What are the requirements to obtain a commercial driver's license (CDL)?

To obtain a commercial driver's license (CDL) in the United States, there are several requirements to fulfill. Firstly, you must be at least 18 years old to obtain a CDL for intrastate transportation, although for interstate transportation, you must be at least 21 years old. Secondly, you must hold a valid driver's license and provide proof of legal presence in the country. Additionally, you must pass a written knowledge test, covering general knowledge and specific endorsements relevant to the type of commercial vehicle you intend to operate. After passing the knowledge test, you need to obtain a learner's permit and practice driving under the supervision of a CDL holder. Lastly, a skills test, including a pre-trip inspection, basic vehicle control, and an on-road driving test, must be passed to receive a CDL.