The city of San Antonio, Texas has had a Safe Passing Ordinance on the books since 2010. The local law requires at least three feet of passing distance when a driver passes a ‘vulnerable user,’ which includes pedestrians, cyclists, highway workers and even people on horseback.
To give this ordinance some teeth, San Antonio bicycle officers are riding through downtown, with other officers in cars following and observing driver behavior. When they see somebody passing too closely, they nail the driver.
Story at WOAI News 4: Undercover bike officers target unsafe drivers.