You would have thought the cars could at least hover above the road making everywhere pedestrian friendly and have elevated expressways for non local trips.
I actually prefer that they still use wheeled vehicles in addition to the occasional hover cars/bikes and aircraft. Ubiquitous hover cars make a nice joke when you're lamenting their lack of existence in the "future" year that you're now living in, but if put in practice they would be a nightmare.
Think of how many traffic accidents, mechanical breakdowns, and intoxicated or sleepy or texting drivers (which could be alleviated with a driverless system, but only if they chose to engage or it or didn't have a choice at all) you see, and then imagine if all those people had control of their own airplane flying over densely populated areas. It would be raining cars.
The only way to make sure this wouldn't happen is to create some kind of guaranteed multiple redundant system whereby even if all power was lost, every other system failed, or if the driver was an idiot, the car would never collide with another vehicle, pedestrian, or building and would just gently set itself on a clear patch of ground in case of emergency.
Now, you'd think that would be possible in Trek times, but even if this film we see the Enterprise lose all power and fall to Earth, and a spacegoing military ship of the line would be a hell of a lot more finely tuned than your father's Oldsmobile. Plus, these people have cracking bridges, shifting gravity generators over giant pits o'doom, and a desperate need for surge protectors. OSHA would not be happy.
