Will Body Scanners Make Lines Longer?

Ever since the (fortunately) failed terrorist attack on Northwest Airlines 253 from Amsterdam to Detroit, discussion on body imaging scanners in airports have flared up, as some believe that if these machines were in place, Umar Farouk Abdulmutallab wouldn't have made it onboard the flight in the first place.

Not surprisingly, rhetoric against the scanners increased as well. Many have expressed privacy concerns as the images that are generated by the machines look under one's clothes:

Found on tsa.gov.

TSA has responded to these concerns by noting that passengers will never see the agent who is looking at the images, and that the body scan images cannot be saved.

But some airport managers and industry trade groups have expressed some different concerns - that the new scanners will make checkpoints more congested. One reason is that the machines are bulkier than metal detectors, and in some security checkpoints space already comes at a premium. Another reason for concern is that it takes a few seconds longer to go through one compared to a metal detector. At a busy airport with thousands of passengers, that time can add up. The TSA says, however, that since one major bottleneck at security is placing bags on x-ray machine belts, which are before the detectors, there won't be a huge affect on time.

Regardless, TSA is moving ahead with installations, with 950 scanners coming in the next two years, mainly used for primary screening. Right now, the machines are used as an alternative to a pat-down in 13 airports, and used for primary screening at six others.