Lack of focus on planned preventative road maintenance is fuelling the UK’s pothole pandemic

Potholes seems to be appearing at a faster rate than ever and the latest Annual Local Authority Road Maintenance (Alarm) Survey from the Asphalt Industry Alliance does not make great reading. Worsening carriageway conditions and rising costs against a backdrop of a reduction in funding means the cost of maintenance repairs needed has reached £14.02bn.

More than 97% of our road network in England and Wales is maintained by local highway authorities. It is an asset valued at over £400bn and the biggest physical asset the public sector owns.

Despite the drive towards net zero, roads will still play a key part of our transportation networks and it is the vehicles using them that will change. But road quality will still be dependent on asset managers taking the strategic decision to prioritise long term resilience and lifetime value, as well as proactive, preventative interventions.

The good news is maintenance crews around the country are filling in a pothole every 22 seconds but the cost of filling them is rising too. The latest pothole fund was welcome, but £200M doesn’t go far. Nonetheless, there is a readymade solution to the pothole crisis that is often overlooked and that is surface dressing.

According to statistics from the Department for Transport, the percentage of roads – A, B and C – receiving surface dressing treatment has declined 30% since 2016. This is mirrored by feedback from Road Emulsion Association (REA) members who report a 36% decline in the application of surface dressing – and an increase in potholes. Our research with REA shows correlation between reduced surface dressing treatments and subsequent increase in potholes over the past decade.

Longer term, the DfT statistics show a steady decline of the use of surface treatments over not just years, but decades. I believe that this change aligns with the continued pivot towards shorter term funding decision making.

The decline in the use of surface treatments represents a failure to leverage the advantages that such a planned preventative approach provides.

Through the appropriate planned application of such treatments prior to the development of serious surface and structural defects, such as potholes, road conditions can be managed and maintained far more effectively as well as road lifespans extended – potentially indefinitely.

Surface dressing is the most cost-effective method, both financially and environmentally, to improve skid resistance and seal the road surface, which will stop the ingress of water and help prevent potholes appearing in the first place.

The development and introduction of proprietary finishes, while providing all the benefits described above, has also further improved the chip retention and provides a “new road” look for a fraction of the cost.

To fully resurface the same road in traditional asphalt using primary aggregate could cost up to 10 times the amount and, without surface treatment intervention, last no longer.

So, for the amount that it costs to fix potholes, an additional 3,500km of local roads could be surface dressed, preventing the need for costly and time consuming interventions in the future and the closure of roads to the public for pothole filling.

The focus on full resurfacing also means missing out on environmental benefits too. Modern asphalt surfaces are durable but by design sacrificial. Once their anticipated design life is achieved the eventual replacement uses a significant amount of high quality, expensive aggregates. These are used throughout the entire surface course and not just the contact area of the road surface.

Surface dressing uses up to 75% less bitumen and up to 80% less aggregate per square metre than thin surface asphalt courses. This ensures that high value mineral reserves can be kept in the quarries for future generations, while mitigating the added high carbon cost of transporting quarried aggregates to sites across the UK.

It not only significantly extends the service life of the pavement, with a reduced impact on the environment, but can also be reapplied in many layers over a number of years. They can help keep the road network safe while maximising the service life and restricting emissions through requiring fewer interventions and reductions in the use of equipment over the 60 to 90 year road lifespan.

By taking the required decisions to adopt longer term strategies to future proof roads and act early to prevent, rather than cure, road defects, local authorities could achieve significant cost advantages.