The key word here is "urban". I ride my bike around the city core sometimes just for fun and I can easily keep up with cars because they are going so slow. Now imagine how many bikes you could fit on a two lane road vs how many cars. Obviously if the car is coming from the suburbs its going to be faster.

> Also, serious question: if electric SDCs became widespread, would it still make sense to advocate things like bikes?

Yes, absolutely yes. The cars would still have to go somewhere after they have dropped off their occupants. Hopefully we will get on-demand carpool services that allow us to have vastly fewer vehicles on the road, which would free up space for bikes and other public transit.

> You can't transport a family of three or a baby as safely in a vehicle smaller than a car

Not everyone can use a bike of course. Some will have to use public transit, and yes some will have to use a car for various reasons. The streets don't have to be car-less, we just need to get enough cars off the road to ease congestion and be able to turn existing lanes into bike lanes or public transit lanes. Once good reliable and quick public transit exists, there won't be such a strong incentive to own a car.