More than half of the UK's A-roads have failed to be classified as safe in a study covering 28,000 motorways and roads.
Research by the European road assessment programme (EuroRAP) also found that a quarter of Britain's motorways rated poorly.
However, it was single carriageway A-roads that were classified as most dangerous, with EuroRAP's experts calling for improved junctions, road markings, road surfaces and signage.
As well as the roads rated as poor, the research labelled 58% of A-roads as either neutral or poor for safety.
The A537 from Macclesfield to Buxton has consistently rated as one of the UK's most dangerous roads, with the latest study reporting 27 accidents that resulted in death or serious injuries over the two-year survey period.
A four-mile section of the A675 from Higher Walton to junction 3 of the M65 in Lancashire was also noted for the fact that half of all fatal or serious injuries occurred at junctions.
The report found that 80% of 'persistently high-risk' roads were around the Buxton, Humberside, Macclesfield, Sheffield, and Yorkshire areas.
EuroRAP's report also noted that improvement work on a 27-mile section of road between Carmarthen and Llandovery in Wales had contributed to a cut in accidents of more than 80%.
EuroRAP spokeswoman Dr Joanne Hill said: 'It is the busy non-primary routes - the ones that take volumes of traffic at all hours between towns and villages across Britain - that the new survey shows represent the highest risk, accounting for 62% of all road deaths.'
A Department for Transport spokesperson said: 'We've cut the number of people killed or seriously injured on the roads by more than a third since the mid-1990s. That means almost 17,000 fewer deaths or serious injuries in a year.'
Ten most dangerous roads
1) Road: A537 Section: Macclesfield - Buxton (A54)
2) Road: A686 Section: Penrith - Haydon Bridge NE /NW
3) Road: A5012 Section: A515 - A6
4) Road: A621 Section: A619 - Totley
5) Road: A5004 Section: Whaley Bridge (A6) - Buxton
6) Road: A54 Section: Congleton - Buxton (A53)
7) Road: A62 Section: M62 J27 - A6110
8) Road: A255 Section: Margate - Ramsgate
9) Road: A285 Section: A27 - Petworth
10) Road: A675 Section: M65 J3 - Bolton