Fewer air travelers will have to take off their shoes and get their carry-on bags searched at security checkpoints under a new screening policy at airports around the country.

The Transportation Security Administration (search) is giving people who set off metal detectors on their first pass through the metal detectors a second chance, after they've removed the coins or keys they think caused the alarm.

Before, setting off the metal detector meant a secondary search, which involves removing shoes and getting wanded while screeners search carry-on luggage.

Now, those who make it through the metal detectors a second time — and who haven't been flagged for extra screening — can go right on to their gate.

The change, which took effect Dec. 27, can save time and shorten lines, Yolanda Clark, TSA spokeswoman, said Thursday.

"When you go through secondary screening, you've lengthened the time you've spent by three minutes," Clark said.

One reason for the change was that people who travel infrequently weren't used to the new metal detectors that have replaced the older, less sensitive machines in use on Sept. 11, 2001, said Clark.

Typically, passengers unfamiliar with the new machines would think a penny or a sneaker wouldn't set off the alarm, only to find out that they were wrong.