The system came to the Robert L. Stanfield International Airport in Halifax, Nova Scotia, earlier this week. It will open at airports in Calgary, Alberta; Edmonton, Alberta; and Winnipeg, Manitoba in the coming months. The Nexus program already operates for more than 130,000 enrolled members at airports in Vancouver, Toronto, Montreal and Ottawa.

Canadian border service authorities and the Homeland Security Department's Customs and Border Patrol co-sponsor the program. Pre-enrolled travelers undergo a security check and are issued secure identification cards containing an iris scan biometric. The members' irises are scanned again at the airports to verify that they match information on the card.

The DHS has designated Nexus identification cards as acceptable alternatives to passports under the department's upcoming Western Hemisphere Travel Initiative. Under the initiative, travelers from the U.S., Canada and Mexico will need to show passports or other specific approved identification cards at the land borders. Currently, thousands of documents are acceptable to indicate identity at the borders.

The Nexus card initially was set up to prescreen travelers, such as exporters and importers, who frequently cross the borders, in order to speed them through customs and immigration clearances in dedicated lanes. Washington Technology