Hundreds of drivers were forced to sleep in their cars overnight on Wednesday following a pile-up on the main road linking England and Scotland.
The A74 between Carlisle and Gretna is just one of a number of notorious routes across the UK loathed by drivers because of the likelihood of jams.
RAC spokesman Phil Hales says the massive disruption caused by a three lorry pile-up on the A74 came as no surprise to him.
"The area around the A74 is definitely a blackspot.
"As soon as something happens it will always cause severe delays."
This is largely because the road is the major route from England to Scotland, taking in a lot more traffic than the A1 route through Edinburgh.
The A74 is a relatively short stretch of road compared with what Mr Hales sees as the largest and worst blackspot in Britain - "pretty much everywhere around the M25".
"The problem is that as soon as something happens that closes the road or causes disruption there's a significant knock-on to surround alternative routes."
He cites a fatal tanker crash between junctions 5 and 6 last month which left an estimated 6,000 people caught in traffic jams on the motorway, with many more stuck on connecting roads.
"With the volume of traffic it has every day the M25 copes well enough but as soon as there's a problem involving the road being closed or lanes being closed, that really does show."
Most problem areas shared common characteristics, he said.
"Where there are convergent points it will get busy," he added.
The M1, between junction 22 and junction 26, in the Midlands, is a classic example of this with the convergence of the busy A42 and M1.
That, coupled with traffic for East Midlands Airport and the cities of Leicester and Nottingham, meant the stretch "was frequently mentioned" on traffic reports.
Similarly, the stretch of the M6 between junctions 6 and 10, another Midlands blackspot, is joined by both the M5 and the M42.
Mr Hales identified junction 23 to junction 33 of the M4 - past Cardiff and towards the Severn Bridge - as a further blackspot.
The Freight Transport Association says its members are fed up of the "constant delays" they face on Britain's motorways.
The FTA says more money must be spent on expanding the UK motorway network.
"We're very anxious about the inadequacy of the total network," external affairs director Geoff Dossetter said.
"In the last 10 years we've seen a 33% increase in motorway traffic and only a 6% increase in capacity."
Congestion cost the transport industry an estimated £20bn a year, he said.
He said the government needed to invest in the motorway network "in order to save some money".
"At the moment, we see no hope in sight and it's clearly going to get worse," he added.
But Mr Hales, of the RAC, said it was not possible "just to build our way out of the situation".
"We don't have the space nor do we wish the environmental impact of building more roads," he said.
But he said "one good bit of news" was the success of the one-year-old M6 toll road which links junction 4 of the existing M6 at Coleshill, Warwickshire, with junction 11 near Cannock, Staffordshire.
Its operators Midland Expressway Limited claim the toll saves motorists approximately 45 minutes on an average journey time.
"The toll road provides motorists with a choice - they can pay if they want," Mr Hales said.
"In that respect, it's been a success but I wouldn't necessarily say that means there should be toll roads everywhere."
Richard Eastman, forward planning director for the Highways Agency said: "I think that the government does regard motorway widening as quite a high priority.
"I think the points that the FTA have made have been taken on board. We already have quite a large programme of motorway widening."
He said the M25 between junctions 12 to 15 had recently been broadened, while widening on the M1 between junctions 6a and 10 were planned for the summer.
Future schemes planned over the next three years were widening the M25 between 2b and 3, and the M1 between 21 and 30.
But this was not the only answer, he said.
"We are looking at the possibility of a car-share scheme on the M1 and in the long-term the Department of Transport is looking at a charge for road-users," he said.
"We have got to look at a whole package of measures."