"No city would accept autonomous cars if they create traffic jams,"
The man obviously hasn't had any dealings with British local government, who actively seek to create traffic jams that they can use in their War on Cars, and for the promotion of their beloved buses.
If crap-headed junctions don't create enough congestion, then they deliberately re-phase the traffic lights, or create more poorly utilised bus lanes and squeeze more cars onto less tarmac. Or they institute 20 mph speed limits that actually worsen safety, and when that becomes public knowledge claim they "can't afford to remove them". Or they simply don't repair potholes.