The M5 is at its most free-flowing near Weston, new figures released have revealed.
Highways England says drivers travelling on the motorway in North Somerset average the highest speeds between junctions 21-22 heading south to Burnham.
Drivers were clocked doing an average of 71mph, slightly above the limit.
The worst congested area was near Bristol.
An average speed of 58.8mph was recorded for drivers approaching Portishead’s junction 19 over the Avonmouth Bridge.
RAC head of roads policy Nicholas Lyes said: “More congestion means more wasted time and money, which is clearly bad news for drivers.
“Extra capacity is badly needed as Britain now has around 38 million vehicles registered for use, and in the 10 years from 2007 more than four million extra vehicles came on to the road.”
Nationally there was a 3.9 per cent increase in delays on motorways and A-roads in 2018.
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