The average driving speeds in London could slide to less than 6mph as congestion in cities triples over the next three decades, according to new research.
Engineering firm Bosch warned that gridlock in the capital will force typical speeds down from 17.4mph today to 5.8mph in 2050.
The situation is expected to be even worse in central London where drivers could be left crawling at just 2.6mph, which is below the average human walking speed of around 3mph.
Bosch claimed the increase in the population of the world's largest cities to six billion by 2050 will have a "severe effect on our transport systems", leaving streets "almost at a standstill".
Old cities such as London are "not designed to cope" with the rapid growth in traffic volumes, the report warned.
Some 959,000 new cars were registered between January and March in Britain - a record for the first quarter. The study warned that even after completing frustratingly slow journeys in London, drivers will spend much longer searching for a parking space over the next 30 years. Increased congestion will increase the time spent searching for a space each year from 67 hours today to 200 hours by 2050 - equivalent to more than eight days. Bosch published the research at a central London event showcasing its latest transport technology such as driverless cars and pods, and electric bikes and scooters. Members of the public were taken on laps of the Somerset House courtyard by a pod which operates using a combination of features such as lasers, cameras and GPS. Pods are currently used in at least 19 countries around the world, including a trial in Greenwich, south-east London. They are a so-called last mile transport solution, such as for journeys from a train station to a housing development. The event also saw a concept driverless car in which passengers can control the vehicle's settings using hand gestures. Bosch UK president Dr Steffen Hoffmann claimed autonomous technology can make car journeys more enjoyable even if motorists still find themselves stuck in traffic. He told the Press Association: "It's about convenience. If you're still stuck in traffic, you can have much more quality time when you don't have to concentrate on the road. "They can use the time in a better way. "From Monday to Friday you use the same route on the way to work. It's mostly stop and go. That's typically not fun driving. "People would probably be very happy if they could press a button, let the car drive itself and use the time to do something else, read the newspaper or check your smartphone or work or whatever." Dr Hoffann added that he estimates the "full autonomous experience in a complex urban environment" will be in use by around 2025.