I agree to disagree; there must be some local and even temporary price inflation where federal highway works may be in progress.
Daniel, yes, there is a slight "inflationary" effect in some zones. For a time I worked for a factory in 'Ciudad Juarez' , factories have slightly higher wages : 300 to 450 USD per month, the same happens with some factories with a modicum level of technology in the rest of the country.
Yet, the overal effect in the Mexican economy is negligible ( Juarez which is the city with most American factories has less than 3 million people, compare that to Mexico city's whooping 21 million).
By what I've heard few people there think NAFTA had a positive effect ( how else to explain the massive exodus of Mexicans into the US after NAFTA came into effect).