Safe Speed Forums

I believe I have stumbled across something which could help safety and save lives.

When I was riding at the weekend on my motorbike I noticed the road I was using was surfaced with a new type of Tarmac which is black - jet black. I am seeing it used much more of late.

I know there have been recent improvements in road surfaces, both in adhesion and noise generation, but I think they have made, (are making), a big mistake with this!

With other types of road surface, which are a lighter gray or ash texture, you could easily see a wet patch or petrol/oil spill etc. But on this new type of surface it was simply impossible. There is virtually no contrast between the natural colour or when it is wet with 'something'.

A program I was watching just the other day, called Real Rescues, had a young woman who had skidded across the wrong side of the road because of a spillage and got involved in an accident which could have been much more serious. Although it wasn't mentioned on the program, together with my experience at the weekend it made me wonder if this could be part of the problem?

This new road surface is far more dangerous to us motorcyclists' of course. We are always looking for variations in the road conditions - our very lives' depend on it in fact.

So isn't it possible to keep the same good qualities but change the colour back to something which acts like litmus paper to us?

I have also wondered if it is more likely to overheat in the hotter weather, but maybe they have considered that?

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The views expressed in this post are personal opinions and do not necessarily represent the views of Safe Speed.
You will be branded a threat to society by going over a speed limit where it is safe to do so, and suffer the consequences of your actions in a way criminals do not, more so than someone who is a real threat to our society.

There were quite a few news articles about this new tarmac. Apparently when it is new it is silppery when dry!

I have experianced this my self when driving a pool car without anti lock brakes. I was only doing about 25 when someone pulled out on me. It just skids for ever!

I know you could say its my fault for just stabbing at the brake, but I drive anti lock brakes 99.99 % of the time. I did stop with less than a foot to spare.

I believe the top surface just melts and lubricates the skid.

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Speed limit sign radio interview. TV Snap Unhappy
“It has never been the rule in this country – I hope it never will be - that suspected criminal offences must automatically be the subject of prosecution” He added that there should be a prosecution: “wherever it appears that the offence or the circumstances of its commission is or are of such a character that a prosecution in respect thereof is required in the public interest”
This approach has been endorsed by Attorney General ever since 1951. CPS Code

Thanks Anton. I honestly think I'm onto something very bad here.

Oh, and ask any motorcyclist about melted tar on a very hot day if you want to see him wince.

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The views expressed in this post are personal opinions and do not necessarily represent the views of Safe Speed.
You will be branded a threat to society by going over a speed limit where it is safe to do so, and suffer the consequences of your actions in a way criminals do not, more so than someone who is a real threat to our society.

Just to add to the story I believe it is not to be used on roads over 40mph??

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Speed limit sign radio interview. TV Snap Unhappy
“It has never been the rule in this country – I hope it never will be - that suspected criminal offences must automatically be the subject of prosecution” He added that there should be a prosecution: “wherever it appears that the offence or the circumstances of its commission is or are of such a character that a prosecution in respect thereof is required in the public interest”
This approach has been endorsed by Attorney General ever since 1951. CPS Code

Not where I was I'm affraid. NSL over by Stratford on Avon.

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The views expressed in this post are personal opinions and do not necessarily represent the views of Safe Speed.
You will be branded a threat to society by going over a speed limit where it is safe to do so, and suffer the consequences of your actions in a way criminals do not, more so than someone who is a real threat to our society.

It's called stone mastic ashphalt. It is well known as being lethal when first laid. I think real story have already covered it. Some EU countries it is banned entirely. When they did my street with the grey version for weeks all you'd here was the sound of skidding cars as people braked normally and found they weren't slowing down.

I'd write to your local MP and complain about how dangerous it is and ask why the highways department are using a known dangerous road surface. The answer will be to save money which is always more important It is banned in Ireland I think for any road over 40mph.

I didn't know that. It worse than I thought then?

I really do feel very strongly about this and I think it's a disgrace that it hasn't been addressed by the authorities, or that it even got through in the first place. I would happily write to the council or MP but my past experiences of dealing with them isn't exactly favourable.

I don't have any evidence that it is more dangerous other than my 30+ years of riding and driving around the world. However, common sense tells me that it's bad not to be able to easily differentiate between a dry road and a road with something spread on its surface.

It's more likely that people will have to lose their lives by skidding across the road on this black stuff before anything is done, which of course will be blamed on excessive speed.

I feel like taking pictures of a before and after throwing water across the two types of surface to make my point to them.

