It's regressive in some ways, and not in others. If you're completely unemployed, you might not drive but generally speaking low wage workers have to do the most commuting, often living furthest from their job, in places with poor transit access if any. They often are forced to use the least efficient older vehicles as well. The biggest savings however will be in commercial transport which would have been passed on through rising costs for groceries and essential goods, which again will hurt those already struggling more than the wealthy. Sudden unpredictable price shocks are always absorbed by the poor the most.