Most times, local jurisdictions set speed limits near public schools at 20 MPH. Washington State Law sets the limit at 20 MPH. Some areas in Texas and Mississippi set a limit of 15 MPH. During severe weather, some jurisdictions set a limit of 10 MPH in snow, or glare ice conditions. I have seen school districts set mandatory stop zones, where a crossing guard gives the motorist clearance to pass.
Know that if you go speeding through a school zone, the fine can be increased according to the attitude of a judge. DWI and speeding in a school zone is usually a good excuse to say goodbye to every nickel you have and your home for a year per MPH over set limit AND every .01% you blew above .08 BAL.
ONE DWI is a good way to lose your CDL. Speed and DWI is enough to make the judge tear a trucker a new backside big enough to drive his rig through -- and by the time the judge gets through with you, you may wish that he had.