In any situation when passing a large truck (or even a large bus). These kinds of vehicles tend to have very large blind spots, and they have multiple large blind spots. The Department of Transportation suggests that you make sure you can see the driver of the truck in the truck’s mirror before you start trying to pass. Passing from the right is always going to be harder because the right blind spot is larger, so it’s suggested you don’t pass on the right.
Finally, when passing a large truck or bus, it’s important to be aware of your surroundings. It takes these vehicles longer to stop, so if you’re in an area you know well, avoid the spots where it will be stop and go traffic or where you know that a light is short. Passing here is a bad idea.