A massive carbon tax, which would impact the most profligate the most.
Fund better, and affordable public transport (free for the most disadvantaged) - and freight trains - short distance delivery from railhead distribution centres - by electric vehicles (charged with renewables) - and bicycle rickshaws in towns .
Remember that 'fuel crisis' we had a while back..?
Suddenly the roads were beautifully quite for cycling, and walking.
People realised maybe they didn't need to drive about so much*.
Then everyone (not just the plucky / lucky few) could cycle and walk more with confidence.
Of course special dispensation for those with disabilities.. Carbon tax funded electric cars.
OK next problem???
*the 'Ash cloud' was great too.. No contrails scribbling on our beautiful skies, no noisy planes.