Enticing though they are, such arguments conceal a logical flaw. As a classic 19th-century theory known as a Jevons paradox explains, even if autonomous vehicles eventually work perfectly — an enormous “if” — they are likely to increase total emissions and crash deaths, simply because people will use them so much.
Jevons didn’t know that autonomous vehicles can work like a hive mind, today it’s possible.
Even if you perfectly solve crashes (doubtful, definitely not something that exists right now), the problems of microplastic pollution from tires and emissions from electricity generation are non-trivial.
Sure, it’s possible to make AVs into basically drone swarms that have perfect coordination, the problem is that unless you also kick all human-controlled cars off the road, it’s not going to work. Drone swarms don’t have human controlled drones, or even drone swarms from other manufacturers, flying through the middle of them, or they would be crashing into each other all the time.