Whether to means test speeding fines is an interesting argument.
Basically, it depends on whether you consider the necessary role of the fine to produce a degree of punishment and 'sting' regardless of what you earn, obviously set amount fines graduated along a basis of how far over the limit you were caught won't achieve this. If the financial repercussions of being caught speeding are to be consistent across the wealth range then a fine proportional to your total wealth is exactly what is required (or other indirect means tests could be used like car seizure laws but they're not without issues, like the Perth GP who had his Ferrari confiscated even though his mechanic was the driver, not that our Liberal party saw an issue with this). However, the minimum amount must remain prohibitive to everyone, you can't just have someone who is basically worth the cash in their pocket, driving a bunky car (which in all seriousness should be defected but they never are) be given a $2 fine because that is all they're worth.
So it is a bit of a balance, however I'm not sure Australia would ever take on such a principle, even states like NSW with their immense fines (although it could be beneficial to their current financial state, kind of like California considering legalising and taxing marijuana). I'm not even sure it would be a policy worth implementing, my gut feeling is the probability someone speeds is inversely proportional to their total wealth (the less wealthy you are the less likely you will be to stick to the limit) although it wouldn't be a particularly strong relationship, even after accounting for other factors such as gender and age. I'm not sure if someone has done that research though, wouldn't be surprised if it has been done.
