A fine of $120, for example, is a trifling amount to a person earning $100,000 per year. But the same fine is an imposing chunk of the weekly earnings of a person on minimum wage. For the latter, that fine would be about a quarter of a weekly pay-packet, or the difference between eating well and, well, not eating. For someone on 100,000, it's merely 8 per cent, or the difference between a night out somewhere nice and just staying home. Of course, the super rich are more bothered by a shoelace coming untied.
Imposing the same fines for the same offence is egalitarian, but it doesn't lead to egalitarian outcomes. Far from it. The poor are grossly more affected or the wealthy significantly privileged — whatever floats your boat the outcome remains the same.
Grappling with these issues is hardly new. In 1774 Montesquieu scratched his chin wondering: "Cannot pecuniary penalties be proportionate to fortunes?". If you don't know, Montesquieu is one of the great Enlightenment thinkers and a person who you quote when wanting to sound intelligent at dinner parties.
But we don't need philosophers when we have the Scandinavians who have addressed the issue head on. In a number of those countries, speeding fines are levied relative to income.
In 2015, a Finnish multi-millionaire businessman was fined €54,000 ($91,000) for having a heavy foot. He was unimpressed, grumbling: "Ten years ago I wouldn't have believed that I would seriously consider moving abroad. Finland is impossible to live in for certain kinds of people who have high incomes and wealth."
And right there, even though he might not have realised it, he gained an appreciation of the big impact that fines have on poor people. Although seldom can the poor afford to emigrate in protest.
Leaving aside the odd millionaire businessman, the Finish laws appear popular; or at least they were in 1999 when a survey showed four out of five Finns supported them. It's hard to argue that millionaires shouldn't be affected by speeding tickets, and I imagine that the Finns put those €50,000 to good use. Is this approach likely in New Zealand? I can't see it.
Still, we should have a conversation about the impact of fines on certain groups — particularly because unpaid they drive people to court and into the criminal justice system leading to impacts most undesirable.
Our sense of justice is sometimes like our driving, and we should be inspired by the best of it.
Few things bring out our lack of generosity and kindness quite like getting behind the wheel during the holidays when the lanes are packed with traffic and the kids are in the back screaming.
Yet nothing casually unites us like the tell-tale flash of the headlights between motorists to warn of a highway patrol car or a speed trap ahead.
It's an informal social control that slows us down but tips our hat to fellow travellers — everyone from bogans to businessmen appreciates that.
Be warned, flashing your lights can technically be an offence but don't let that put you off. Particularly if you're wealthy.