In order for 20 mph speed limits in residential areas to be enforced, the City must have approval from TxDOT. If not, the speed limits are statutory and set at 30 mph. I found this out from an officer when I complained of the speeders (school moms) up and down Meadow Lark, which is posted at 20 mph, the same as a school zone, but it is not enforced. If you are ticketed in a residential area in Deer Park, check the Offical, Legal speed limit that applies to that street, regardless of the signage.