It's not legal to have any tint, (even 70%) below the VS1 line. A lot of people make the mistake thinking they can put 70%/80%/90% on the entire windshield but this isn't true, the way the law is written your front windshield must have a visible light transmission rate of 70% or more but with absolutely nothing on it straight from the factory most windshield will be in the 75%-80% range. You might get away with a 95% tint on the windshield but just barely.

Now in reality, I have 90% tint on my front windshield and unless you look for it you can't see it and yes it does help a lot but I also drive a a honda crv or camry, if I drove something like a corvette, camaro, or busted 90s civic with a fart can exhaust I feel like police might give me a harder time.

If you look around tons of people are rolling around with 20% tint or below and they seem to do just fine, I feel like if you get pulled over for going 10mph over or a busted taillight, keep your hands on the wheel until told otherwise, turn the overhead light on before they approach if it's dark, and just be polite most cops aren't going to care about a 90% or even 80% windshield tint.

Now if you're driving like a maniac or give them the "make it quick, I'm late for work" attitude yea they'll cite you for it.