A new remote sensor for auto emissions being tested in the Washington, D.C., area could be either a tool for Big Brother or a blessing in disguise.

Supporters of the sensor call it a revolution in environmental safeguards, but opponents fear the radar equipment is reducing personal freedom from government surveillance.

The laser sensor, which clocks cars' emissions to determine if they are in compliance with state standards, takes a photo image of violators' license plates, similar to the controversial cameras already used in some areas to bust speeders and traffic light violators.

The state of Virginia is planning a pilot program at two remote stations along the roadways in the Washington area to test the technology and how it would be used. If the test, planned for 2003, is successful, a full program may be implemented in which the drivers of noxious cars would be notified by mail that their automobiles need to be fixed.

"The least obtrusive way to maintain air quality, that's our focus," said Bill Hayden, a spokesperson for the Virginia Department of Environmental Quality.

But opponents of the remote emissions tests say they are just another way for the government to spy on its citizens, this time using the environment to garner support for more cameras on the nation's roadways.

"They're just expanding the same photo enforcement technology and they're going to keep expanding into more and more intrusive places," said Richard Diamond, a spokesman for House Majority Leader Dick Armey, who has been a vocal opponent of the red light cameras used in the D.C. suburbs of Virginia.

True, the technology is not new. Developed by Donald Stedman and Gary Bishop of the University of Denver in the early 1990's, remote sensing has been tested and utilized in cities throughout North America, including California, which battles one of the worst air pollution problems in the U.S.

Still the use of detection technology, including red light and speed cameras, is a source of apoplexy for civil libertarians, who are winning lawsuits against the cameras.

At least three courts have ruled against the use of such cameras by municipalities in recent months. This week, a judge in Colorado shut down the use of photo radar cameras in Denver, saying the program violated both state and local laws. The judge dismissed the tickets of four defendants challenging the system and the city was forced to turn off the cameras.

"The government should not be in the business of tracking its citizens unless they are committing a crime," Diamond said in support of the ruling.

However, proponents of the cameras say traffic violators are committing crimes.

"If you are doing something that is hurtful to others, then the government is supposed to track you and it's legitimate," said Kenneth Green, chief scientist for the free-market Reason Public Policy Institute. "If you are driving a polluting vehicle then you are doing something wrong."

Green said the remote sensor will only track cars that are not in compliance with the law, creating the possibility that laborious and expensive state inspections required of every driver could come to an end.

That could be wishful thinking, however. Jim Harper, a privacy attorney and editor of Privacilla.org, said that adding the new sensors probably would not reduce government enforcement by other means.

"One side of this may be that they will use this to replace the inspections – you might reduce the burden for citizens. However, the chance that government would actually give up their inspections is slight and this could just be adding another layer of government."

But Harper says if the government has probable cause — like emissions violations — to take a photo of one's license plate it is not a violation of privacy rights, as long as there is "a statutory and constitutional guarantee" that citizens' information would be used for nothing other keeping a statistical record of pollution in the area and to notify the driver of their car's violations.

Diamond disagrees, and as a Virginia resident has had the personal experience to make his case.

"I got a survey from the city of Alexandria, who said 'we know that you were traveling at this time of the day and we wanted to ask you some questions,' about an area construction project," he said.

Diamond said the information was taken from a traffic photo camera, proving his point that the problem with the cameras is that they allow the government to track citizens' movements.

The Texas American Civil Liberties Union concurs. That group called attention to a survey issued by the Texas Transportation Institute last summer based on the information gleaned by videotaped license plates at five spots along the Texas borders. ACLU activists say Americans should be protected from such intrusions.

"One thing we have in this country is freedom of movement without being filmed and processed the entire time," Joann Bell, director of ACLU Oklahoma Foundation, said after the survey's release.