I have tinted windows for 25 years.
Here’s the low down. Back when the DOT was started safety glass was allot thicker then it is now the DOT decided due to the thickness, distortion, and color of the glass and laminates, that a 70% light transmission was all they would allow for a clear view. This mandated that all factory "clear glass have a 70% light transmission or less" the current quality of safety glass is allot better and thinner however the highway patrol has one of the single largest lobbies in the state and you would have to change the manufacturers law at a federal level for it to make any diff and then you would have to petition the state and so on.
In Cali you cannot legally put anything on the front 3 windows. you can even get a ticket for a visor strip depending on how the cop interprets the law it was amended to allow a strip but if the cop only looks at the first paragraph of his cheat sheet you will get a ticket for that too.
Visor law: is measured with the driver’s seat all the way back, you measure 5" from the back rest of the seat towards the steering wheel then you measure 28" up. Anything above 28" is fair game. There is no 6” or 8” rule. That’s the average size they come out to.

BTW the “%” on tint is the amount of light it lets in

On a side note 10 or 15 years ago the univ of Illinois did a test on film and discovered that a 35% film was the safest due to the amount of glare it reduced and didn’t impede the driver’s ability to see at night.

The funny thing about the tint law is that cops are trained to look thru the back window to see what you’re doing before they walk up to the car and you can black these babies out.

Hope this helps

 

SemaXD:

 

SemaXD, that pretty much sums that up, good write up!

 

when you get pulled over, just roll the windows down and say it's hot. haha

 

Out here that wont work . He will tell you to roll up your windows so he can see if they are tinted .