was beset by problems, and the city shut down the entire system. A city-commissioned audit of Xerox's cameras, which was leaked to The Sun this year, showed that the errors had been more widespread than the city disclosed.

Xerox also is the speed camera vendor for the State Highway Administration and for Baltimore County.

Howard County Councilman Greg Fox, a Republican, called the inaccurate data in Howard "alarming."

"We need to make sure that we protect the safety of our children," he said. "At the same time, we need to make sure we're doing things right."

Democrat Calvin Ball, chairman of the Howard County Council, said the mistakes reinforce the importance of requiring county police to issue reports on the system. "At least there weren't any inaccuracies that affected the citizens," hesaid.

Howard County government spokesman David Nitkin said officials are looking for about 130 files out of about 6,000 uploaded throughout the year. Police Capt. John McKissick said county officials aren't certain how much information was missing from the company's report to the county. "I'm not sure we know what we don't know," he said.

Howard County's system differs in notable ways from Baltimore's. It's much smaller — four cameras compared with the 83 that once operated in the city — and it uses laser technology instead of radar to track speed. Howard County generally cites cars on single-lane roads, employs staff to constantly monitor the system and conducts hourly tests of its cameras.

But Howard County does not provide motorists with specific time stamps as some critics have called for