There are only a couple hundred AV cars on the road. They are not causing the level of congestion you are trying to suggest.

Remember that these companies cannot earn money from rides right now because the CPUC has not given them the permit to do so. Once that permit is granted, the monetary incentive will be very strong. There is cost to the company for also operating an empty vehicle that they will not want to pay either. I think the incentives are aligned on both sides.