But the goal is presumably to try and persuade him not to speed again?

The goal should be to persuade everyone not to speed in the first place.

you keep talking in dollars and not hours

if the fine is "one week of income" and you don't want to lose a week then you won't speed

if a speeding ticket was 5 cents everyone would speed every day... and this is the status quo for the rich since the fine is to their income what five cents is to most others

so we fine people enough that it affects them in a proportionate way to make the likelihood of changing their behavior equal, rather than only changing the behavior of the poor

Dollars is roughly proportional to hours for the guy at the bottom of income levels. I'm not sure it is for people at the top, choosing which assets to liquidate in which year.

How do you persuade “everyone” when the primary deterrent is a fixed fine that doesn’t scale relative to lifestyle?

So now we're not looking at fines in relation to income but lifestyle?

I just think you cannot scale fines in relation to income/lifestyle/anything else financially. You can scale it, but you can't hit people with different incomes, assets, etc. in the same fashion, which ultimately smells of a bad system to me.

So what would you recommend?

Anything else.

The points system seems sufficent to me for most driving offences, beyond costs. But community service, prison time, curfews, anything which is equivalent and not open to manipulation.

I wonder of all of the options what the speeder would have chosen - I suspect he would pay the money and move on.

How would that even make a difference?

This statement does not support the argument that you were making in the first place