Nelson said the new cameras might result in less revenue for the city because they will be more conservative in determining when a driver has exceeded the speed limit by 12 mph or more, the threshold in state law.
"The downside is our system will kick out more than not," Nelson said. "You have a system that will err on the side of the driver."
Baltimore City Councilman Robert W. Curran said it didn't bother him that the new cameras would likely generate less revenue.
"Obviously, we need to be accurate," he said. "It's not about the revenue. The public needs to be confident in the system."
City officials did not say when the replacement process will begin or how long it will take, and Barnes said the government will not publicize when cameras are offline "in the interest of public safety."
Even as the city pledged to buy new cameras, there appeared to be confusion about who is currently operating the city's speed cameras — or whether the cameras are operating at all.
The city's speed camera system has been in transition since Jan. 1, when Baltimore terminated its contract with Xerox, which served as the city's speed camera contractor since 2009. Hanover-based Brekford won a bidding competition to take over but has yet to sign a contract, according to Brekford.
Xerox spokesman Chris Gilligan said that on New Year's Eve, "our contract expired and the city began its transition to a new vendor." On Wednesday, Barbara Zektick, chairwoman of a city task force studying the cameras, said Brekford has "actively stepped in."
But Nelson said Monday that the company had not yet begun managing the city's cameras because it had not signed a contract.
"I have no idea," he said, when asked who is currently running the speed cameras. "As soon as the ink gets placed on the contract, I am prepared to do what we have to do."
Nelson said he believes the city's current crop of cameras suffer from several well-known radar errors, including beams measuring the biggest object on the road — but ticketing smaller ones — and bouncing off several objects, producing erroneous readings.
The new radar systems, he said, "won't make those same mistakes."
Ely said it's hard to say how much difference the new cameras might make because the city hasn't provided technical specifications of the existing cameras. Regardless of technology, he said the city will need to ensure a strong review process and employ a secondary verification method, such as painting white lines on the road to show how far a car travels in the split-second between the two photographs the cameras are required to produce under state law.
"Doing that type of verification is what will prevent errors in the future," Ely said. City officials "have to assume the devices are capable of being wrong. If they do otherwise, they'll wind up in the same situation later."