At least it sounds like people here know exactly what I'm on about but what worries me is that this means they must be using this black surface across the whole country.

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The views expressed in this post are personal opinions and do not necessarily represent the views of Safe Speed.
You will be branded a threat to society by going over a speed limit where it is safe to do so, and suffer the consequences of your actions in a way criminals do not, more so than someone who is a real threat to our society.

I've driven on recently laid SMA and never noticed the problem.

However when I drive over certain bridges (example: Kessock bridge, just north of Inverness) I'm highly aware of low grip due to special hard wearing surfaces.

My awareness comes from steering feel and larger-than-usual slip angles. I'm sensitive to it, and mostly I go out of my way to choose vehicles that are sensitive to it. Even in the campervan I easily feel the low grip over the Kessock bridge.

Hence I'm confused. Are the reported problems with SMA real? Or theoretical? Or is SMA sometimes low grip?

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Paul Smith
Our scrap speed cameras petition got over 28,000 sigs
The Safe Speed campaign demands a return to intelligent road safety

From the few web searches I've done today this looks to me like another classic case of proceeding without full research again. (just like the cameras')

I can see you're right teabelly, about it not being used in Ireland.

http://news.bbc.co.uk/1/hi/programmes/f ... 278419.stm

"File On 4 found the same surfaces are banned in Ireland on some roads because of fears about poor grip.

The Department for Transport said just because roads require further investigation, "it doesn't necessarily mean they are unsafe".

SMA surfacing systems are widely used because they are said to last a long time, are quick to lay and give a smooth, quiet ride.

But police crash investigators have become concerned because, in certain conditions, some do not offer much grip for up to two years until they have bedded in. "


Of all the sites I have looked at not one mentions the very real danger of having a black surface and how it masks any spillage etc. Maybe because I'm also a biker I am more aware just how important this is but like I say, cars and HGVs too will be affected.

Surely this is an accident waiting to happen, probably already has many times but was logged as 'driver error'?

This is ridiculous! Unbelievable!!!

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The views expressed in this post are personal opinions and do not necessarily represent the views of Safe Speed.
You will be branded a threat to society by going over a speed limit where it is safe to do so, and suffer the consequences of your actions in a way criminals do not, more so than someone who is a real threat to our society.

If this stuff is only good for 40mph, maybe that’s why they’re lowering urban speed limits to 40mph, then nobody can make a claim if they have an accident, maybe the councils are keeping it quite.

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Useless laws weaken necessary laws.

Yes, that what happened! but I was ony doing 25

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Speed limit sign radio interview. TV Snap Unhappy
“It has never been the rule in this country – I hope it never will be - that suspected criminal offences must automatically be the subject of prosecution” He added that there should be a prosecution: “wherever it appears that the offence or the circumstances of its commission is or are of such a character that a prosecution in respect thereof is required in the public interest”
This approach has been endorsed by Attorney General ever since 1951. CPS Code

I can't believe what I'm reading here and on the web

Why isn't this headline news somewhere? How did they get away with it?

The gov rips me off to the tune of about £200 a year for road tax of which only a tiny bit actually goes towards the roads and, from web searches, I see councils' are bleating on about saving money and now make roads which are inferior and more dangerous than what the Romans built.

Heads should roll for this!

_________________
The views expressed in this post are personal opinions and do not necessarily represent the views of Safe Speed.
You will be branded a threat to society by going over a speed limit where it is safe to do so, and suffer the consequences of your actions in a way criminals do not, more so than someone who is a real threat to our society.

There have been a few headlines. SMA ultimately is a good road surface - smooth, quiet, grippy and durable. But there are persistant stories about low grip when first laid.

Some of it is scare, but probably some of it is real too. It's very hard indeed to know how big or how widespead the real problems are.

Let's not risk being hysterical with insufficient information. Such hysteria is far better left to our 'opponents'.

Now, seriously, how do we find a way forward? What science is there and how good is it? What grip levels have been actually measured, and how do they compare with other surfaces? How do different sections of new SMA differ in grip levels? Is there a wide variation? Is there a problem with some SMA application techniques?

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Paul Smith
Our scrap speed cameras petition got over 28,000 sigs
The Safe Speed campaign demands a return to intelligent road safety

Having laid SMA on a couple of roads, including a 40mph stretch of the A570, Ormskirk- Southport, ( Red Lion Bridge to Morris Dancers) slippery surface signs were installed, and Highway Engineer folklore says it's actually better in the wet than dry when first laid.

