Officials say lenses atop stoplights are aimed at improving traffic flow.

 Motorists may have noticed new cameras popping up on more intersections across Southwest Florida these days.

A few in Manatee County are part of a pilot program to catch people who run red lights.

But the majority of the new cameras don't take photos of traffic or motorists; instead, they just monitor traffic and change red lights to green when cars approach.

The gadgets, called video vehicle detection cameras, tell stoplights that a car is approaching and should change color. They're a cheaper, longer-lasting method of controlling signal lights than the underground method.

In the past two years, more counties have begun installing the cameras on traffic signals to replace in-the-road sensors, which are sometimes destroyed when construction crews do road work.

Manatee County has nine intersections with cameras, including University Parkway and Lockwood Ridge Road on the Sarasota County line.

Replacing just one of the underground sensors -- also known as loops -- can cost about $750.

Some intersections use as many as 20 loops, for a cost of $15,000.

At most, eight $1,500 cameras are used at an intersection, for a total of $12,000.

Many communities around the country waited see how well the technology worked, but Sarasota was among the first counties to jump on the technology almost 10 years ago, about the same time the cameras were developed.

Manatee and Charlotte counties began using the cameras almost two years ago and have added more in the past year.

"You are going to be seeing these more and more, but people should not think these are the red-light cameras," said Aaron Burkett, a Manatee County signal technician.

A SENSE FOR TRAFFIC

How they work
The camera takes a low-resolution image made up of colored pixels. When the car enters the field of vision, the camera detects a change in the color of pixels and assumes a car has approached. The traffic signal is told to change.

The costs at one intersection
Ground sensors: Up to 20 per intersection, total cost $15,000.

Cameras: Up to 8 per intersection, total cost $12,000.

The benefits of cameras
Above ground, no digging, not destroyed by roadwork.

Highly reliable.

Can count traffic.

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