Because it's REQUIRED to maintain your Commercial License!
Federal Motor Carriers Safety Administration (FMCSA) wants to minimize the risk of a commercial driver having some sort of incapacitating incident that would put the driver and / or public in danger. It's important that commercial drivers operating on our roads are fit and capable of handling the rigors related to both short and long distance trucking.
When you successfully pass all the aspects of a driver physical issued a Medical Certificate, it is usually valid for a set period of 2 years (Maximum). However, if you have any medical condition such as hypertension, diabetes or sleep apnea just to name a few then the certificate would likely be limited to 1 year. When any physical limitations are found, such as arthritis, severe back pain, hearing or visual deficiencies, you may be sent to your primary care doctor or specialist (optometrist, audiometrist, etc.) to correct or give clearance for deficiency
The process of an examination is quite straightforward. It begins with discussing your medical history. In addition, you must list any prescription medications with dosage you are currently taking.
The physical exam consists of checking hearing, vision, blood pressure, pulse, urine (specific gravity, protein, blood & sugar) Height & weight are also checked. Drug testing is not part of the DOT/CDL physical exam.