We all know the pitfalls of riding a bike over spilt diesel but have you ever heard of Stone Mastic Asphalt? How can a rider on a perfectly straight, dry road doing 45 mph apply the brakes gently and find himself in a ditch? Well the road had been re-surfaced 6 weeks earlier with the aforementioned stuff  which can be so slippery that contractors are supposed to leave out warning signs for some weeks after!

There have been various BBC TV and radio programs about the dangers of using SMA and some countries now ban its use. SMA is deep black in appearance and white lines show up on it vividly. It looks like the perfect road surface but is a classic example of appearances being deceptive. Its use is becoming widespread in this country . It is thought that the problem stems from it being porous so water soaks through it instead of remaining on the surface. The downside is that this makes the oil content of the asphalt rise to the top. It appears that the Highways Authority is well aware of the problems and dangers that SMA poses to the motorcyclist.

It is one of the ingredients, a binder material, which gives SMA its low skid resistance. 3 ways of dealing with it are suggested; the first is to spread a type of grit on the road surface but this apparently creates it’s own problems. Secondly, warning signs can be put out, although these are possibly of limited affect. The third most popular solution amongst Highway Authorities is simply to wait for the binder to be worn away by the passage of traffic! How long this takes will depend on the amount of traffic using the road. It can take weeks, months or even years. Needless to say the strip between the wheels which is least travelled will take the longest to wear. 

There is a petition on the government website:  http://petitions.pm.gov.uk/SMAsphalt/ where you can register your disgust at the use of this material.