A human at Waymo would likely not be found responsible, except if actual negligence or intent could be traced to that person. Waymo the corporation would be responsible, if their vehicles caused damage or injury. For traffic violations, presumably they could be fined, or even their permission to operate could be revoked if there are persistent problems.

For an example of how that plays out with a malicious corporation, look up how much Fed Ex and UPS pay in parking fines/tickets in NYC.

Urban myth is that a previous version of the ticket paperwork required that the vehicle manufacturer be accurately filled in, and this was one of the reasons for UPS trucks being so plain/unmarked, and since that could not be derived from the (lack of) badging or the registration paperwork (which version for trucks did not have the matching entry requirement), UPS didn't have to pay tickets while other services did.