The lack of tickets has also caused some problems for Brekford, which has been losing money and informing investors that it is awaiting revenue from the Baltimore program. In a statement to investors, Brekford said the company lost $1.2 million in 2012, in part because it had to buy and install new cameras for Baltimore to replace the old ones. Recently, the company reported a net income of $76,000 for the first three months of 2013, but a loss of $476,000 from April through June.

"We incurred significant costs in anticipation of our role as the primary vendor in the implementation of Baltimore's Automated Traffic Enforcement Program," C.B. Brechin, CEO of Brekford, said in a statement to investors in August.

Until this year, the cameras were a big revenue source for the city, yielding about $50 million just from the speed cameras since 2009.

After The Sun published its findings last fall, Xerox State and Local Solutions, the city's contractor until Dec. 31, acknowledged that five of 83 speed cameras had error rates of 5 percent, prompting the city to take those offline. Rawlings-Blake publicly committed to replace all city speed cameras with newer models that use more sophisticated tracking radar.

The city's camera system was shut down after Jan. 1 amid a bumpy transition from Xerox to Brekford. Brekford said Xerox did not leave behind software needed to operate the cameras, while Xerox contended that its software is proprietary.

The city began issuing speed camera tickets in February using new cameras from Brekford. It also was able to start using the existing red light cameras. But in mid-April, the city suspended the program because of new errors, officials said.

According to city records, Baltimore has cut a check to Brekford for speed and red light camera services once so far: $700,000 in August. Kevin Harris, a spokesman for the mayor, said the invoice was a partial payment for Brekford's purchase of 72 speed camera units, for which the city agreed to pay $2.2 million.

Scott said he was concerned the city was making payments to Brekford for cameras that are not ready for use.

"It does concern me any time we're paying taxpayer dollars and not getting a benefit," he said. "I hope they sort this out and get this issue resolved."

Brekford has also run into issues in other jurisdictions. This year, police departments in Greenbelt and Hagerstown have voided or issued refunds for hundreds of speed camera tickets because some radar units weren't calibrated annually, as required by state law.

Baltimore County experienced the same issue with its vendor, Xerox, earlier this year, prompting officials to void more than 1,400 citations and take 12 cameras out of service for more than a month. County officials never alerted the public about the lapse until last week, when asked about the issue by The Sun.

Baltimore Sun reporter Scott Calvert contributed to this article.