Public transit gets people off the roads, though.

Certainly that's where parking tickets should go, and probably drunk driving fines. At the very least.

Earmarking revenue just gets worked around. If an agency's budget is $100M from the general operating budget, and $20M earmarked revenue suddenly comes in to that agency, their share of the general operating budget will simply be reduced to $80M.

It's the same reason why lottery revenue or (in California) bond approval propositions are typically earmarked for "noble causes" (schools, firefighters, parks...). It's a cheap promise to make, and the share of general operating revenue allocated to these departments can quietly decrease as lottery or bond financing replaces it, completely working around the spirit of the earmarking.

It sounds trivial to say but control of budgeting decisions is obtained through control of budgeting decisions; earmarking constraints are just accounting games to make spending more palatable to taxpayers.

Earmarking revenue to a "noble cause" is a great way to protect the thing that is generating that revenue. It becomes a "you don't like firefighters/children/etc" argument whenever you want to remove or reform the thing that is providing that earmarked revenue.

No, they should not. If you want to fund transit, fund it directly. It's an independent decision.

I'm just a big fan of feedback loops, I guess.

Feedback loops are cool, but ultimately money is fungible. It might be possible to legislate around this, but normally I'd assume the sort of government that is going to essentially turn their police into highwaymen isn't above saying "well, we funded the school through tickets, so we can point all the tax money at new police cruisers."

Why is funding a bus from speeding tickets a "certainty?"

Just eliminate fines altogether and give some more appropriate punishment like traffic school (which must also be free...)

After all, any law which is enforced by fines is a law solely for the poor.

You need fines, because some people don't care about anything else. You can set up a system of just points, with no fine, and people will just drive with revoked licenses. I don't know about you but my I am very rarely pulled over and there are several stretches of my life where you could have revoked my license for a year, or five, and I could have kept driving without a problem.

Maybe it's just your points idea that's not very good. If you were punished with traffic school and just ignored it they can still increase penalities and eventually come arrest you. Unless your plan involves hiding out in the mountains somewhere or something.

Laws aren't only for punishing people who have something to seize. How else do we deal with people who have no money but still commit minor infractions?

It's not my idea, it's how states take licenses away from repeat offenders, but yes I'm sure there's a better way to do it than that.

Either eliminate fines altogether or collect the fines and then burn the money in a furnace. Any system that derives revenue from lawbreaking has the perverse incentive of increasing lawbreaking.