Road signage - help with obscure questions please

[Blackbird]

On open roads where the safe cornering speed is deemed to be less than 100 km/hr, it's normal to see an advisory sign stating the recommended safe speed.

1. Who is responsible for determining whether a corner should be marked or not (e.g. Transit, local bodies etc) and what criteria are used? Are there any formal statutes?

2. If an obscured corner is not marked, but safe cornering speed is clearly below 100 km, I presume that the onus is still on the driver/rider to negotiate it in a safe manner even though there is no advisory limit?

Cheers

Geoff

[klingon]

On open roads where the safe cornering speed is deemed to be less than 100 km/hr, it's normal to see an advisory sign stating the recommended safe speed.

1. Who is responsible for determining whether a corner should be marked or not (e.g. Transit, local bodies etc) and what criteria are used? Are there any formal statutes?

It depends on the road. Designated state highways are the responsibility of Transit and other roads are the local body's responsibility. There are exceptions - like every highway has to have another route available and sometimes Transit and councils will co-operate to make sure it's maintained. I don't know what statutes cover the signage - they seem to vary a lot in different parts of the country.



2. If an obscured corner is not marked, but safe cornering speed is clearly below 100 km, I presume that the onus is still on the driver/rider to negotiate it in a safe manner even though there is no advisory limit?


Absolutely true. It's the driver's/rider's responsibility to keep their vehicle under control even if they're going well below the speed limit. Had a friend charged with dangerous driving causing injury a few years ago when she lost control of her vehicle while doing 80 in a 100kph zone. The only person she injured was herself. I think the real problem was that she argued with the nice policeman. :innocent:

If you think a particular road needs signage, email the council or transit for a start. Make sure you've done your homework (records of accidents or near misses etc) and put a dispassionate and well reasoned case.

[Ixion]

This may be helpful
http://www.ipenz.org.nz/ipenztg/ipenztg_cd/cd/2002_pdf/33_Koorey_Advisory.pdf

My understanding (though based on I know not what), is that there is no statutory requirement about advisory signs. That is, there is no law that says anyone MUST post one in any specific circumstances. they are advisory. Like the ones show the shape of corners, or the "Wiggly road ahead" ones. If the authority for the road thinks a corner could do with one they stick one up. Or not, as the case may be.Obviously not every bend can have a sign, it would become absurd. But there is a standard method for determining the advised speed if they do put one up.

Whether there is a sign or not, it is the responsibility of the driver to drive at a speed that is safe for the corner in all circumstances.

[Drum]

I used to work for an engineering consultant to Transit NZ and we used to run the tests and determine the advisory speeds. Transit posts all the sings on the State Highways. The Local Authorities look after the rest of the roads.

To conduct the test you drive around the corner three times or more in a car fitted with a special meter and measure the sideways G-force (averaging the three runs). Then cross referencing this against the approach speed to the curve you determine the advisory speed. For a new road the approach speed is determined by design calculations. For an existing road a speed survey is undertaken.

As far as statutory requirements - it's not legally required to post the advisory speed - a driver must determine the correct speed to negotiate a given curve - however they are posted because Transit and Local Authorities have a genuine desire to reduce crash rates.

[Ixion]

I used to work for an engineering consultant to Transit NZ and we used to run the tests and determine the advisory speeds. ,,

AH-HA. So it's YOUR fault. Henceforth everytime someone crashs on a corner we can blame you for posting a speed that was too high - or, at any rate, was too high once the standard "assume it's in mph not kph" adjustment is applied.

[jahrasti]

On open roads where the safe cornering speed is deemed to be less than 100 km/hr, it's normal to see an advisory sign stating the recommended safe speed.

1. Who is responsible for determining whether a corner should be marked or not (e.g. Transit, local bodies etc) and what criteria are used? Are there any formal statutes?

2. If an obscured corner is not marked, but safe cornering speed is clearly below 100 km, I presume that the onus is still on the driver/rider to negotiate it in a safe manner even though there is no advisory limit?

Cheers

Geoff


In regards to the speed signs, something that is used is a ballbank (not a ballbag )
This is a ball bearing on a scale and the corner is taken from both sides and from a graph a speed is found, this speed can differ depending on which side you take it from.

OR

You could see how much money you have left in the budget place some up willy nilly to keep your contactual obligations.( this is a p/t ):innocent:

[Ixion]

Incidentally , it is no defense, having crashed, to argue that it is the fault of the sign people, on the grounds that the previous 20 corners were signed with advisory speeds rediculously below the real world speed for the corner, whereas THIS skank of a corner was signed with an advisory speed that really WAS the correct speed for the corner. And you, not knowing that , applied that "double and some more" adjustment that worked for the last twenty corners.

I know a few like that.

[Da Bird]

I got told the other day that advisory speeds were supposed to be the speed at which a truck could safely get around the corner on a wet road. Not sure how true that is but sounds plausible. Obviously it is up to the individual to ensure they do actually get around corners.

BC

[Blackbird]

Really appreciate the collected wisdom everyone, that has helped no end. What a great bunch of people you are:rockon:

There may be a follow-up later.

Cheers

Geoff

[Drum]

The speed advisory is generally around 15 - 20 km/h lower than the maximum speed at which a car can 'safely' negotiate the corner.

The speed advisory plates don't mean much for a motorcycle.

[Motu]

Close. It is a driver in a family saloon car negotiating the corner in wet conditions.. So it is lowest common denominator stuff.. much like the speed limits.

So posted corner speeds have increased over the years then,since they stopped using an HQ Holden on cross ply tyres?

[The Pastor]

2. If an obscured corner is not marked, but safe cornering speed is clearly below 100 km, I presume that the onus is still on the driver/rider to negotiate it in a safe manner even though there is no advisory limit?


