Fewer major roads in North Somerset are meeting adequate standards, new figures show.
The RAC said it was "concerning" so many roads had deteriorated, warning around 1,500 miles of road were now significantly worse than they once were.
Local authorities classify roads as red if they should be considered for maintenance, amber if maintenance may be required soon, and green if no further work is needed.
In North Somerset, 82% of A roads and motorways were green, 17% were amber and 1% were red in the year to March, Department for Transport figures show.
The percentage of 'green' roads has fallen from 85% in 2018, when current records began.
Nationally, the percentage of ‘red’ roads has remained relatively stable, rising slightly from 3% in 2018 to 4% last year, but the percentage of ‘green’ roads has fallen steadily, from 74% to 68% over the same period.
RAC head of policy Simon Williams said: "While the percentage of A roads that are deemed to be in the worst ‘red’ condition doesn’t appear to have gotten any worse, it’s concerning to see that more roads that were in reasonable ‘green’ condition have now deteriorated to ‘amber’ status.
"Unfortunately, this is also the trend with B and C roads with 3% more of these now being categorised as ‘amber’ which means approximately 1,500 miles of road around the country are now significantly worse than they were.
"Drivers’ surveyed for this year’s RAC Report on Motoring listed the poor state of local roads as their number one motoring issue of concern."
In North Somerset the data also shows 1% of A roads, and 7% of B and 'unclassified' local roads, known informally as C roads, required investigation for maintenance as of the end of March.
Councillor Adam Hug, transport spokesperson for the Local Government Association, said councils already spend more on highways maintenance than the allocation for it they receive from Government.
He added: "Greater long-term investment is needed if we are to reduce the £16.3 billion repair backlog and the Spending Review provides an opportunity to give councils this funding certainty.
"Councils’ highways departments also need five-yearly funding allocations, on a par with National Highways, so they can develop resurfacing programmes which prevent potholes appearing in the first place."
In total 61 miles of A road and 631 miles of B, C and unclassified roads in North Somerset received maintenance treatment in the year to March.
A Department for Transport spokesperson said the previous Government made unfunded promises on infrastructure, and it would instead secure sustainable long-term funding for councils, with further details to be announced after the next Spending Review.
They added: "For too long, this country has suffered from a pothole plague, which is why we’re investing nearly £1.6 billion for the next year alone to help fix up to a million more potholes annually.
"We are absolutely committed to repairing our roads, and will provide local authorities with multi-year funding settlements, helping them to better maintain their roads and prevent potholes forming in the first place."