Road quality and the specification that changed it

Anyone who drove Ukrainian roads over the last fifteen years noticed a change. It is worth explaining, because the reason is technical rather than budgetary and it is repeatable elsewhere.

The bitumen problem

Asphalt is aggregate held together by bitumen, and the bitumen determines how it behaves. Too soft and it ruts under heavy traffic in summer; too hard and it cracks in winter. Ukraine has both extremes in the same year.

The old specifications were written for lighter traffic and did not grade bitumen by performance across a temperature range. Adopting performance-graded specification meant selecting a binder for the actual climate and traffic of the road being built.

Laboratory control

Mix design tested before laying, and samples taken from the road afterwards. Without testing, specification is a wish; with it, a contractor who under-specifies is detected.

Warranty periods

The change with the sharpest incentive effect. A contractor responsible for defects for several years after handover has a direct financial reason to build a road that lasts, rather than one that passes inspection on the day.

That single contractual term did more for durability than any material specification, because it aligned the builder's interest with the road's life.

What it costs

More per kilometre, and considerably less per kilometre-year. That is the arithmetic that has to be defended when a budget is being cut, and it is the first thing lost when a programme is judged on kilometres opened rather than kilometres still good in a decade.

This is the heart of the work I have been in for twenty years. What determines the life of a road is not the budget but the bitumen grade, the mix temperature and whether the laboratory actually takes samples. When the specification tightened, the type of plant I could sell changed with it — what fixed the market was inspection, not money. On the day warranty periods appeared, the quality of the work rose by itself.