Proportional fines help, but they aren’t perfectly fair.
The other end of the scale is interesting too - how do you disincentivise/punish for people who don't have any money and just aren't going to pay any fines you give them (i.e. the homeless)?
There are people who just park their car anywhere and paid parking tickets, they really don't care because it was too small amount of money.
If anything, people should realise the level of inequality has become. How unfair and unjust the system has made against the bottom half of the population.
Then someone on minimum wage of $30k will just get demerit points while someone on gross income over $200k will pay $8,500. Given that their “taxable income” after deductions is around $80k they will feel that sting.