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Four of the UK's worst traffic bottlenecks occur on the Edinburgh bypass, according to new research.

The city also ranks second in a list of Britain's most congested cities, while Glasgow is third.

Only London ranked worse than Scotland's largest cities in the survey of the UK's roads by Inrix Roadway Analytics.

It found that the jams could cost drivers in Scotland £5.1bn in wasted time over the next decade.

The firm studied traffic hotspots in 21 UK cities in September 2016.

It assessed the impact of the congestion by looking at the average duration of traffic jams, their average length and the number of times they occurred.

The UK's worst traffic bottlenecks Rank UK City Worst traffic hotspot Av. duration (mins) Av. length (miles) Number of jams 1 London M25 N between J15 (M4) and J16 (M40) 20 5.88 690 2 London M25 N between J16 (M40) and J17 (Rickmansworth) 30 4.83 456 3 London M25 S between J21 (M1) and J21A (A405) 273 13.78 13 4 Edinburgh A720 W (Edinburgh bypass) at Dreghorn Barracks 86 5.4 101 5 Edinburgh A720 E (Edinburgh bypass) between A702 and A701 80 2.23 216 6 Glasgow A8 E at junction with M8 96 4.95 76 7 London A406 E (North Circular) at Powys Lane (B106) 197 1.62 92 8 London A406 W (North Circular) at Station Road (A109) 84 2.59 129 9 Edinburgh A720 W (Edinburgh bypass) between A702 and A701 76 4.77 76 10 Edinburgh A720 W (Edinburgh bypass) at Dreghorn junction 51 4.54 114

The research found that the impact of Edinburgh's 455 traffic hotspots was second only to London and was likely to cost drivers £2.8bn by 2025.

Glasgow was ranked fourth in the same list - worse than Birmingham, Manchester and Bristol. Its 357 hotspots could cost £2.3bn over the next 10 years, Inrix said.

Researchers calculated the time wasted by drivers in traffic jams across the UK could cost £61.8bn by 2025 if congestion levels are not reduced.

And in their survey of 123 cities across Europe, London was found to have more traffic "pinch points" than any other city.

It also ranked worst in an assessment of the impact of its traffic jams. Rome was second and Paris was third.

Inrix chief economist Graham Cookson said: "Only by identifying traffic hotspots and analysing their root causes can we effectively combat congestion."