Probabilities In Plain Sight Part One: Parking Tickets

Probability and chance are baked into a lot of our daily life. Most of the time they are understandable and related to pure random events. For example the odds of being struck by lightning in the USA at any given time is one in a million.

Increasingly, I have begun to think about probabilities that are related to human behaviors and are less obvious.  For example, the cost of a parking fine reflects a number of probabilities. The probability of committing a parking offence and the probability of being caught. This must help calculate the rate of capture, the cost of which must be paid for by the fines issued.

For a fixed cost of patrolling the streets, it makes sense that the higher the fine, the fewer offenders there are, or that they are harder to capture. Whereas a lower fine would indicate that lots of tickets are issued – a combination of more offenders and them being easier to identify and issue a parking ticket to.  The consequences could be counter-intuitive, higher fines should encourage people to park illegally (as it will be less likely they are issued a ticket) whereas lower fines should discourage people parking illegally, as it suggests that the rate of ticketing for offenders is much higher.