Does your car have tinted windows? Has your GPS ever led you astray? If the answer to both questions in yes, the problem is not with your Garmin or Google's navigation app. It is most likely the material used in your car's window tint.
Recently, I began posting to the Examiner's Auto and Motorcycle section, and while speaking with the owners of a local custom auto detail shop, we learned of this quirky little glitch. Geoffrey Blair, co-owner of The Car Guys in Millersville, Maryland told us that metallic tints can cause your GPS to be off course by a few hundred feet.
This explains how someone can be driving along Thames Street in Fells Point looking to make a right onto S. Ann. Trusting in Google, he/she is oblivious to the parking lot sitting across from the Cats Eye Pub, hangs a right about 65 feet before S. Ann, and drives into the harbor. Sadly, we can imagine this happening.
If you have after-market tinted windows, don't panic. According to Geoffery it is only tints that use metal particles embedded in the film that play havoc with GPS signals. Other tints, such as those that contain ceramic particles or carbon based films have no adverse effects on GPS systems. When we asked Geoffrey why people would use a metallic film, his answer was simple; cost. Metallic films are cheaper.
Most of the metallic films on the market these days seem to be DIY products. It is hard to ascertain from a web search which tints contain metal, so our best suggestion is to ask someone at Auto Zone or Advanced Auto Parts if you are thinking about applying your own window tint. Another suggestion is not to purchase the least expensive tint you see. These are the products most likely to contain metal.
Perhaps the best alternative is to have a professional tint your car's windows. Most detail and tint shops stay away from metallic tints these days. There are a few shops who may offer them as a cost convenience to customers, so be specific as to the material you want the shop to use on your vehicle before authorizing any work. The Car Guys offers only carbon tints, thus eliminating the possibility of GPS interference. If you are thinking about having your windows tinted, do your research first.
Also, check state laws. In Maryland, the Visible Light Transmission percentage(VLT%) is 35%. This basically is the percentage of effective light allowed into the vehicle through a combination of window and tint covering. Detail and tint shops can give you further guidance if you need it. If you are reading this from outside the state of Maryland, use this link to find the tint laws for your state.