So the legal authority for roads is different than the legal authority for motor vehicles. The legal authority for operating motor vehicles is different than the legal authority for selling motor vehicles. This is why every time you register a car in a state for the first time it has to pass a state-specific safety inspection, but why the standard and mandatory equipment of vehicles is dictated by the NHTSA and DOT. General rule of thumb: the tallest rules govern. So New Mexico, which pretty much requires cars to have a mirror and a horn, has vehicles that are 50-state legal because cars legal for sale in one state must be legal for sale in all states. Does that make sense?

An autonomous driving system is vehicular equipment, which means its legality and governance will be covered by the DOT. Note that certain states have passed legislation making operation of autonomous vehicles legal; that's very different than sales. Sales will be governed by the same body that does seat belts, airbags, brakes, etc. So far so good?

Adding onto that: the discussion isn't "legality" so much as "contract liability." If you buy a self-driving car that will get you there the fastest way legal, and it suddenly becomes a car that will get you there "the fastest way you can afford", you're going to run afoul of price gouging statutes - after all, you bought one thing, you're getting another, and that's intentional tort.

And there's no way to get around it. If Google Carbon and Google Diamond are on the same roads, obeying the same laws, and Google Carbon has to deprecate its service in order for Google Diamond to serve its customers, then Delphi Drive has a sales advantage over both because it's got one universal level of service. Which means Google Diamond has no ability to enforce its deprecation on Delphi Drive, then nobody buys Google Carbon because you're suddenly the only loser that can't get to work on time.

Simply offering two tiers also invites congressional inquiry into your methods... and Google don't want that.

You're correct: you have no "right" to speedy traffic. However, you absolutely have a "right" to a product you paid for.

By the way: Life safety is a non-issue. 911 gets to say "there's an ambulance coming through" and every self-driving car slows down and pulls over before you even hear it. G8? Life safety. Whole 'nuther issue than "my car is faster than yours 'cuz I pay more per month."