Free tanker endorsement practices tests are the best way to make sure you pass that part of your commercial driver's license test. Questions could be how you use the brakes on a steep downgrade, or the most common cause of skids. They will ask about blood alcohol content, and if you can haul hazardous with a tanker endorsement. Other questions will be about driving through deep, standing water,
. and how much liquid to load in the tanker. A practice test for tanker endorsement can be found at http://www.infotrucker.com/cdl/cdl1-30-test.html.