The North Circular from Chiswick to Hanger Lane in West London has been named as the most congested stretch of road in Britain.
Analysis by transport data firm Inrix ranked London the 6th most gridlocked city in the world, behind the likes of Moscow and Istanbul.
Traffic jams cost the average London driver more than 16 hundred pounds last year.
Congestion cost the UK an estimated £7.9 billion last year, at an average of £1,317 per driver.
Costs associated with slow-moving traffic include making it harder to transport goods, reduced productivity, raised pollution and increased accident levels.
The research found that London is the sixth most gridlocked city in the world when population is taken into account.
Moscow tops the list, ahead of Istanbul, Bogota and Mexico City.