Why not ban cars entirely? Because people will loose thousands and it'll destroy the economy... The motor industry and fuel industry bring in billions every year. Not to mention the amount of jobs that would disappear and the amount of unemployed people it would generate, getting a job is already a struggle for some. Given that we're a capitalist society, cars would never be banned because the industry rakes in so much money.
Move people living in rural areas to cities? Not practical, if they're living in a rural area then they obviously don't want to live in a city. Not to mention the cost of living is higher in cities and not just everyone can go buy an apartment just like that...
Automated trains? Getting rid of human drivers, again, jobs would disappear and the number of unemployed would skyrocket.
We should ban China from Earth, the idea sounds just as stupid yet far more effective.