Portal surveys, defined as assessments occurring proximal to the entry point to a high-risk locale and immediately on exit, can be used in different settings to measure characteristics and behavior of attendees at an event of interest. This methodology has been developed to assess alcohol and other drug (AOD) use at specific events and has included measuring intentions to use collected at entry and reported use on exit, as well as chemical tests for AOD consumption at both entrance and exit. Recent applications of the portal survey procedure to electronic music dance events that occur in established venues (e.g., bars or nightclubs) are discussed.

On a typical weekend night between 12:00 a.m. and 4:00 a.m., about 4 thousand Americans 25 or younger cross back into the United States from a night in Tijuana, Mexico, clubs. More than 40% of the drinkers return the next morning with an illegal blood-alcohol concentration (.08 or higher). To study this phenomenon and to provide data with which to evaluate the community effort in San Diego County, a border research effort involving two separate surveys of individuals entering and leaving Mexico was established in June 1997. This article briefly reviews past roadside survey studies and reports on the survey methods developed to conduct these surveys and the procedure required to analyze the data collected.

Several thousand young Americans visit the bars in Tijuana, Mexico, each weekend night, raising concerns on both sides of the border. Measures implemented in San Diego, California, and Tijuana have successfully reduced the number of American visitors to Mexican bars. Although San Diego policies have been well-documented, this is the first article on investigation of measures enacted south of the border. Information on Tijuana alcohol policies was obtained from a survey of 29-36 bars from 1997 to 1999. The Tijuana police provided data on Americans arrested in Tijuana from 1998 to 1999. Our study found alcohol regulations are poorly enforced in Tijuana, suggesting that regulatory agencies are captured by bar owners. However, such a capture may be weakening. The importance of identifying and supporting Mexican interest groups, as opposed to the bar owners, as a mechanism to impede the capture of Tijuana's regulatory agencies is discussed. The number of Americans involved in alcohol-related crimes in Tijuana sharply decreased over time. However, such a success is largely related to the success of the San Diego efforts in reducing the number of American visitors to Tijuana. Also, by demonstrating the racial/ethnic heterogeneity of American visitors to Tijuana bars, our study points out the need for prevention policies designed north of the border to take such heterogeneity into account.