Police in Mexico City began using breathalyzers to test for drunk drivers in September, and have stepped up checkpoints during the holiday season. But New YearÂ’s Eve they will put their analyzers away, leaving the roads open to everyone, drunk or not. Their reasoning is that both Christmas Eve and New YearÂ’s Eve are family celebrations, and many celebrants spend the night with their hosts, but this logic may well suggest that visitors should stay off the streets on New YearÂ’s Eve, or travel as little as possible during their celebrations.