Think of it this way, IF you crash on a corner is it the sgins fault or yours?

I mean what the hell are you typing? IS there any other answer to that question? The onus isnt on the driver because he isnt the one in charge of the car..... Pointless dirivel. What ever your smoking - I want some.

[Motu]

Put a 20 year old in an HQ on crossplies on a wet road and find out.

I know what my prediction is.....

[Crisis management]

The speed advisory is generally around 15 - 20 km/h lower than the maximum speed at which a car can 'safely' negotiate the corner.

The speed advisory plates don't mean much for a motorcycle.

I'm not sure about this one, I would have said a car (of reasonable quality) could always corner faster than a bike.....have the laws of physics been changed lately?

[Drum]

I'm not sure about this one, I would have said a car (of reasonable quality) could always corner faster than a bike.....have the laws of physics been changed lately?

No, I just mean that the tests are carried out using a car, and the speed advisory posted has nothing at all to do with bike physics or riding technique. Motorcycles and cars have different approach speeds and take a different line when cornering. Therefore the advisories are meaningless for bikes.

[Crisis management]

No, I just mean that the tests are carried out using a car, and the speed advisory posted has nothing at all to do with bike physics or riding technique. Motorcycles and cars have different approach speeds and take a different line when cornering. Therefore the advisories are meaningless for bikes.

Ok, I see what you mean, but surely if we were to apply the same rules to bike corner speed, ie. a safe, comfortable speed that the lowest denominator bike could negotiate the corner we would have the same result - a speed perceived by most as too slow?
I would argue that the advisory speeds are useful in that they do give you a bit of a hint, thats all they are supposed to do anyway.

[Hitcher]

And the approved measuring device for cornering speeds is a Parkinson's-afflicted Little Old Lady(TM), holding an egg in a spoon.

[Blackbird]

I tend to use the signs as an indicator to the degree of tightness, or degree of difficulty....not even concerned as to what the actual speed that is written on the sign.
Say its a 75.... that means basiclly full noise, that corner wont be a problem. 65..maybe roll off throttle before entering corner and get a vanishing point going. 55.. gear down, slightest touch on the brake, then wind throttle on once in the corner. right down to 25s or 15s when it is nearly a second gear, full brake on approach corner.

Completely agree. I tend to register a sign at the almost subconscious level that there's something to watch out for.

[KLOWN]

I'm not sure about this one, I would have said a car (of reasonable quality) could always corner faster than a bike.....have the laws of physics been changed lately?


there has been endless debates about this so we won't get into another one but in a bike you are able to "cut" the corner and stay on your side of the road because you don't take up the whole lane where as a car is forced to not take an ideal line (if you don't count the people who cross the white line) because they are much wider vehicles.

also since we are on the topic of laws of physics a great deal of how quickly you can go round a corner is to do with the "grip" of your tyres or the "friction coefficient" as its called and bike tyres may have less of the tyre on the road but they have a greater friction coefficient to counter act this

[klingon]

I tend to use the signs as an indicator to the degree of tightness, or degree of difficulty....not even concerned as to what the actual speed that is written on the sign.
Say its a 75.... that means basiclly full noise, that corner wont be a problem. 65..maybe roll off throttle before entering corner and get a vanishing point going. 55.. gear down, slightest touch on the brake, then wind throttle on once in the corner. right down to 25s or 15s when it is nearly a second gear, full brake on approach corner.

Yeah, the signs can be useful once you've worked out your own rule of thumb. In my little '89 corolla when fully loaded (the car, not me) I tend to go around unfamiliar corners about 15kph faster than the advisory, on condition the road is dry.

On a wet road, or when driving the Camry or the Audi, or when the loading is different, or on corners I'm familiar with, obviously it all changes.

And yes, I am a little old lady with an egg in a spoon

[paturoa]

Has anyone else noticed that all of the recommended speeds end in 5, i.e. 55 65, 75, etc.

The only exception I have seen (noticed?) where they end in zeros, i.e. 50, 60, 70 and that is on Scenic Drive in the Waitakeres.

Go figure...

[Blackbird]

Has anyone else noticed that all of the recommended speeds end in 5, i.e. 55 65, 75, etc.

The only exception I have seen (noticed?) where they end in zeros, i.e. 50, 60, 70 and that is on Scenic Drive in the Waitakeres.

Go figure...


A recommendation was made by some consultants in 1972 to round off advisory speeds to zeros (see Ixion's link in the post). The wheels of State grind exceedingly slow....

[Toaster]

"Advisory" means exactly that. No matter what any sign says, you are required to drive/ride with due care at all times and drive/ride to the conditions. If you screw up, you are in the poo-cart.

[Toaster]

I found that leaning over in the corners too close to the centreline created issues when meeting trucks coming the other way. Pays to take a conservative line sometimes!

[Drum]

Has anyone else noticed that all of the recommended speeds end in 5, i.e. 55 65, 75, etc.

The only exception I have seen (noticed?) where they end in zeros, i.e. 50, 60, 70 and that is on Scenic Drive in the Waitakeres.

Go figure...

That is the rule. Advisories end in a "5" while speed limits end in a "0". Supposed to stop confusion between the two. Where you see an advisory ending in a "0" then it is either very old, or was incorrectly installed.

[Drum]

"Advisory" means exactly that. No matter what any sign says, you are required to drive/ride with due care at all times and drive/ride to the conditions. If you screw up, you are in the poo-cart.

Exactly!!!

[paturoa]

That is the rule. Advisories end in a "5" while speed limits end in a "0". Supposed to stop confusion between the two. Where you see an advisory ending in a "0" then it is either very old, or was incorrectly installed.

They definitely end with zeros along scenic drive from the southern end. Some of them look very new too, but they maybe replacements.

[Hillbilly]

Here's a real obscure road sign: