U.S. Auto Insurance Companies do not extend coverage into Mexico. The only exception is physical damage (comprehensive and collision) coverage within 15-50 miles of the border, depending on the specific carrier. Your U.S. State issued liability auto insurance coverage stops at the Mexican border because of one reason. Mexico operates under Constitutional Law as opposed to Precedent Law in the United States...

...Word of advise, when traveling south of the border with a vehicle, get Online Mexican Travel Insurance from one of several well established carriers. Most of the Online Mexican Travel Insurance brokers offer the same carriers such as GNP (oldest), ACE, and GE and everything you need to quote, bind and issue coverage is readily available on the website.
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