Safe Speed Forums

Safety?? New road-surfaces being used in some areas are cheaper and longer-lasting due to containing harder material. What no-one is mentioning is the fact that (like tyres) harder = less grip, and these surfaces increase your braking-distance by up to 30%. Apparantly councils are only obliged to display a 'slippery surfaces' warning sign at some (predetermined?) point of the road concerned. As a motorcyclist I e-mailed the AA, RAC and TRL about this, with stunning lack of response. How can anyone claim to give a monkey's about 'safety' whilst laying effective booby-traps? I joined this forum to try and get the message out. Chris.

Are you talking about SMA or something else?

We're certainly interested in anything that can be identified as a 'real' road safety issue. One big problem is that there's a great deal of rubbish talked, and even quite a bit of the science is rubbish.

We have learned that (almost) nothing in road safety is as simple as it might appear. Often a parameter that sounds as if it should be important is massively swamped by some other paramerter that almost passes unnoticed. There are many factors affecting (for example) braking distances, including gradient (up or down), weather, road surface contamination, type and condition of tyres, road surface type, design of vehicle, alertness of driver, skill of driver, nature of hazard (yes we do manage to stop shorter when we perceive that it is a 'real emergency') and so on. It's 'fairly likely' that the effects of all these parameters swamp the slightly poorer performance of the new surface materials.

So what do you know?

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

Hi Paul, I admit this IS all I know, although I did see reference to it on the AA site. I understand the problem with rumour/speculation/dross, so if anyone can clarify I'd be relieved to hear it is no more than urban myth. Cheers, Chris.

I don't see how any other parameter could be more important that gravel is left strewn all over bends, roundabouts etc. Luckily on a motorbike you can smell the new laid surface just before you reach it, but that is hardly a substitute for not rolling the gravel into the surface and then brushing off the excess AND leaving adequate warning signs.
Would it cost that much more in time and effort to make sure the surface is clear? Are there any accident/claim figures resulting from this type of road laying?

SMA again.

where do we begin?

High strength and long lasting. Most wearing courses today, whilst being propriety, tend to be variations of the SMA theme.

The problem with SMA is that the chips are mixed in and therefore covered in binder which is slippery until worn off by trafficking.

The loose chipping you see scattered on the surface are an attempt to counteract the early life skid resistance problems.