Speed cameras on U.S. highways? - CNN.com
Speed cameras on U.S. highways?
(AOL Autos) -- You may already have seen an ominous looking radar and camera perched atop a traffic light in your neighborhood. And almost all drivers have seen a patrol car cruising a freeway looking for speeders, or a law-enforcement officer standing at the side of a road wielding a radar gun.

But most have yet to see a freeway speed camera, which are common in Europe but currently are operated in just two U.S. states.

Opponents and backers of speed cameras both suggest that eventually speed cameras will become the norm on U.S. freeways. But just how likely is a nationwide roll-out? And what factors stand in the way? We take a look.

Sponsoring legislation in Maryland

Maryland Gov. Martin O'Malley signed into law on May 19 Senate Bill 277, allowing the use of speed cameras in highway work zones and within a half-mile radius of schools, which means that they can be placed on freeways under these conditions.

Maryland is only the second state behind Arizona to codify the use of freeway speed cameras into law. Hawaii piloted a program but dropped it, and similar programs near San Jose, California, and in southern Florida were dismantled after they were found to be operating outside of state law. Maryland's law takes effect on October 1.

"Maryland is in a unique position," said Sean Adamec, the governor's spokesman said.