The chippings are mixed in and hence covered with the mastic (tar), so on the surface this is the material in contact with the tyres, it's hardwearing qualities mean it takes longer to wear off this surface and expose the chippings surface, other 'tars' wear off the chippings quicker, the surface will stay blacker for longer for the same reason.

I didn't design it, or specify it, I just had to lay it as contracted by the HA.

For bikes I reckon part worn in will be the most scary as across the width of the carriageway will be areas of varying grip.

fatboytim

I posted about SMA a while ago. After an article by a police officer who had tested it's dry grip levels and found them to be lacking.

There were also complaints from horse riders that the horses couldn't get a grip.

But my main argument was how do you tell wet from dry, (wet being: petrol/oil/water), on a jet black road? It's easy to spot on the older gray/ash coloured roads and you can see when they are drying out or sections and patches which are drier.

Regardless of whether it is or isn't better, which is important of course, it is still the wrong colour from a safety aspect. The obvious has been completely missed or ignored!

This is what prompted my original question but no-one seems to understand or care. Am I a lonely voice in the wilderness?

I'm desperate for understanding here

_________________
The views expressed in this post are personal opinions and do not necessarily represent the views of Safe Speed.
You will be branded a threat to society by going over a speed limit where it is safe to do so, and suffer the consequences of your actions in a way criminals do not, more so than someone who is a real threat to our society.

I hear what you are saying. I don't think you will win on that argument alone. We had white concrete motorways round here, the drainage was awfull. but they were cheap! You couldn't see if there was liquid on them either... apart from the spray!

There is somthing about sma like crossply tyres. Its not just the low grip , it is how it lets go. It is all or nothing.

Normal braking and cornering its nice and smoth and grippy. Stab your brakes and it runs away.

You might have to add your argument to the grip argument to win. but hey no one is listening to any one with any sense. Ask Paul!
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more resources
http://www.highwaysmaintenance.com/bitdiags.htm and links to trl reports on the stuff

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Speed limit sign radio interview. TV Snap Unhappy
“It has never been the rule in this country – I hope it never will be - that suspected criminal offences must automatically be the subject of prosecution” He added that there should be a prosecution: “wherever it appears that the offence or the circumstances of its commission is or are of such a character that a prosecution in respect thereof is required in the public interest”
This approach has been endorsed by Attorney General ever since 1951. CPS Code

From what I know about the frighteningly complex tyre/tarmac interface, I don't understand how such a characteristic could be possible.

In many simpler friction circumstances there's a clear divide between 'static' and 'dynamic' friction. But with tyres and tarmac it's always dynamic friction. There is always some slip (or at least there's always slip when anything at all interesting is happening (like cornering)).

Oh, wait a minute...



Typical friction characteristics: (a) dry asphalt; (b) wet asphalt; (c) gravel; and (d) packed snow.

We might be suggesting that we get a 'funny shape' 'a' curve. If it dropped far more steeply after the peak that would give the characteristics that both of us have described. I probably never have ventured beyond the peak...

Very interesting. I don't know what sets the past-peak slope. It's usually pretty reliable.

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Paul Smith
Our scrap speed cameras petition got over 28,000 sigs
The Safe Speed campaign demands a return to intelligent road safety

This stuf is fully coated chips that stay fully coated for up to two years rather than tar with dry chips poured on top leaving a dry clean gravel top surface.

If the contact pad of my tyre is 150mm wide and 100mm deep under normal braking.

But if the 1st 10mm melted under skid braking and lubricates the other 90mm of contact... I lose 90% of my braking

Also the normal driven path may regain its grip after 6 months. But off the driven line, where you probobly are skidding it will not be worn off.

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Speed limit sign radio interview. TV Snap Unhappy
“It has never been the rule in this country – I hope it never will be - that suspected criminal offences must automatically be the subject of prosecution” He added that there should be a prosecution: “wherever it appears that the offence or the circumstances of its commission is or are of such a character that a prosecution in respect thereof is required in the public interest”
This approach has been endorsed by Attorney General ever since 1951. CPS Code

But there's always cold tarmac being fed in at the front, and the exposure of any particular particle of tarmac to a heating effect is very brief as you slide on.

It'd be hard to believe that enough temperature rise is present in the road surface to approach melting point.

At 60mph with a 4 inch contact patch, a particle of road suface only experiences the tyre for 3.8ms. (1/(60*1.46667*3))

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Paul Smith
Our scrap speed cameras petition got over 28,000 sigs
The Safe Speed campaign demands a return to intelligent road safety