Most car windshields are made of laminated glass — two layers of glass bonded with a plastic interlayer — while ordinary side windows are tempered glass. Luxury cars increasingly use acoustic laminated glass for the side windows too, with a special sound-damping interlayer that reduces wind and road noise. Some flagships, starting with the 1991 Mercedes-Benz S-Class, have used double-pane side windows. Laminated side glass also blocks most UV light and is much harder to break through, adding security.

Types of automotive glass

Type How it’s made Typical use
Tempered Single sheet, heat-treated to shatter into small pieces Side and rear windows on most cars
Laminated Two glass sheets bonded with a PVB interlayer Windshields; side windows on luxury cars
Acoustic laminated Laminated with a sound-damping interlayer Premium side windows and windshields
Double glazed Two panes with an air gap Some flagship sedans (e.g., the W140 S-Class)

How acoustic glass works

The plastic interlayer in acoustic glass is engineered to dampen vibration at frequencies where wind noise is most noticeable. The difference is measurable, and passengers perceive it as a calmer cabin, especially at highway speeds.

Security and safety

Laminated glass holds together when broken, which:

  • Resists smash-and-grab break-ins, since the window does not simply shatter.
  • Keeps occupants inside in some crashes.
  • Blocks most UV radiation, protecting skin and interiors.

Double glazing

The W140 S-Class of 1991 introduced double-pane side windows, with an air gap that insulated against noise and prevented fogging. Read the W140 S-Class.

Glass and privacy

Rear privacy glass is tinted during manufacture. For tint rules, read window tint laws in New York and New Jersey.

Why it matters

Acoustic glass is one of several ingredients — with insulation, tires and active noise cancellation — that make luxury cabins quiet. Read active noise cancellation in cars.