What is the FEV1 threshold for disqualification due to lung function?

The FEV1 (Forced Expiratory Volume in 1 second) threshold for disqualification due to lung function is set at 65% predicted. This standard is rooted in the need to ensure that individuals can perform the essential duties of driving safely without the risk of significant respiratory impairment. A FEV1 less than this threshold indicates a level of lung function that may be inadequate for activities requiring exertion, such as those associated with operating a commercial vehicle.

When evaluating lung function, the measurement of FEV1 is critical, as it provides insight into the airway dynamics and overall respiratory health of an individual. At a level of 65% predicted, there is a significant concern regarding the potential for respiratory distress which could impair the capacity to manage the vehicle effectively, particularly in stressful or emergency situations.

The higher percentage thresholds, such as 75% or 85% predicted, represent levels of lung function that are generally considered acceptable for driving, while the lower threshold of 55% would raise serious concerns about the person's ability to facilitate safe driving practices. Thus, the 65% predicted is a medically established point where driving capabilities may be compromised, leading to potential disqualification from driving duties.