Not the same thing but somewhat related. Some European countries have fines for e.g. traffic offences that are proportional to you income for the year the offen

Not the same thing but somewhat related. Some European countries have fines for e.g. traffic offences that are proportional to you income for the year the offence is committed in. I think that this works quite well in terms of meaning that rich and poor have the same disincentive not to speed.