If you have all the cars driving themselves they can function more like a swarm/grid of vehicles managed externally vs individual agents working against each other. This means you can have cars going like 80-100 mph but driving bumper to bumper.
Say the power cuts in a car, or worse its location updates no longer match the surrounding cars’ sensors, the cars in its mesh could immediately alert all the cars around that it is no longer updating its location and might be anywhere, so all cars in the area should go into low speed safe mode. It should be a doable to some degree.
At 60 mph the stopping distance including reaction time is typically referred to as around 80 meters[1], and that includes 20 meters of reaction time. In modern cars like Teslas it's more like 40 meters[2], but 20 meters of that 80 (or 40) is human reaction time.
If you can cut that down due to much faster computer reaction times you can get a lot more road throughput, of course a logical step after that is to consider networking the computer control, but talking about that from the get-go seems to me to be needlessly jumping several steps ahead.
1. https://www.brake.org.uk/facts-resources/15-facts/1255-speed
2. https://www.theverge.com/2018/5/30/17409782/consumer-reports...