Speed Camera Vendor: Timestamps Not Accepted Method to Calculate Speed
Howard County's speed camera vendor said timestamps on photos are not an accurate method for calculating speed.
Over the past few months, the Baltimore Sun has been cataloguing what may be errors in speed cameras in Baltimore city. Reporters have used time over distance calculations with timestamps on citiation photographs rounded to the thousandth of a second to determine drivers' speed.
In Howard County, it's not possible to use timestamp information to determine speed because the timestamps are rounded to the nearest second, which is not precise enough to make a calcualtion, according to the Sun.
However, even if it was down to the thousandth of a second, citizens would still not be able to calculate their own speed at the time of the infraction, according to a spokesperson for Xerox State & Local Solutions Inc., Howard County's speed camera vendor.
"Time over distance calculations have never been accepted as a primary means of determining speed in photo enforcement," wrote Chris Gilligan, a Xerox spokesperson, in an email. "In Howard County, the timestamp generated on each violation photograph represents the time at which the system validated the vehicle's speed, not the time at which each image was recorded."
Gilligan said due to the angles at which cameras are placed in the county—in mobile vans along the side of the road—that "it is nearly impossible" to determine the exact location of the vehicle, which is required to make an accurate time over distance calculation.
In addition, speed cameras in Howard County use laser technology rather than radar technology. Baltimore City cameras use radar, according to Gilligan.
Laser cameras shoot a focused beam of light at a vehicle, which is reflected back. The time the light takes to reflect back is then used to calculate the vehicle's speed, according to an article on AOL Autos. Radar cameras are similar, only instead of using lasers they use radio waves to determine speed, according to the article.
Both radar and laser speed measurement technologies have been proven accurate for decades, according to a USA Today report, although lasers are believed to be slightly more accurate.
Currently, Howard County operates only two speed cameras, which are kept in vans that move to different positions throughout the county.
Legislation passed in 2011 by the Howard County Council allows police to station up to 8 mobile vans in school and work zones, but so far, county officials have only moved forward with two.
The cameras, which are in operation from 6 a.m. to 8 p.m., issued approximately 100 citations per day during their first two months in operation, according to police.
In December, police said they would work with Xerox to provide more information on speeding citations issued to residents if the information would increase motorist confidence in the program.