Road Rules: How dark is too dark for tinted car windows?


Question: I’m pretty sure that Washington has a regulation for how dark front passenger and driver side windows can be tinted. If so, why do I see so many vehicles with windows that are almost totally blacked out? Why is it not enforced since it is definitely a safety issue?

Answer: Window tinting is one of those cases where if a little is good, more is not better. And let me explain what I mean by

People get their windows tinted for a variety of reasons, but when we’re talking about any modification to a vehicle, safety has to be the primary measurement determining what’s better. Dark windows might look more stylish, keep the interior of your car cooler when it’s parked in the sun, and increase privacy, but none of those things positively influence the core function of driving: getting safely to your destination.

If you were to research window tinting online, you’d find information mostly from two sources: Companies that tint windows, and lawyers. The tint companies promote the benefits of tinted windows, and the lawyers look for clients who have been in a collision involving another car with windows so dark it impaired the other driver’s vision.

Based on those two sources, it’s obvious that at some point window tint moves from a benefit to a liability. When is window tint too dark? There are two answers:

It’s too dark when it violates the law. Tint is measured as a percentage of how much light is allowed through the glass. A lower percentage equates to darker windows.

In Washington, the maximum amount of tint allowed on all windows except the windshield is 24 percent. You’re not allowed to tint the windshield (except for the top 6 inches). While following this rule can prevent a ticket, it may not be the best standard for safety. Plus, the rules change from state to state. Many states limit window tint to 35 percent, and some set the limit at 50 and even 70 percent.

Here’s the other answer: It’s too dark when it diminishes your vision or you’re unable to make eye contact with other people on the road.

Researchers have found that your visual acuity and depth perception are affected when windows are tinted to around 65 percent. At that level the impact is minimal for most people, but in less-than-ideal driving conditions it can make a difference, and we have plenty of non-ideal driving conditions in Washington.

Age matters too; another study found that while younger drivers could see sufficiently at night with 35 percent tint, older drivers experience a “significant drop” in their vision at that level.

Some people ignore the law, but it might not be as many people as you think. I conducted a non-scientific study of 100 cars while on a walk through town, and saw only one car with windows so dark I couldn’t make eye contact with the driver, along with two that were pretty dark but probably legal. I’m not an expert at estimating window tint, but if you can’t see the person in the car, it’s definitely too dark.

I’ve talked with officers who enforce the law, so I know it happens, but maybe not as much as you’d like.

Dark window tint doesn’t demand the same level of concern as impaired driving, distraction and speeding, but even the smaller things add up and contribute to risk.

And as important as enforcement is, we can’t rely solely on police for safety on our roads. It takes all of us engaging in safe driving practices, and operating safe cars.

Doug Dahl is a manager with the Washington Traffic Safety Commission, Region 11 and publishes


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