Our car experts choose every product we feature. We may earn money from the links on this page.

Many late-model vehicles have laminated glass on side windows, which won't yield to tools designed to break them.

Here's something you may not know: Every window in your car doesn't necessarily have tempered glass, the kind that turns into a pile of small harmless chunks in case of breakage. Instead, some of your windows, nearly always at the side and occasionally at the rear, may be made of laminated glass.

Why should you care? Mainly because, in the extremely unlikely event of trying to escape a car that's on fire or sinking underwater, those windows could prove unbreakable and could trap you inside.

A new AAA report lists 21 pages' worth of cars and trucks that have laminated side or rear glass that, during the organization's tests, were impenetrable by consumer glass-breaking tools. Some of these vehicles date back to the 1970s, although the majority were built within the past five to 10 years. One in three 2018 models have such glass, AAA claims, which means that if you are trapped in a vehicle and the glass is your only escape route, surviving may depend on knowing exactly which windows are most easily broken.

In these admittedly unusual worst-case scenarios, using a spring-loaded punch tool—not a hammer, as it's nearly impossible to apply enough force against a window while underwater—will cause tempered glass to break. They won't work against laminated glass. The good news? Less than one half of 1 percent of all crashes involve the vehicle becoming submerged in water, according to John Paul, public safety manager for AAA Northeast. Despite the horror of being trapped inside a car, most drivers don't carry such tools. Given the abundant risks of driving and the nearly infinite variables of a crash, laminated glass is more likely to reduce injuries and potentially save your life in a bad accident.

Laminated side and rear glass aren't new, although automakers have been increasingly fitting them to comply with a rule the National Highway Traffic Safety Administration (NHTSA) passed in 2011. It's known as Ejection Mitigation, and it requires a combination of side airbag curtains and stronger windows to keep occupants inside the car during a rollover. In fatality studies, NHTSA said in 2011 that passengers are 64 percent less likely to die if they aren't completely ejected in a crash. While unbelted passengers comprise the majority of such deaths, even partial ejections can occur and cause severe injuries, or death, for those wearing seatbelts.

Government tests involve demonstrating that side windows are strong enough to cause a maximum allowable deflection at specific speeds and forces designed to simulate a person's head or shoulders impacting the glass.

Laminated glass isn't the same as tempered glass, also known as safety glass. Tempered glass shatters into thousands of tiny pieces upon impact to prevent deep cuts. Laminated windows work like windshield glass in that they remain in one solid piece during minor impacts with only cracks and deflections. That's because there is a plastic laminate sandwiched between two pieces of glass. That's why the windshield tends to peel off the frame after stronger impacts. The same principles apply to laminated side glass.

There's a benefit to laminated glass aside from keeping heads, arms, and legs inside the vehicle. It's inherently quieter than standard tempered glass, so it becomes an easier, cost-effective way for automakers to reduce noise without installing foam and other sound-deadening material within the vehicle chassis.

Laminated windows also make it much tougher for car thieves to commit "smash and grab" crimes. The lesson? Know your windows, prepare an escape plan, and don't worry all that much.