According to the Department of Motor Vehicles, there are approximately 50 to 80 questions on the Commercial Driver's License exam. The questions are grouped into different categories, with each category having a different number of questions.
The CDL exam has a knowledge category that is considered a general section. Every individual trying to get a CDL is required to take the knowledge test. Depending on the state, the exam is broken into different categories, the most common being the following: H (hazardous materials), T (double/triple trailer), N (tank), P (passenger) and S (school bus). Which section a driver has to take is determined by which class the driver is trying to obtain.