Which factor is not considered crucial for a CMV driver with a history of substance abuse?

The age of the driver is not considered a crucial factor when evaluating a CMV driver with a history of substance abuse. The focus for assessing fitness for duty lies primarily on behaviors and circumstances related to the substance abuse history, such as whether the individual is receiving ongoing counseling, the time elapsed since their last use of substances, and their participation in support meetings.

These aspects provide a clearer insight into the individual's current state of recovery and readiness to operate a commercial motor vehicle safely. Age does not have a direct correlation with substance abuse recovery or driving capabilities. Therefore, while age may influence other health factors, it does not play a significant role in determining the suitability of someone with a substance abuse history for operating a CMV.