CDL Exam contains more than 600 questions to help you pass the California Commercial Driver License exam. Questions are classified into 8 categories: - Commercial Driver License Knowledge Test - Passenger Transport Endorsement Test - Vehicle Code and Safety Driving Practices - Hazardous Materials - Air Brakes - Combination Vehicles - Doubles and Triples Vehicles - Tank Vehicles At the end of each test, a summary is given highlighting the questions that need more review. One can also bookmark the key questions for later study.