As the idea of red-light cameras arises in Nassau County, the devices have made New York City streets safer, some say, but in other parts of the country they have been challenged as unconstitutional and invasive.More than 2.6 million summonses have been issued in New York City through 2005 since the program's inception in 1993. One hundred cameras now monitor city intersections."In New York City, red light cameras have been proven to reduce red light running and the injuries and fatalities that red light running often causes," said Paul Steely White, executive director of Transportation Alternatives, a NYC-area nonprofit citizens group working for better bicycling, walking and public transit.Studies have shown a 40-percent drop in the total number of incidents of motorists going through red lights at the locations where cameras have been installed. That means fewer accidents, making New York City safer for pedestrians and other motorists, according to the city Department of Transportation.In addition to reducing red light violations, cameras have been shown to reduce intersection crashes, according to the Insurance Institute for Highway Safety in Arlington, Va. In Oxnard, Calif., significant citywide crash reductions followed the introduction of red light cameras, and injury crashes at intersections with traffic signals were reduced by 29 percent.But some advocates have said the cameras are unconstitutional because they violate due process by targeting the owner of the car not the driver. They also have been criticized for generating revenue instead of enhancing safety. Some cities have stopped using the cameras, and New Jersey bans them altogether.The issue surfaced in Nassau about five weeks ago, when County Executive Thomas Suozzi identified dangerous intersections he said need the red-light cameras led by Old Country Road and Merrick Avenue in Westbury. On Friday, Suozzi said "there is no doubt that these cameras would save lives and reduce injuries."State law, however, allows only cities with a population of at least one million to have the cameras as a demonstration program. Only New York City meets that criterion. There is some doubt that the State Legislature will give the approval needed for Suozzi's request to place the cameras at 50 intersections -- or even one -- but Suozzi already has overcome one hurdle. He has convinced opponents in the county legislature to support his proposal and send a "home rule" message to Albany backing it.The most dangerous intersection highlighted by Suozzi has had 382 crashes over the past five years, and seven others on Old Country Road are almost as bad.Robert Sinclair Jr., spokesman for American Automobile Association of New York, said such cameras should be installed "as a last resort.""These cameras need to be put up as a means of achieving safety," Sinclair said. "There are things that should be tried before you get to red light cameras. Many major intersections they are talking about placing them already have problems."The American Civil Liberties Union does not oppose the use of such cameras for enforcing traffic violations, provided that the cameras capture only those images that are necessary to enforce the traffic laws. However, some are concerned that the data collected by these cameras will be used for purposes other than tracking reckless drivers, according to Jay Stanley, privacy expert with the ACLU in Washington, D.C.He also said that the issue of automated law enforcement must be examined."What about extenuating circumstances?" Stanley said. "You don't have the judgment of a human being. For example, what if the driver has a child having a severe asthma attack in the backseat?"The Michigan attorney general ruled earlier this year that cameras cannot be used to ticket drivers. Only police officers who witness violations can write tickets, he ruled. In Minnesota, the Supreme Court there outlawed them last month, saying they violate uniformity of traffic laws.And questions have been raised "whether the cameras are put into place for safety reasons or revenue generation," Stanley said. "In some cases a private corporation installed the cameras ... and a private corporation got a cut of each ticket revenue."In New York City, employees there review the film and certify tickets, staff a Help Center and provide adjudication. More than $103 million has been spent on the program since its inception in 1993 until April 2007, according to city Department of Transportation officials. The city has received more than $148 million in revenue in that same time.There are 100 intersections in the city that are watched by four cameras each. They photograph the rear of a vehicle and are situated approximately fifty to one hundred feet back from the stop-line. This results in a photo which shows the vehicle, the intersection, and the traffic signal all in one frame.When a vehicle runs through a red light, sensors embedded in the roadway trigger the camera, which takes a sequence of photographs of the rear of the car. The initial photos show the vehicle before the stop-bar and the subsequent photos show the vehicle past the stop-bar.The license plate photos are sent on a tape to the New York State Department of Motor Vehicles in Albany, which returns the tape with vehicle registrations and descriptions.Officials said the quality of the program is seen in how few challenge the photos and in how many of those challenges are upheld. In 2005, for instance, only 2.8 percent of those ticketed requested a hearing, and of them, 86 percent were upheld.As for legal challenges, such as the one that got red light cameras banned in Minnesota, New York City DOT spokesman Chris Gilbride said "there have been no lawsuits against us."Red light cameras have also been used in Albuquerque, Atlanta, Baltimore, Chicago, Denver, Houston, Los Angeles, Philadelphia, Phoenix, San Diego, San Francisco, Seattle, and Washington, D.C. plus many smaller communities, according to the Insurance Institute for Highway Safety.Russ Rader, a spokesman for the institute, said such cameras do not violate privacy rights."By obtaining a license, a motorist agrees to abide by certain rules, such as to obey traffic signals," according to an institute report. "Neither the law nor common sense suggests drivers should not be observed on the road or have their violations documented."White, with Transportation Alternatives, also noted that New York City cameras "only take photos of license plates not individuals and the cameras only take photos of license plates if a violation is taking place."A spokesman for Suffolk County said there are no plans to pursue red light cameras there.Still, in a world where an E-ZPass can track a motorist's movements, surveillance cameras can videotape passersby without their knowledge and Internet usage may be monitored from afar, cameras at red lights may be yet another invasion on privacy, experts say."One of the problems with red light cameras is what kind of rules are in place for the information captured ... Who has access? Are they going to limit it to photo enforcement of traffic laws or more of an underlying surveillance?" said Paul Stephens, policy analyst with The Privacy Rights Clearinghouse, a nonprofit consumer education and advocacy group based in San Diego, Calif.