On INRIX’s annual scoreboard of congestion in cities, London ranks sixth in the world, like it did in 2017. The cost of congestion is estimated to be £1,680 per driver, with the average last-mile speed at 7 mph. For the whole of the UK, it is estimated that drivers lost £7.9 Billion due to traffic congestion during the year. In terms of other EU cities, Rome ranks 10th, Berlin 15th and Paris 18th.
You can access the full ranking here.