Bike, ped, and rail infrastructure can be built at the national, state, and sometimes even local level. These things all reduce the need for owning so many cars.
Governments at any level can reduce how much they subsidize waste removal. Make people pay if they want to throw out more than is reasonable.
Carbon taxes can be levied against corporations, which would flow down to consumers and incentivize carbon-aware spending habits.
Are you in USA? What specific city/county/State goverment practices are problematic? I am interested in seeing the actual codes/laws.