Window tint darkness is measured in VLT — visible light transmission — the percentage of light that passes through the glass. A higher VLT number means a lighter, more transparent tint; a lower number means darker. New Jersey's rules are more conservative than many drivers expect, and they differ by window position.
Front side windows and the windshield both have to let in more than 70% of light under New Jersey law. In practice, that limits front glass to the lightest ceramic IR films — the kind built to cut heat and UV without darkening the view, not the deeper shades most people picture when they think of "window tint."
Rear side windows and the rear windshield are not subject to that same restriction — New Jersey allows any darkness back there, down to the deepest 5% VLT films. That is why a lot of NJ vehicles run a noticeably darker rear cabin than front.
Reflective or mirrored tint is prohibited statewide, regardless of which window it is on. This is a common point of confusion for drivers coming from states with different rules, or comparing notes with out-of-state shops.
Illegal tint is something New Jersey's vehicle inspection can flag, and it is also something an officer can cite during a traffic stop independent of inspection. The safest approach is to confirm the legal VLT for each window position before the film goes on, not after — a shop working from New Jersey's actual limits will spec the front windows and windshield differently from the rear glass by default.
This is also why a full-vehicle tint quote is never really "pick one darkness for everything." At HAUT, every job accounts for New Jersey's per-window limits from the start, so the front glass stays street-legal while the rear cabin can go as dark as the client wants.