Safe Speed Forums

Right, a dual carriageway to me was always a road with two lanes in either direction, but I do believe I am wrong... It just means a road with 2 seperate carriageways in either direction, so you can have one lane in either direction and it can still be a dual carriageway, as long as it has a central reservation? Is that right?

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Mike

Yes

Also, you can have two lanes in either direction, no central reservation and that is NOT a dual carriageway.

Question is, how long does the central reservation have to be. Does a traffic island mean that 2 metres of that road are now dualled, and thus become a 70 limit.

Thanks... Sorry I'm a bit silly It's just I saw a sign today for 'Dual Carriageway Ahead' and the road split, but the extra lane I always linked with a D/C never appeared, but I suppose that makes sense, as it is 2 carriageways, rather than 1...

On the other hand there's a bit of road near me which has a central reservation, 2 lanes either side, and I don't think there's any 'Dual Carriageway Ahead' sign there, although it's a restricted road so...

That also clarifies something about ANOTHER bit of road that I drive on sometimes... There's a stretch of road that was recently split into 2 lanes, but only one lane in either direction, and my dad was driving, he was doing 60 (this doesn't apply to me yet, being restricted) but there's a crawler lane, and he was going on, oh those people don't realise the limit here is only 60, yet if you apply the D/C description to it, it's 70, because there is a fairly substantial central reservation (5 or so metres).

Although, there's no sign on that road to say its a D/C, so... Does it have to have a D/C ahead or whatever sign?

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Mike

The idea is that the little bit of grass (which is all you need to qualify for dual carriageway status, don't even need a raised curb) somehow makes head-on collisions less likely and thus you can have an extra 10mph and still be safe.

AFAICT, you don't need kerbs or grass. According to http://www.opsi.gov.uk/si/si2002/20023113.htm,
and

So, if you have a strip of land between the carriageways upon which the traffic cannot go except in emergencies, you have a dual carriageway.

Now, the Highway Code, 109 says:
So, if you have an area of tarmac separating the opposite flows and that area of tarmac has unbroken white lines each side and chevron hatchings, that road is dual carriageway and by default a 70mph limit. However, if the hatchings are diagonal, it's not a dual carriageway (because the prohibition from that "reservation" is only advisory).

WRT whether a traffic island makes the short stretch of road it's in a dual carriageway - the answer is "no" because traffic islands are specifically excluded under the rules.

HTH,

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Will

The Highways Agency don't seem to agree, though.

When they first put 60 signs up on the S4 section of the A556 in Cheshire, there were NSL signs at the start of each central island, such as at the junction with the A5033, and 60 signs at the end of the island. This clearly indicates that for those short stretches the theoretical limit was 70.

Presumably they later got a speed limit order reducing those short sections to 60, and the extra signing was removed.

There is a distinct grey area between what is a traffic island and what is a dual carriageway - the A616 Stocksbridge Bypass has some quite lengthy central islands, although IIRC they are outside the scope of the SPECS cameras.

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"Show me someone who says that they have never exceeded a speed limit, and I'll show you a liar, or a menace." (Austin Williams - Director, Transport Research Group)

Any views expressed in this post are personal opinions and may not represent the views of Safe Speed

I always assumed to become an official DC it had to have the "DC ahead" blue sign at the start, and red "lanes merging" symbol at the end

The first one I was talking about is only about half a mile, if even that, it's just a stretch at a motorway junction. It has the blue D/C ahead and then a red triangle with an arrow in either direction to show that the 2 carriageways are merging...

It's sorta silly the way it happens, and what if they put scams on these stretches, due to bad signage, people are going to get caught for doing what they think is legal...

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Mike

I remember reading the laws quoted by willcove in a post somewhere, possibly PePiPoo, where there was a debait as to wether a road with double white lines down the middle was a dual carageway. As you are not allowed in to the middle, and the middle is land, it does seem to fit the description

But yeah, dual carageway = two carageways. Lanes are only advisory anyway. (Especially in London)

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Andrew.

IIRC, I was involved in that discussion - and it was me that suggested that double-white lines (DWL) might make the road dual carriageway. However, DWL do not a dual carriageway make because traffic is allowed to cross DWL in circumstances other than an emergency. For example, you can cross them if safe to do so to overtake other traffic that is moving at 10 mph or less. ISTR that was also when I learned the distiction between straight hatching and chevrons

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Will

There used to be a naughty one on the A5 east (NSL area). It is dual carriageway with central reservation but then one lane is blocked off by solid diagonal white lines just where the speed camera sits. EVERYONE who goes through there brakes.....60 or 70, who wants to take the risk. Don't know if it is still there.

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Speed camera policy Kills

Two of the three GATSOs in the Cleveland constabulary area are on the A177 at Thorpe Thewles on a section of dual carriageway that has been reduced from 2 lanes to 1 across a junction. The limit has been reduced to 60 mph and the signs clearly show this.

Although I cross at this junction regularly I realised an interesting anomaly on Saturday. When you leave the 30 mph restriction in Thorpe Thewles village, the sign shows 60 mph. When you leave the DC towards Wynyard on a single carriageway road you get an NSL derestriction sign which also means 60 mph, so why bother with this sign as less informed people might think the limit is now something other than 60, such as 70?

Think you're talking about the approach from the Higham on the hill junction toward the Royal Redgate Junction with the A444, only about a few hundred yards long, has a DC ahead sign , but as you say some prat tried to make it look like a single lane with hatching, meaning lots of braking for the camera , and a lot less attention for the impending junction , where cars still try and join with no real chance of doing so - to find the approaching traffic is still mesmerised by the "is it 60 or 70 " camera and fail to see them till the last minuet - a really clever way to cause ,rather than prevent accidents.

Suppose this shows the real reason for the camera - stop people overtaking and if they do make some money - if safety was the real reason ,this junction would be slowed down -- or if they were really that concerned with road safety - install an island( rant over)

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lets bring sanity back to speed limits.
Drivers are like donkeys -they respond best to a carrot, not a stick .Road safety experts are like Asses - best kept covered up ,or sat on