Utilities' reinstatements of the highway

Studies in Europe and North America into the effect of utility works on the performance of highways have shown that trenching can have a detrimental effect on both the surface condition and the underlying structure of a highway, thereby shortening its service life. Previous research by the CSS in this area found four kinds of damage that may result from trenching activity:

• the possibility of the excavation process weakening the adjacent pavement, which then further deteriorates after a reinstatement is completed;
  
• the creation of a weak boundary between a reinstatement and the adjacent pavement;
  
• a deteriorating pavement that may cause an adjacent trench to fail earlier than expected;
  
• surface deterioration and visual disbenefit arising from the works.

The Traffic Management Act 2004 has provisions to enable highway authorities to recover funding (contribution to costs of making good long-term damage) from those responsible for the long premature deterioration.

This report describes the methods used to determine the additional maintenance costs borne by authorities as a result of premature highway deterioration, and goes on to develop a schedule of charge rates that could be levied against those opening the highway, in order to recover these costs.

The research was undertaken by TRL with funding from the CSS. A pdf version of their report is available here [060202 - trenching_charges.pdf]. Parallel research by TRL into the compliance of utilities' reinstatement trenches with the national specification is available here.