This sketch shows the above( which has R1- my residence building and other highrise apartments) and the underground station which is a mix of electric cars and metro rails.
I see the feature having more sustainable cities so all cars are both self-driving and electric powered. These cars can carry a family of 8 and can also carry two only two people. These cars are owned mostly by the government but civilians can invest in them making many gains. For instance, a civilian purchases the car and takes 40% of the profit. Families get cheaper monthly( $10) or yearly plans while others pay $20 per month. These cars operate at high speeds and use algorithms that allow them to move in sync with the other vehicles; therefore, minimizing traffic. Consider these cars as the Uber of the city. Furthermore, the underground stations have enough seating to accommodate the public as they wait for their train or car. They also have small grocery stores.
In the above ground, transportation is a little different. All residence buildings are linked through tubes which have their own terminals. These tubes house a new form of transportation called the "Turbo chairs" or Hover stream. These chairs move much quicker than electric cars and are inexpensive. The main drawback is that this form of transportation can only be used within a city, it does not link to other cities. All cities are mixed-used and compact and are walkable. Residence buildings have businesses at their ground floors.