Flashcard 12 - Combination Vehicles Flashcard Set for the CDL


The correct answer is:

The service line is blue and the emergency line is red. The glad hand connections are often colored, as well, to indicate emergency vs. service line.


Rarely, a line or connector will not be color coded. Instead, there will be a tag or label reading “Service” or “Emergency.”

All Flashcard Sets for the CDL are now available as downloadable PDFs