A law that would have brought about 40 speed-detection cameras to New York City stalled in the state Senate earlier this month, and won’t be reconsidered until 2013.

Meanwhile, across the Hudson River, another law aimed at the traffic-policing technology is being considered by New Jersey’s state leaders. This one, however, is aimed at taking cameras off the streets.

The pending laws are examples of the debate going on in state and local government houses across the country: some embrace camera-based technology as a cost-efficient law-enforcement and safety tool; others cast it off as an overly intrusive money grab.

“The cameras are not about safety; they’re about generating revenue for municipalities,” said New Jersey state Sen. Mike Doherty, the sponsor of a bill that would ban the use of red-light traffic cameras throughout the state. “The towns are using their citizens as cash cows.”

New Jersey isn’t the only state where the cameras have drawn fire. Both Houston and L.A. shut off red-light cameras in 2011, while attempts to ban red-light and speeding cameras failed in Colorado and stalled in Iowa earlier this year.

In all, 12 states have banned speed-reading cameras, according to the Governors Highway Safety Association, while 13 states utilize them. Twenty-four states (and the District of Columbia) are currently operating at least one red-light camera within their borders, while another nine have passed laws prohibiting their use. (Despite the conflicting laws, overall use of cameras has gone up rapidly in recent years: red-light cameras were in 25 communities in 2000, compared with more than 500 today. Speed cameras went from 20 jurisdictions in 2005 to 113 today.)

Where they are in use, digital cameras are typically mounted above a traffic signal or along a stretch of road. Depending on the camera’s purpose, it’s triggered to snap photos when a car passes a certain point or exceeds a designated speed limit. Using license-plate information, a traffic ticket is then issued to the owner of the offending vehicle.

Court enforcement of camera-generated tickets varies widely by state, but the general idea of using the cameras has received overwhelming judicial approval, and advocates say the technology helps keep roads and streets safer.

“The research studies of red-light and speed cameras show that they are effective in reducing the behaviors—running red lights and speeding—and reducing crashes,” said Anne McCartt, senior vice president for research at the Insurance Institute for Highway Safety (IIHS).

While some opponents cite the “kangaroo effect” that speed cameras may cause—a driver slams his brakes when he notices a speed camera, causing the following car to plow into him—an oft-cited 2011 study by the Cochrane Collaboration in Australia found that car crashes declined by anywhere from 8 percent to 49 percent in the 35 speed-camera sites studied.

The data on red-light cameras, however, is murkier.

A study released by the IIHS in February 2011 found that the combined per capita rate of fatal red-light running accidents fell by 35 percent (PDF) in 14 large cities utilizing red-light cameras, including Chicago, D.C., and San Diego, when compared with an earlier period before the use of cameras.

Studies from both the Federal Highway Administration and Virginia Transportation Research Council, on the other hand, indicate that while red-light cameras are effective in reducing certain types of accidents—including “t-bone” or broadside collisions, which can be severe—they likely also cause more rear-end crashes.

But for some of the more vocal critics of automated traffic enforcement, it’s not a matter of whether the technology works, but the cameras’ purpose in the first place.

“We think they started off with legitimate concerns and legitimate goals related to traffic safety,” said John B. Townsend II, the public and government affairs manager for AAA Mid-Atlantic, referring to the red-light and speed camera program currently in place in Washington, D.C. “Then they discovered there was a pot of gold at the end of that rainbow.”

Gold indeed: The District raked in $55 million in revenue from the cameras last year, the most so far under the program, despite issuing fewer tickets than in 2010. That’s because the city increased the fines for a number of traffic infractions, including a right turn on red, which doubled from $50 to $100, and red-light running ($150, up from $75). Mayor Vincent Gray’s 2013 budget proposal anticipates an additional $30 million in revenue based on plans to expand the use of cameras throughout the city.

A spokeswoman for the D.C. police department said, “We constantly receive requests from residents for increased enforcement in their neighborhoods and we move our resources to new sites to accommodate those requests and reduce speeding, fatalities, and crashes. The goal is safer roads for everyone using them.”

So, the cameras enforce the laws on the books and bring in revenue. (A red-light camera program in Chicago reportedly brought in $69 million in 2010.) As cash-strapped cities and states continue to struggle to recover from the recent recession, isn’t this a good thing?

“The cameras are not about safety, they’re about generating revenue for municipalities,” said a New Jersey state senator. “The towns are using their citizens as cash cows.”

“You can’t argue the fact that they’ve had a significant reduction in traffic accidents in D.C.,” Townsend said, “but don’t exploit people just for the sake of revenue.”

According to some experts, the line between enforcement and exploitation is blurred by the fact that red-light and speed cameras are typically operated by private, profit-motivated contractors. Last year, the United States Public Interest Research Group issued a report spotlighting what it called “the most problematic” contracts between the companies that make and operate traffic enforcement cameras and the localities they serve. These agreements, according to the report, dictate that the contractor is paid per ticket issued, providing a financial incentive to churn out as many tickets as possible.

Combined with concerns that speed limits are artificially low in some camera-enforced stretches of road, and that yellow lights are unnecessarily short—New Jersey recently suspended its red-light camera program, finding that the state had not properly reviewed the length of yellow lights at monitored intersections—the system is a conspiracy theorist’s playground.

Yet for American Traffic Solutions, which provides cameras to New York and D.C. along with a number of other localities, these “per-ticket” contracts represent only a small portion of the company’s agreements with government clients, according to vice president of communications Charles Territo. Most clients choose instead to operate under a “max price” arrangement, in which the amount due to the company depends on the revenue generated by a particular camera each month, up to a certain amount. While there is still an incentive to issue enough tickets to reach that amount, Territo’s response is that if drivers don’t want to be fined, they should obey traffic laws.

“Red-light and speed-safety cameras only generate revenue when drivers exceed the speed limit or run red lights,” Territo said.

But there are other incentives for contractors to keep the cameras churning, according to the PIRG report’s author, Phineas Baxandall, who said the more money a camera generates in ticket revenue for a client, the more likely the client is to tap the contractor for more cameras. If the cameras’ purpose is to improve traffic safety, Baxandall suggested that perhaps the compensation system for camera operators should be recalibrated.

“I’m not aware of any situation in which compensation is based on the number of accidents or fatalities prevented,” Baxandall said.

In other words, camera-generated tickets may be penalizing drivers for running reds, but they’re also generating a lot of green.