No employer may allow, require, permit, or authorize a driver to operate a CMV in the United States if he or she knows or should reasonably know that any of the following circumstances exist:

(a) During any period in which the driver does not have a current CLP or CDL or does not have a CLP or CDL with the proper class or endorsements. An employer may not use a driver to operate a CMV who violates any restriction on the driver's CLP or CDL.

(b) During any period in which the driver has a CLP or CDL disqualified by a State, has lost the right to operate a CMV in a State, or has been disqualified from operating a CMV.

(c) During any period in which the driver has more than one CLP or CDL.

(d) During any period in which the driver, or the CMV he/she is driving, or the motor carrier operation, is subject to an out-of-service order.

(e) In violation of a Federal, State, or local law or regulation pertaining to railroad-highway grade crossings.

[76 FR 26879, May 9, 2011, as amended at 78 FR 60231, Oct. 1, 2013]