As you may know starting January 31, 2008 all US Citizens who enter the US by land and sea ports-of-entry when arriving from Canada, Mexico, the Caribbean and Bermuda will need to present a valid passport. In addition to the regular passport, a Passport card will be available.
U.S. citizens may begin applying in advance for the new U.S. Passport Card beginning February 1, 2008, in anticipation of land border travel document requirements. Cards will be available and mailed to applicants in spring 2008.
The passport card may not be used to travel by air. It will otherwise carry the rights and privileges of the U.S. passport book and will be adjudicated to the exact same standards. The Department of State is issuing this passport card in response to the needs of border resident communities for a less expensive and more portable alternative to the traditional passport book. The card will have the same validity period as a passport book: 10 years for an adult, five for children 15 and younger.