Data in this section are from multiple sources that use different time series. Total international travel data cited here include both same-day and overnight trips, and are derived from travel surveys conducted by Canada and Mexico as well as regulatory data from the U.S. Immigration and Naturalization Service.
Overnight travel data are available for 2000 from the International Trade Administration (ITA), U.S. Department of Commerce. However same-day travel data, and consequently total international travel data, are only available for 1999. Therefore, this report uses data for both years.
The Canadian and Mexican travel survey data, as well as data released by ITA, are based on travel by residents of each country to the other two countries. Therefore, these data do not capture the entry of all persons into the United States along the U.S.-Canadian or U.S.-Mexican borders.
This report also uses border-crossing data from the U.S. Customs Service, which measure the entry of all persons into the United States along the north and south borders, but without the travel and trip characteristics provided by the Canadian and Mexican travel survey data. Border-crossing data indicate a total of 388 million entries in 1999, and count any person entering the United States, including U.S., Canadian, and Mexican residents as well as residents of other countries. Because of this distinction, the travel survey data will not correspond to the border-crossing data. Both data sources are used in this discussion, with travel survey data presented to assess modal choice and trip purposes and border-crossing data to illustrate activity at particular border-crossing infrastructure points.