- restrict access to certain areas like city centers for pollutant cars
- stop the manufacturing of cars using fossil fuel completely (the EU plans that for 2035)
- make public transportation cheaper or even free (Luxembourg did this)
- advocate the health benefits of not using a car for short trips via campaigns in differentmedia. it's cheaper and healthier to walk or ride a bike etc. whenever possible.
- make public transportation, e.g. trains, better and more time efficient (China invested a great deal of money into its train system)
- and possibly more I can't think of at the moment