The city’s medieval layout is a dense maze filled with cars, buses, delivery scooters, bikers and jaywalking pedestrians. There are roundabouts upon roundabouts. Restricted bus lanes emerge and disappear again. On one-lane streets, drivers traveling in opposite directions intersect and must coordinate in an unspoken language to get through.

The failure rate for a driver’s license test in London is just over 50 percent.

This week, a small number of autonomous robotaxis will enter the fray, carrying London passengers for the first time. Fifteen cars operated by Uber and the British autonomous vehicle start-up Wayve will be available for ride-hailing through Uber’s app as part of a safety testing period. The cars will have a safety driver present to take over if needed, as government regulators weigh eventually approving wider deployments.