Why Does the Windshield Cause Dizziness?

[CamillaAnn]

Because internal distortions in the glass cause abnormal refraction of light. Here is some relevant information about windshields: 1. Precautions: Tempered glass cannot be used for windshields. Generally, windshields are made of laminated glass, while door glass is usually cheaper tempered glass. 2. Quality Differentiation: The edges of broken low-quality glass are usually very sharp, whereas qualified glass has smoother break edges. Each piece of glass has a label in the corner containing a lot of information, such as the glass brand, production date, manufacturer, etc. China mandates 3C certification.

[Elrond]

When driving, if you notice dizziness from the windshield, it's most commonly caused by the window film. Last time I changed my heat-insulating film, I encountered this issue. The merchant explained that it was due to uneven light refraction from cheap film. Especially when driving in sunlight, the windshield can appear as if covered with a layer of grease, causing glare. In fact, national standards require that the light transmittance of front windshield film must exceed 70%, but inferior films may secretly add reflective layers, leading to dizziness. Additionally, it's worth noting that oil film on the glass surface can exacerbate this phenomenon, so remember to regularly clean it with glass cleaner. Nowadays, there are high-end films on the market with anti-glare coatings. After switching to one, I indeed felt much more comfortable, though the price is double.

[Haley]

I've researched the dizziness caused by the windshield, which is essentially an optical distortion. Although the glass is flat when it leaves the factory, if the stress distribution is uneven during installation onto the frame, tiny ripples can form after exposure to high temperatures. The most extreme case I've seen while repairing cars was a car owner who applied dark tint film and installed a dashboard sunshade, creating a buff-like reflection that was extremely dizzying. An experienced modification shop technician mentioned that windshields with larger curves are more prone to this issue, especially in sporty models with small A-pillar angles. It's recommended to use a sunshade when parking in summer, which can alleviate 80% of the dizziness. Practical tests have shown that wearing polarized glasses is also remarkably effective and much more cost-efficient than replacing the windshield.

[SanEliza]

This dizziness may result from multiple overlapping factors. The first layer is stress patterns formed during glass manufacturing, similar to the rainbow patterns seen when squeezing a plastic water bottle. The second layer is oil residue left by worn wiper blades, like applying a coat of wax to the glass. The third layer is caused by density changes in the air due to hot air from the AC vents. During our fleet's long-distance runs, we found that adjusting the AC airflow direction away from the windshield can alleviate symptoms. Additionally, check if the glass has been chipped by stones, as tiny cracks can produce diffractive glare under strong light.