Which vital sign is NOT mentioned as a mandatory part of the examination?

In the context of the FMCSA DOT physical examination, the respiratory rate is not listed as a mandatory vital sign that must be recorded during the examination. The focus of the evaluation is primarily on those vital signs that have a direct impact on assessing an individual's suitability for driving commercial vehicles, such as pulse, blood pressure, and height.

Pulse and blood pressure are critical for identifying cardiovascular health and recognizing conditions that may lead to medical issues while driving. Height is also recorded, as it helps determine the body mass index (BMI), which can be an important factor in evaluating a driver's overall health and fitness for the job.

While respiratory rate can provide useful information regarding an individual’s respiratory health, it is not required as part of the standard assessment protocol, thus making it the correct answer to the question about which vital sign is not mandatory during the DOT physical examination.