The quality of the UK’s roads is worsening, according to data from the RAC’s Pothole Index, which shows there has been a 31% increase in pothole-related faults attended by its patrols in the second quarter of 2017 compared with the same period last year.

Between April and June RAC patrols attended 3,565 motorists whose vehicles had suffered broken suspension springs, damaged shock absorbers or distorted wheels – issues that could be largely attributable to poor road surfaces – in contrast to 2,725 similar breakdowns in the same three months of 2016.

The RAC Pothole Index also has a 12-month rolling average of pothole-related breakdowns corrected to remove unrelated longer-term effects of weather and improving vehicle reliability, and this also indicates a worsening picture after five successive quarters of improvement.

As of the second quarter of 2017 the index stands at 2.2, having begun at a base of 1.0 in 2006. This is an increase on the first quarter of the year when it stood at 2.08 – the lowest figure recorded since Q4 2008 – and the first increase seen since the beginning of 2016. Nevertheless, overall road conditions are much better than the high point of the index of 3.5 in January to March 2010.

RAC chief engineer David Bizley said: “After a period of steady improvement, it is disappointing to see an unwelcome rise in the number of pothole-related breakdowns RAC patrols dealt with in the second three months of the year when compared to the same period in 2016.

“The most worrying aspect, however, is the fact that this year’s weather has been so much milder and drier than in the equivalent six months last year and, for this reason, we should have expected the numbers for the second quarter to be lower.

“A short-term reversal in the fragile improvement in surface quality of the UK’s roads may not seem much to be concerned about, but we fear it would only take a spell of very cold or wet weather for the improvements of the last year or two to evaporate and for the nation to find itself in a situation when we would once again be seeking emergency funding from Government to address the worst affected roads.

“While there is now long-term investment in place to maintain and improve our major roads, local roads still play a vital part in enabling the economy and remain motorists’ number-one transport investment priority for central Government. They must not be neglected and this is why we are still calling on the Government to recognise their national significance and to mirror their approach to major roads and ring-fence a dedicated fund for this purpose.”