And yes, speed limit laws, do change over time.
And no, you can't be punished for having broken a speed limit in the past, that is not in effect today.
Parent's comparison seems rather apt.
If society A says the speed limit is X and society B it's Y and society C it's infinite. What's the point that speed is objectively measurable?
Society A and society B won’t disagree on whether something is moving at 150km/hr.
And yes, speed limit laws, do change over time.
And no, you can't be punished for having broken a speed limit in the past, that is not in effect today.
Parent's comparison seems rather apt.