Revenue from traffic enforcement cameras, such as this one in the 100 block of H Street NE in Washington, has sharply declined. (Joel Richardson/The Washington Post)

D.C. police acknowledged this week that a sharp decline in revenue from the city’s network of traffic enforcement cameras was due in part to problems maintaining some of the equipment — undermining earlier claims that the drop was mainly due to motorists doing a better job obeying the law.

Assistant Chief Lamar D. Greene, who oversees the camera program, said in a statement that severe weather last year contributed to the maintenance issues.

“During periods of extreme cold and snow last winter, there were instances when we could not change the batteries because they were not accessible, or the temperature affected the charge,” he said. “We have taken additional steps to enhance internal temperature controls since last winter, alleviating this problem.”

The police department responded after D.C. Council Chairman Phil Mendelson (D) blamed the maintenance problems for a $38 million reduction in camera revenue at a budget briefing Monday morning. Mendelson said the issues arose after the police department assumed direct responsibility for the operations of the cameras.

Previously, the cameras’ maintenance had been the responsibility of the contractor, American Traffic Solutions, that provided the equipment and processed the tickets.

In fiscal 2012, the camera program raked in more than $85 million, according to figures provided by the D.C. Office of the Chief Financial Officer. That dropped a bit in fiscal 2013, to about $75 million, amid a debate over the expansion of the program and small adjustments to fine amounts and speed limits.

In fiscal 2014, which ended Sept. 30, the city took in less than $34 million.

When city financial officials warned about the precipitous drop-off in camera revenue in September, maintenance concerns never figured into city officials’ public explanations for the shortfall.

Police Chief Cathy L. Lanier said at the time that the revenue figures represented proof that the cameras were working to reduce speeding and red-light-running.

“This demonstrates that drivers are changing their behavior,” she said in a statement. “The fact that infractions are going down is a good thing in my view. Automated traffic enforcement is and always has been about safety.”

A spokeswoman for then-Mayor Vincent C. Gray (D) cited delays in deploying some new enforcement devices and higher speed limits on some streets — but did not mention maintenance concerns.

“As we’ve said all along: The purpose of automated traffic enforcement is to improve public safety and save lives, not to raise money,” said the spokeswoman, Doxie McCoy.

Cold weather may not fully explain the revenue shortfall: Monthly cash reports issued by the Office of the Chief Financial Officer show revenue problems developing in the late summer of 2013, with collections fluctuating wildly month to month over the subsequent year.

Greene, in his statement, also cited increased compliance for contributing to the drop in camera revenue, and he noted a 10 percent drop in traffic fatalities recorded in 2014.

“It should be noted that speed limits on some streets have been raised and more motorists are obeying the law and have begun to slow down,” he said. “Automated traffic enforcement is and always has been about safety, and we are encouraged that drivers are modifying their behavior.”

The $38 million decline in revenue from traffic cameras added urgency Tuesday to the first meeting between new D.C. Mayor Muriel E. Bowser (D) and members of the D.C. Council.

Bowser said the revenue shortfall has exacerbated the financial problem the city faces now that it has also “lost” a legal battle over $47 million in back overtime owed to firefighters.

“If we were counting on those dollars,” Bowser said, “we have to make it up somewhere.”

The new mayor said she was aware that maintenance was a root issue of the drop in ticket revenue but said she had not been briefed on the specifics.

“I think that they were delayed in being installed or turned on when they should have been,” Bowser said. “I don’t know the details of which, or really, why. But I do know that it has created a shortfall.”

City officials familiar with the camera program but not authorized to comment publicly on it said Gray deputies had to scramble last year to get the system back on track after learning of the revenue dip. The officials confirmed the police department had brought the maintenance functions in-house but did not know the rationale for or the timing of the move.

Police officials did not respond Tuesday to additional questions about the camera program.

Revenue appears to have rebounded significantly in recent months; city data shows collections of $13.1 million for October through December, the first three months of the 2015 fiscal year.

Mendelson blamed the city for turning photo enforcement into a revenue stream that the city depends on to balance its growing spending.

“Public safety should be about making sure motorists are not running red lights and not speeding,” Mendelson said. “When we become too greedy about how much we are going to get in revenues, then when there is the slightest blip, we have a budget problem.”

Aaron C. Davis and Peter Hermann contributed to this report.