the indication that they have started the clock on your car and that they are coming back to give out tickets

so if you back up for a foot, and bury this chalk mark... you win  Two months ago I posted this when they used a chalk to mark a tire, this time they bag bombed the tires http://justacarguy.blogspot.com/2013/10/if-you-ever-park-in-one-of-timed-zones.html