Permission to cross the border: effective policy reduces high-risk drinking by Marines

At a Marine Corps base near the Mexican border, off-base alcohol- related incidents increased when serving alcohol to personnel under age 21 on the base was no longer permitted. The bars across the Mexican border, where the legal drinking age is 18, are an important source of alcohol for the Marine enlisted men. To reduce cross-border drinking, the base command instituted a "chit" system requiring enlisted men to receive written permission to cross the border. This study evaluates the effectiveness of that policy.

Breath test surveys of American youths returning from Tijuana to San Diego County provided counts and blood alcohol concentration (BAC) of marines returning from a night of drinking in Mexico before and after the "chit" policy. Comparison counts and breath tests for Navy personnel from a San Diego base not affected by the "chit" policy were available for the same time periods.

The number of underage marines returning from Mexican bars was reduced by 78%, and of those the number with illegal (> or = .08%) BACs was reduced by 84%. There was no significant change for the comparison group of sailors.

It appears that the "chit" policy was highly effective at least for the 6-month post-period covered by this study. This apparent success influenced the implementation of the "chit" policy on all naval facilities in the San Diego area.