Stone chips on vehicle windscreens could potentially be dangerous – depending on their size and location. Imagine for example, having something like this in the centre of your field of vision.
NOT a picture of a chip on my car’s windscreen
Unlike this one, the chip on my windscreen is very small and hard to see, so I visited the NZTA website to find the details of the rulings. Here’s what I’ve found so far:
Land Transport Rule
Glazing, Windscreen Wipe and Wash, and Mirrors 1999
2.2(1) (d) a windscreen must not have scratches or other defects that unreasonably impair vision through the glazing or compromise the strength of the glazing.
The only time you see the chip on my windscreen is when searching for it, and focussing up close on the glass (not something you do when driving). It does not unreasonably impair vision and while not an engineer, I can’t imagine that it compromises the strength of the glazing either.
Light Vehicle Repair Certification
Figure 3-1-3. Types and maximum sizes of windscreen damage
It seems that I have what is called a “Star” chip on my windscreen. In my case this is a shallow chip with equally shallow ‘arms’ of the star, that measure 20mm across at their widest point.
If I understand this correctly, this chip falls well within the stated acceptable limits.
The next step is to write to the NZTA to see if they can point me to any other pages, in case I have misread or misinterpreted their ruling.
Windscreens 