As of January 31, 2008, new travel document requirements go into effect for U.S., Canadian and Bermudian citizens entering the United States at land or sea ports-of-entry. They must present proof of citizenship, such as a birth certification, and proof of identity (e.g., a driver's license) to the U.S. Customs and Border Protection (CBP) officer. An oral declaration of citizenship will no longer be sufficient.
For children ages 18 years and under, they will be required only to present proof of citizenship and not the additional proof of identity. Passport cards will continue to be valid for cross-border travel (for departure from and entry to the United States through land and sea ports-of-entry between the United States and Mexico, Canada, the Caribbean and Bermuda.) Passport cards, unlike passport books, are valid without signature but are not globally interoperable international travel documents.