Thanks for your answer, Hassan (and apologies for my misspelling of the word tint in my initial question!).

So then WHY do I see all these cars with nearly black windows on them, if you're not allowed to tint the windshields?

I get annoyed because invariably it is THESE cars, with the abnormally dark windows, whose drivers are the most arrogant on the road. They're the ones who ride the shoulder and cut into lines, who tailgate and flash their high beams at you, who make a left hand turn from the far right lane because they'd rather endanger YOUR safety than go one R/A out of their way...

And I think that they are arrogant drivers, in part, because they know that nobody will be able to identify them as the driver should someone choose to go and file a complaint at the traffic police.

To me, this issue is the same as making women remove their naqab for an ID card picture or their passport photo. You should be able to ID other drivers on the road, and permitting cars with overly-tinted windows makes this impossible.