About this problem there are many opinions as to allow only public transport in cities. There are arguments both for and against it.
On the one hand using only public transportation in cities can be beneficial for the environment because it would pollute less. It would generate less traffic and it would be easier to move around the city.
On the other hand, public transport may have disadvantages as the waste of time waiting for the bus and it will take us longer to get to places.
To sum up, in my opinion, I would not accept to have only public transport in cities like Granada in which public transport is a disaster because it would make the lives of people more difficult, but in cities like London and Madrid, where the public transport is efficient, punctual, regular and comfortable for citizens, I obviously would accept to have only public transport.