Traveling backwards into the future

In a world of AVs, cars can in principle as easily go backwards as forwards ... What does that do to street  and vehicle design?

Streets in suburbia often are designed as cul-de-sacs with a loop at the top so cars can turn around while going forward. Streets are designed to be wide so firetrucks can turnaround instead of backing out. But in the future, none of that is necessary. The familiar lollipop shape of cul-de-sacs can be rethought, we might see more stubs.

Further, the need for through streets for vehicles on roads with the functional purpose of land access also is mitigated, when cars can easily backup in a second lane, the street can be cul-de-sac-ified.

Parking lanes can be reduced in size General with AVs, but especially with easier back-in maneuvers.

On vehicle design, people don't like moving backwards. (Though arguably it might be safer, it's what we do with child safety seats.)  Sydney trains have reversible seats so people can face forward when the train reverse direction. Car design might be similar, so people don't suffer the discombobulation of backwards movement. A rotating seat in a narrow vehicle may be tricky, but why not?

Other vehicles that can move backwards (like ferries) generally operate forward. What optimizations does a preferred direction present?