Are you supposed to Cary with a copy of DOT medical card when drive?

In the United States, commercial vehicle drivers are required to have a valid Department of Transportation (DOT) medical card in their possession and must present it to a law enforcement officer upon request. The DOT medical card certifies that the driver is physically qualified to operate a commercial motor vehicle (CMV). The card must be kept in the driver's possession while operating a CMV, and must be presented to any law enforcement officer upon request.