Some tank vehicles carry equipment that matters only when something goes wrong. Which items does CDL manual guidance tell a driver to locate and confirm are working before a trip?

Explanation

Guidance is to check whichever of these the vehicle actually carries, emergency shut-off systems, a built in fire extinguisher, bonding and grounding cables, and vapor recovery equipment, and separately to establish what emergency equipment this vehicle is required to have aboard and confirm it is there and working. The check is conditional because tank vehicles differ widely, so the driver has to learn which of these the vehicle in front of them is fitted with rather than working from a fixed list. 49 CFR 383.119(g) makes proper use of emergency systems a required knowledge area for the tank vehicle endorsement, but it names no device and prescribes no check, so the inventory above is the manual's. The wrong options shrink the list to one item or shift the job onto the terminal or the annual inspection, and the one that limits bonding and grounding to hazardous cargo misses that the endorsement turns on tank capacity rather than on the cargo being hazardous.

Source: 49 CFR 383.119(g)