I wouldn't support fines based on income for all violations but I believe some might be warranted. Take speeding for an example. A poor person could have half to their entire paycheck for a week nullified due to going 1-4 mph over the speed limit (least expensive speeding ticket in USA) while it wouldn't affect a rich person at all. My sister's husband is one of these semi "rich" people that doesn't give a fuck (he probably gets at least 3 each year). The fine is more likely to change a poor person's driving habits.