Mostly make them more fit for purpose.

- Range: Most cars are only used for short local trips, school, work, shopping, social event etc, but they're designed more as endurance vehicles for cruising at relatively high speeds. Using a hybrid powerplant, smaller engine and smaller tank would make them a lot more efficient. Electric motors are better at acceleration and deceleration anyhow, they have torque for days.

- Size: Most cars are designed for five passengers *and* cargo but they run mostly empty most of the time. For most people a one or two seater car would make more sense. And even for the family vehicle it should be possible to use modular attachments to expand capacity as needed.

- Complexity/Monopoly: Cars are far more complex than they need to be by design, in order to force consumers to depend on a repair and parts monopoly. Innovation is also curtailed through direct government intervention and indirect intervention such as IP.

Cars can and should be smaller, cheaper, more flexible, more efficient, easier to repair and easier to innovate. Doing this would make most of the problems associated with the transport market go away, including the manufactured ones.