Automotive tinting specifics
OEM Glass
OEM glass is the original-equipment-manufacturer glass installed by the vehicle maker; it already has some VLT reduction and UV rejection before any aftermarket film is added.
OEM glass typically has 75–85% VLT on the windscreen (depending on whether it is laminated and what the green tint level is). On side and rear glass, OEM "privacy glass" can already be 30–60% VLT before any aftermarket film.
When measuring for compliance, the LTA's 70% windscreen rule applies to the FINAL combined VLT — glass plus film. A 75% VLT windscreen with a 90% VLT film yields about 68% measured, which fails. The same windscreen with a 92% VLT film yields 69% — borderline.
Reputable workshops measure your OEM glass VLT before quoting film options to avoid surprises at compliance check.