Mr. John McLaughlin:

Everybody works to the same NRA road works specification across the country but different materials can be selected from within those. The best of these would be hot-rolled asphalt, as seen on national roads, which requires a firm base and a good foundation. It cannot be put on roads liable to settlement because it cracks. Although it is the best and most expensive, it would not be useful to put it somewhere it does not last. Dropping down a level would bring us to bitmac, or dense bitumen macadam, with surface dressing of tar and chips. That is the next grade and it is a bit cheaper; it also has more flexibility and goes a bit further. The lower grades would be referred to as wet mix with surface dressing, which goes even further and is more pliable. That is used to a greater extent on local roads. That is the reason we see differences between motorways and national, regional, local and tertiary roads, although they all operate to the same specification. We should also mention the issue of keeping water off roads, which is very important, especially for unbound materials.