Road congestion in the UK is costing the country's economy £7.9 billion a year, new data has revealed.
London has topped the list of the most likely places to get stuck in a jam, closely tailed by Leeds and Birmingham. On the slowest roads, drivers face average speeds of 7mph, meaning traffic moves around twice normal walking pace.
The study from traffic monitoring company INRIX has revealed average commuter spends a week a year stuck in traffic, losing up to £1,680 in the most gridlocked cities.
People in Liverpool and Glasgow have the best journeys, the cities have the lowest rates of congestion of all major British cities.
Overall, commuters in west London face the worst tailbacks. The junction of Chiswick Road and Hangar Lane is the UK's slowest.
INRIX said if the problems are not addressed they will "continue to have serious consequences for national and local economies, businesses and citizens in the years to come."
It urged local authorities to adapt to changes in road user needs to swerve economic losses.
Where are the UK's worst traffic jams?
What is the cost of congestion?
Drivers lose up to £1,680 from sitting in traffic jams, Londoners facing the worst costs and people in Glasgow getting off the lightest.
In a statement, the Department for Transport said: "We are investing a record £23 billion on our roads to reduce congestion and make journeys better for motorists – investment which is crucial for a strong and resilient economy.
"We are also giving councils record amounts of capital funding - more than £7.1 billion up to 2021, and the £2.5 billion Transforming Cities Fund will see innovative public transport schemes developed to further tackle congestion in some of England's biggest cities."