NZTA LEGAL REQUIREMENTS
On this page are the legal requirements for window overlays
Window film overlays and other allowable modifications
The most common modification to windows is the fitting of tinted or advertising window film overlays. The legal requirements for window film overlays balance road safety issues with the desire of some vehicle owners to put tinted films, advertising or other artwork on their vehicle windows.
The term ‘overlay’ generally refers to self-adhesive or clinging film that is applied to larger areas, or the whole of a window. It can include clear film, tinted film and advertising film. Smaller applications are generally referred to as stickers.
There are restrictions on overlays because they can reduce the driver’s ability to clearly see the road, other road users and potential obstructions.
VLT means ‘visible light transmittance’ and is the amount of ‘visible’ light that passes through a vehicle’s windscreen and windows. A clear windscreen has a VLT of approximately 85%, although the VLT can be a low as 70%. If an overlay is applied to a window, the overall VLT is measured as the amount of light passing through both the glass and the overlay. This means that if a tinted film overlay of 35% VLT is applied to a front side window that already has 70% VLT, the overall VLT will be well below 35%.
The overall VLT is checked by using a calibrated VLT meter. Most vehicle testing stations have a VLT meter so you should see them or a reputable window film installer if you would like to have the VLT of your tinted windows measured (get written confirmation of the overall VLT from the installer if you need to). Note that VLT measurements are only relevant to transparent (clear or tinted) overlays. VLT is not an appropriate measurement for non-transparent overlays, such as printed or perforated advertising film.
Where can I have transparent film overlays applied?
The only overlays allowed on windscreens are:
- anti-glare bands that extend no lower than the bottom of the sun visors when folded against the windscreen (no print allowed below 100mm from the top of the windscreen)
- stone guards overlay on goods vehicles and buses fitted no higher than the top of the steering wheel.
Front side windows
‘Front side windows’ means the windows on either side of the driver’s seat. Front side windows fitted with transparent overlays must have an overall VLT of at least 35%.
Rear windows (windows behind the driver’s seat)
A transparent overlay applied to a rear window of a car (sedan, station wagon, hatchback, sports car or convertible) must have an overall VLT of at least 35%.
An overlay fitted to a rear window of any other vehicle, including a stretch limousine and body transfer vehicle, may be of any tint level.
Any vehicle with an overlay applied to a rear window must have an external rear view mirror on each side.