The four-inch rule and the AS-1 line
California permits tinting the top four inches of the windshield. In practice the reference used is the AS-1 line — a small marking on the glass, usually near the top on both sides, placed there by the manufacturer.
Look for it: it is a short line or the letters "AS-1" etched or printed in the frit band. Tint above it is fine, tint below it is not.
What it is actually good for
The sun in the valley sits low and directly ahead on east-west commutes at both ends of the day, and a brow strip catches exactly the band of sky that a visor is too far back to block.
It is genuinely useful on Highway 50 and the Capital City Freeway at either end of the day, and it is one of the cheapest comfort additions there is.
Colours and reflectivity
Red and amber tints are not permitted on any window in California, and reflective or mirrored films are separately restricted. A neutral smoke strip is the safe choice.
And a strip does not license anything below it. The rest of the windshield stays untinted.
Need this done rather than explained? There is no shop to drive to. We come to wherever your car already is — your driveway, your workplace car park, an apartment lot, or the side of the road it stopped on — anywhere in greater Sacramento, with no call-out fee and no mileage charge. Give us the year, make and model and you will have a firm price before the call ends.