Obtaining a commercial driving license is a good way to open up job opportunities, but you may be surprised to learn how complex the rules can be. Before you apply for one, it's a good idea to familiarize yourself with what types of licenses apply to which jobs. These are broken up into Class A, B, and C, and it is wise to never assume one license covers all jobs. Let's take a look at what each one is for and how they might apply to your situation:

Class A Licenses

The Class license largely is meant for what we stereotypically think of as trucking jobs. The vehicle must have a gross weight of at least 26,001 pounds, or it must haul a trailer or towed vehicle of more than 10,000 pounds. In additional to tractor-trailer rigs, the Class A license is appropriate for anyone who wants to operate a flatbed, a tanker, or a livestock vehicle.

Your Class A license typically allows you to run Class B and C vehicles. However, you may need to get the appropriate endorsements for the vehicle in question.

Class B Licenses

Vehicles covered by Class B include many kinds of buses and box trucks. Delivery vehicles are usually in this class, as are dump trucks and some vehicles that pull smaller trailers. This class is also home to a wide variety of different endorsements to cover things like school buses versus tour buses. While some skills may transfer among the various endorsement groups, you'll need to test on each one before you drive those kinds of rides in a commercial setting.

Generally speaking, if something doesn't quite fit clearly in Class A or C, it's a Class B vehicle. For example, pickup trucks that pull small trailers, especially ones that haul equipment or heavy loads, are typically considered Class B vehicles. Check your state's requirements for weight when using such a combination, as fines for hauling commercial-grade weights without a commercial driving license can be steep.

The Class B license sometimes allows drivers to operate Class C vehicles; as always, appropriate endorsements may be necessary.

Class C Licenses

Class C covers vehicles with at least 16 passengers including the operator that are not otherwise classified as a bus. Anything that hauls HAZMAT loads will also need be considered a Class C ride. In some cases, small truck-and-trailer combinations may be considered Class C, too.