".
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Re: Reversed restrictions

Post by Paul7755 »

Al__S wrote: Wed Jun 22, 2022 06:35 …A lot of signage given that tall vehicles would have been fairly rare, due to the road only accessing the hospital and a hosing estate.
Sorry, but I just have to mention that that typo conjured up an area filled with nothing but fire stations… :D :shock:
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Re: Reversed restrictions

Post by Vierwielen »

Steven wrote: Wed Jun 22, 2022 08:27 The A45 viaducts at Northampton have a really strange "no slow vehicles" worded restriction, with a plate underneath that reads "vehicles not able to exceed 25mph". It's not a minimum speed per se as you're not prohibited from driving that slowly, just that you must be physically able to.
This poses a few interesting questions. Would a Tour de France cyclist be permitted to use this road on their racing bikes. They could probably make 25 mph on the flat, but what about up hills?

The Vienna Convention has a sign for a minimum speed limt, but the text of the convention has nothing that would apply in this case. Many British signs tend to get rather verbose (worse in Wales), whch means that drivers whose mother tongue is not English (or Welsh in Wales) might not have enough time to read and to digest the information on the sign. That is the beauty of the Vienna Convention - road signs are pretty international.
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Re: Reversed restrictions

Post by B1040 »

Mapper89062 wrote: Wed Jun 22, 2022 16:46
Off-topic, but why is the junction in Huntingdon grade separated in the first place? It's only a local junction, and is too close to the urban area in Huntingdon to be useful in providing a freeflowing route for the B1514.
Used to be the main A604 from Huntingdon to Kettering. I guess it was to avoid right turning traffic for the school, hospital and police headquarters clogging the road.
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jervi
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Re: Reversed restrictions

Post by jervi »

Vierwielen wrote: Fri Jun 24, 2022 21:51
Steven wrote: Wed Jun 22, 2022 08:27 The A45 viaducts at Northampton have a really strange "no slow vehicles" worded restriction, with a plate underneath that reads "vehicles not able to exceed 25mph". It's not a minimum speed per se as you're not prohibited from driving that slowly, just that you must be physically able to.
This poses a few interesting questions. Would a Tour de France cyclist be permitted to use this road on their racing bikes. They could probably make 25 mph on the flat, but what about up hills?

The Vienna Convention has a sign for a minimum speed limt, but the text of the convention has nothing that would apply in this case. Many British signs tend to get rather verbose (worse in Wales), whch means that drivers whose mother tongue is not English (or Welsh in Wales) might not have enough time to read and to digest the information on the sign. That is the beauty of the Vienna Convention - road signs are pretty international.
So taking it at face value. A "slow vehicle" as far as I am aware is only defined at level crossings. That being a vehicle which does not exceed 5mph.

So the No Slow Vehicle Sign, despite it being a double negative I'd say means nothing that travels at below 5mph.
The supplement sign of "Vehicles not able to exceed 25 mph" I'd read as long as your vehicle is able to travel in excess of 25mph, then it is allowed. So really any vehicle can travel at 25mph if you are going down hill. Doesn't say it has to maintain a speed no less than 25 mph.
So a person on a skateboard I'd say is still fine, as long as you can prove you are able to 25 mph on it.
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Re: Reversed restrictions

Post by WHBM »

Savoy Court in London, where you drive on the right. Even the traffic signal is set up on the right.

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Re: Reversed restrictions

Post by FosseWay »

Vierwielen wrote: Fri Jun 24, 2022 21:51
Steven wrote: Wed Jun 22, 2022 08:27 The A45 viaducts at Northampton have a really strange "no slow vehicles" worded restriction, with a plate underneath that reads "vehicles not able to exceed 25mph". It's not a minimum speed per se as you're not prohibited from driving that slowly, just that you must be physically able to.
This poses a few interesting questions. Would a Tour de France cyclist be permitted to use this road on their racing bikes. They could probably make 25 mph on the flat, but what about up hills?
Never mind Tour de France cyclists, I'm perfectly capable of exceeding 25 mph. I think the fastest I've recorded is 70 km/h. Now whether I'd be able to exceed 25 just there is another question, but the signage doesn't say that is a requirement.
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solocle
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Re: Reversed restrictions

Post by solocle »

FosseWay wrote: Sat Jun 25, 2022 12:48
Vierwielen wrote: Fri Jun 24, 2022 21:51
Steven wrote: Wed Jun 22, 2022 08:27 The A45 viaducts at Northampton have a really strange "no slow vehicles" worded restriction, with a plate underneath that reads "vehicles not able to exceed 25mph". It's not a minimum speed per se as you're not prohibited from driving that slowly, just that you must be physically able to.
This poses a few interesting questions. Would a Tour de France cyclist be permitted to use this road on their racing bikes. They could probably make 25 mph on the flat, but what about up hills?
Never mind Tour de France cyclists, I'm perfectly capable of exceeding 25 mph. I think the fastest I've recorded is 70 km/h. Now whether I'd be able to exceed 25 just there is another question, but the signage doesn't say that is a requirement.
I mean, the fastest I've recorded is 92 km/h, but somewhat irrelevant. It's the same restriction as for Class I motorway traffic, where it's clearly defined that it applies on flat and level ground. I think it's safe to conclude the same for this.

Which still allows me on my bike, as I can sprint to 30 mph. :laugh: In fact, with a lead out off a bus, I once clocked 35. As opposed to outright drafting of a motor vehicle, where I once got 48 mph on the Oxford Ring Road. :o

By no means a maximum, but a fairly easy to look out 27 mph in the middle of a 10 mile TT, m'laud.
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the cheesecake man
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Re: Reversed restrictions

Post by the cheesecake man »

This has been mention on other threads but St Ives old bridge has a 3 tonne minimum weight.
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