Lifted this from another forum; wondered if anyone else had heard about the issue? I know we have at least one resident expert.
If you want to follow the whole thread, link is
http://www.mx-5.com/Community/forums/ShowThread.aspx?PageIndex=1&PostID=31508 STONE MASTIC ASPHALT AND ITS DANGERS
Reading through as much of this website as I can it has become clear to me that its members appear to be in ignorance of the fact that the government, through the local Highways Authorities, is busily covering the roads of the UK with a surfacing whose skid resistance, i.e. slipperiness, is so suspect that its use is banned in some other countries. I refer to a material known generically as stone mastic asphalt, or SMA.
I became painfully aware of SMA about a year ago. I am a seventy year old retired police inspector, who has ridden motorcycles for fifty-four years, all over Europe and North America. I was one of the first to pass the IAM motorcycle test, and I sat for twelve years on the motorcycle committee of the RAC. I think I can truthfully claim to be an experienced motorcyclist and, yes, I also own a mark 3 MX-5. I was riding a brand new Moto-Guzzi 750 motorcycle at 45mph along the A1124 in Essex, at just before noon on a fine Sunday morning. Traffic was very light, and the recently re-surfaced road was dry and smooth, i.e. perfect conditions. A car a hundred or so yards ahead of me indicated a right turn, so I shut off a little and reached for the brake. The next thing I knew I was bouncing along the road, wondering what on earth had happened. I sustained a badly broken wrist as a result. Needless to say I was mystified as to what had caused me to skid, until the police officer who attended said he could see no sign of anything that would have made me come off, but the road surface felt "greasy". This reminded me of a documentary I saw, and if you log on to
http://news.bbc.co.uk/2/hi/programmes/file_on_4/4278419.stm you can read a summary of the programme yourself.
SMA is well-liked by local authorities because it is hard wearing, porous and quietens tyre noise to a surprising degree. Instead of rolling granite chips into hot tar, the chips are pre-coated with bitumen. The bitumen is made to stick to the chippings by an oil-based mastic, and this is where the problem lies. Until the mastic is worn off the surface, it has a low skid-resistance (although the authorities will deny this). There used to be an article on the Highways Authorities and Utilities Committee website in which this was clearly admitted, but it seems to have been removed just recently, and I am reliably informed that it is being re-written. Fortunately I took a copy. SMA was tested by the government's Highways Agency in the early 1990s, and found to be dangerous enough for its use not to be recommended. However, something happened subsequently to prompt a change of mind (I wonder what that was? Change of government perhaps?).
Following my accident I have learned that another rider crashed on the A1124 some weeks before me and was killed. Another with thirty years experience came off in Dorset and has lost the use of his left arm. Don't think you are safe on four wheels. I have read on that BBC website of a police officer losing his wife when he skidded on SMA in South Wales; a doctor being killed in Shropshire; and the latest to come to my notice occurred on the A31 at Barton, in Hampshire, in which a driver was killed after losing control on a corner. Following the inquest in this last case, the SMA was removed and replaced with Shellgrip. Even the British Horse Society has been protesting because horses lose their footing on it. Why has there not been an uproar from the motoring community?
My insurance company has instructed solicitors to pursue a claim against the council, and if anyone has any information that might assist this I would be obliged if they would let me have it.
Incidentally, does anyone know what was used to re-surface Bristol Airport runway that made it so slippery that airline pilots refused to land on it? Sounds awfully like SMA.
