Level of Service - Level of Service in The UK

Level of Service in The UK

The Level of Service measure is much more suited to American Roads than roads in Europe and the UK, however the Highway Capacity Manual is used in the UK. The technique does find its way into UK textbooks, however in practice it is sparingly used in transportation analysis. The individual countries of the UK have different bodies for each areas roads, and as a result detailed techniques and applications vary in Scotland, England and Wales, however in general the practice is the same.

In the UK rural and urban roads are in general much busier than in the U.S, and as such service levels tend to be to the higher end of the scale, especially in the peak commuting periods. It is acceptable for roads to operate at 85% capacity, which equates to D and E LOS.

In general the principle the UK uses is to take the volume of traffic in one hour on the road and divide by the appropriate capacity of the road type to get a v/c rating. This v/c rating can be cross-referenced to the textbooks which publish tables of v/c ratings and their equivalent LOS ratings. The lack of definitive categories towards the D, E and F LOS ratings limit the use on UK roads, as an D or E category on an urban road, would be acceptable in the UK.

In certain circumstances the UK shortens the LOS categories to just A-D. The first 2 categories indicate free-movement of traffic (i.e. under 85% capacity), the C category indicates reaching capacity 85%-100%, whilst D indicates over capacity. Little reference to this can be found in textbooks and it may just be an 'unwritten engineering practice', agreed with certain authorities.