Slow down, D.C. Or at least smile as you speed.

Last week, the Metropolitan Police Department announced the installation of nine new speed cameras throughout the city. The cameras join a growing network of mobile and fixed traffic enforcement cameras across the District that, depending on who you ask, make us all safer drivers or simply extract more and more cash from anyone who gets behind the wheel of a car. (One of the new mobile speed traps is pictured above.)

According to MPD, tickets issued for speeding increased from 275,000 in 2007 to 354,000 in 2010, resulting in a jump in revenue from $20 million to $24 million over the same period. Let’s not pretend that revenue doesn’t matter for traffic enforcement cameras — in June, city officials were upset that not enough people were running red lights.

If you think these cameras are a pain, at least you know they’re there, right? The same can’t be said for the many police car-mounted license plate scanners, which the Post recently reported are being used to feed information about your car into a vast database that can then be used to fight crime. According to the article, the District has one plate-reader per square-mile, the highest concentration in the whole country.

MPD isn’t totally heartless when it comes to these new cameras. As of November 21, anyone caught speeding by them within a 30-day period will merely be mailed a warning. After that, you’re stuck with the full fine.

View New Speed Cameras in a larger map