Some Utah Valley drivers will probably feel Smog Dog's bite by the end of the month, but it won't be too painful at first.

The Utah County Commission approved an ordinance this week setting up what amounts to environmental PhotoCop. Officials intended to get the voluntary phase of the program started April 1. Changes in the ordinance's language and construction delays at the county's vehicle testing center, however, set the date back.The county's Bureau of Air Quality will place Smog Dog - a roadside vehicle emissions testing device - at various locations throughout the valley. The unit uses an infrared beam to single out grossly polluting cars while a camera snaps a photo of their license plates. It automatically measures the carbon monoxide output and catalogs the data in the computer.

Owners of cars putting out 5 percent or more CO will receive a letter from the county inviting them to its Spanish Fork testing center starting in late May or early June. Because the program is voluntary, at least until Aug. 1, officials don't quite know how they'll entice people in.

"I haven't figured it out yet," said Terry Beebe, manager of the county Bureau of Air Quality.

Drivers will likely be offered a free emissions test. Vehicles that pass and are within two months of registration renewal would receive an emissions certificate.

The program is essential to the county's effort to improve and maintain air quality as well as to comply with federal standards. Officials believe the data collected from Smog Dog over the next 18 months will prove to the U.S. Environmental Protection Agency that remote sensing is an effective weapon in the battle against pollution.

"I'm not going to put a program in place that EPA is not going to sign off on," said Utah County Commissioner Jerry Grover.

Smog Dog would complement the county's existing annual emissions inspection and maintenance program. And with EPA approval it would keep the county from having to centralize the I/M program, taking it out of the hands of local gas stations and shops.

Cars identified as "super clean," those with two CO readings of zero in 12 months, would be exempt from the annual emissions test.

A consultant will analyze the information Smog Dog collects before the county pleads its case before the EPA. Grover figures the county will need to test as many as 2,000 cars to have a statistically valid sample.

"I want it to be based on science, not politics," he said, adding he's fairly confident the county will be allowed a permanent remote sensing program in some form.

After Aug. 1, drivers who receive letters from the county will be required to bring their vehicles to the testing center. Owners would have to pay for any repairs needed to make the car "clean."

Those who ignore the notice could be charged with a Class B misdemeanor, punishable by up to six months in jail and/or up to a $1,000 fine, according to the ordinance. Beebe said the county also may withhold a car owner's registration.