>> We know these cars are often modified, (b)
Note that those are not the same: (a) means "of all cars modified, more are Nissan Skylines than station-wagons"; (b) means "of all Nissan Skylines many are modified".
Police officers will want to know whether (b) is true, so that they can decide whether stopping Nissan Skylines disproportionally often is justified.
Unfortunately, (b) really does not follow from (a). For instance, (a) is true even if there are 0 modified station-wagons and a single modified Nissan Skyline. If only a small fraction of Nissan Sklyines is modified, cops are going to have to stop many, many Skylines before they hit one of the few modified ones.
Even worse, the only way to know how many Skylines are modified is to check each and every one of them (or stop "enough" of them and extrapolate).
On the other hand, cops will want to catch any illegally modified car. So they have to wonder how many other modified cars they let slip by if they're going after Nissan Skylines more than other cars.
If the cops wanted (or were able) to do proper data-driven policing or whatsitcalled, they should make a list of all the types of car they found modified in a particular time period, count how many times each type was modified, divide by the total and go after the ones with the highest ratio, and that only if the ratio is "high enough"- which again depends on exactly how many cars were modified in that time period.
But of course, all this is hard to do and costly, so cops will go by instinct and probably apply unwarranted prejudice- and get very sub-optimal results.
Modifications to vehicles here are mostly not permitted or have to be certified by an engineer, including engine modifications.
Now it is clear to anyone that say, a Nissan Skyline, is much more likely to be modified with non-permitted modifications than the station wagon taking the kids to school.
Yet there are many complaints from Skyline drivers that they are constantly being stopped and it's not fair treatment.
So the argument from one side is "We know these cars are often modified, so we use that information to inform who we stop for spot checks". The argument from the drivers is of course "I did nothing wrong so I shouldn't have to deal with constantly being pulled over".
The challenge for me is that both sides make sense, yet there is clearly downsides to cattering to either side too.
Without the informed stops you will get less illegal cars off the road, with the stops you incur on peoples privacy and ability to go about their day.
The unbiased solution would be to stop more cars but randomly. The Skyline drivers still get stopped just as often, but so does everyone else so they can't say it's unfair.
But that is dumb, and only really solves the problem of political correctness.
The other option is to just accept that more modified cars will get away with it for longer.
Now there are other options in this circumstance, like mandatory vehicle inspections each year for example.
But thisbone thought experiment really made me think deeply about racial profiling and how complex the issue really is, and how damaging it can be to the individuals being profiled.
To be clear, I think racial profiling is far too damaging to be a solution to anything. But I can see the logic path people take to get to it. Even if they do not make the next step to seeing the damage it causes.