A live test of a new service that automatically scans travelers' passports using computer technology debuted at the San Francisco International Airport Friday.The test of e-Passports, a collaborative effort between the U.S., Australia, New Zealand and Singapore, will run through April 15 at Terminal G at SFO, according to the U.S. Department of Homeland Security. E-Passports are smart cards that contain the holder's biographic information and a biometric identifier, in this case a digital photograph, according to the Department of Homeland Security.The test allows those entering the U.S. who have been issued e-Passports to present and scan their passports through machines that can automatically read them to check their identity, the department said.The trial will test how the use of new equipment and software affects general operations at the SFO airport terminal, according to the department. Similar tests are running concurrently at Changi Airport in Singapore and Sydney Airport in Australia.This is the second live test of e-Passports conducted between the United States, Australia and New Zealand. The goal of the test runs is to ensure that other countries that are developing or want to develop e-Passports can comply with International Civil Aviation Organization standards for implementing the system, according to the department. Previous tests of the system were held at Los Angeles International Airport and Sydney Airport.In addition to the countries in Friday's e-Passport trial, Belgium and Canada also are in the process of testing e-Passport systems. The technology has come under fire from privacy advocates who fear that governments may use the information stored in e-Passports to track everyday activities of their citizens.The Department of Homeland Security's US-VISIT initiative, which is aimed at more efficiently and safely allowing travelers to enter the U.S. from other countries, is overseeing the e-Passport test.