Final answer:
The second violation of a railroad-highway grade crossing regulation within three years may result in a CDL being disqualified for at least 60 days to ensure safety at rail crossings.
Step-by-step explanation:
The question pertains to the rules concerning the operation of a Commercial Driver’s License (CDL), particularly about railroad-highway grade crossing violations. If the question is seeking information on the penalties associated with such violations, the answer would be that the second violation of a railroad-highway grade crossing regulation within a three-year period can lead to the disqualification of a CDL for a minimum of 60 days. This is because maintaining safety at railroad crossings is critical, and federal regulations are strict in order to prevent accidents that could be catastrophic due to the size of commercial vehicles and the potential for serious collisions with trains.