New speed cameras won't eliminate errors, radar experts say

'Tracking' radar still requires oversight, calibration

February 17, 2013|By Scott Calvert and Luke Broadwater, The Baltimore Sun

Baltimore transportation officials have set high expectations for the city's new speed cameras, telling state lawmakers the devices won't be susceptible to errors that plagued the system over the past three years.

"We won't have this problem moving forward," said Barbara Zektick, acting deputy transportation director, at a recent briefing for the city's legislative delegation.

"The new cameras have tracking radar," said Frank Murphy, the agency's acting director.

But radar experts say tracking radar isn't necessarily the cure-all it might seem. They predict the new cameras will reduce — but not necessarily eliminate — the kinds of errors that have cast a shadow over the city's automated enforcement system. Those errors, many of which came to light in a Baltimore Sun investigation, have included generating excessively high speed readings and tagging the wrong vehicle as the speeder.

Speed cameras will be on the agenda in Annapolis this week. A wide-ranging reform bill sponsored by Sen. James Brochin, a Towson Democrat, is scheduled to be heard Wednesday at 1 p.m. by the Senate Judicial Proceedings Committee. One provision would more explicitly bar the so-called "bounty system" that pays contractors based on the volume of citations.

While city officials believe tracking radar will produce more accurate results, experts say a rigorous human review process and frequent calibration of the cameras will remain essential if the city wants to move toward Mayor Stephanie Rawlings-Blake's goal of achieving "a zero-error program."

"In the laboratory, in the hands of a skilled scientist, these things could be tested and proved reliable," said Christopher Davis, an electrical and computer engineering professor at the University of Maryland. "But put out on the street and left there for months at a time, I wouldn't have confidence they'd give reliable readings 100 percent of the time."

City officials have emphasized that, while they trust the new cameras, they will also beef up the process of reviewing and verifying the automated cameras' citations before they are mailed to motorists for payment of the $40 fine. A key change will be at the Police Department, where officers had been checking up to six tickets per minute. The department says it will double the number of officers available to review citations and have supervisors spot-check their work.

After initially planning to continue using its existing 83 cameras, the city decided to replace them as it switched to a new vendor, Brekford Corp. of Anne Arundel County, Jan. 1. The new cameras cost the city $25,000 apiece or about $2.1 million in all. Some are in operation, and all are scheduled to be in place by late March.

In documents filed with the city last year, the company said Baltimore "will be the first municipality to be offered this technology by Brekford."

As its name suggests, tracking radar tracks objects — in this case, cars and trucks — as they pass a camera. Brekford says it will help ensure accurate readings and avoid citing the wrong vehicle.

The new system is an improvement because the previous models took more of a radar snapshot and were more prone to various errors, said Fernando Berra III, a photonic engineer in private industry with 20 years of experience in laser and radar systems. With multiple radar readings, it will be apparent if there's an error because the speeds won't be consistent, he and other experts say.

"If done properly, it would absolutely minimize the issues," Berra said of the tracking radar. Still, he said, while the technology is reliable, trained technicians will be needed to examine the results.

One challenge that will remain even with tracking radar is correctly determining who is speeding when multiple vehicles are on the road, as often happens in the city, said Jin Kang, chairman of the Electrical and Computer Engineering Department at the Johns Hopkins University.

"The problem is that they will still have a difficult time analyzing which [radar] signal corresponds to which vehicle," Kang said. "It requires somebody sitting there analyzing the results."

The Police Department's practice of having a single officer review several tickets per minute "makes no sense," Kang said, adding: "That person has to spend at least a minute or five minutes per photograph to make an error-free analysis."

Davis, the Maryland professor, said the only surefire way to check the tracking radar's accuracy will be for a reviewer to have a way of comparing the speed reading with physical evidence of how far the vehicle traveled. Because speed equals distance over time, he explained, it's possible to double-check the radar using time-stamped photos and pavement markings.

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