If it's running equipment (refrigerator, loading deck, food truck, overnight accommodation, cold weather, etc).

If they really want to make a difference, they should enforce this against individuals too, not just companies. Lots of people leave cars idling when waiting in the heat/cold/rain. That adds up too.

Refrigerated trailers have their own separate engine.

Refrigerated box trucks don't have a separate engine for the box.

Yep, and those are generally more common in the cities.

I don't think the distinction between soot and poison really changes the willingness of someone to physically attack a snitch.

As for legitimate reasons to leave it idle, I have no idea.

> As for legitimate reasons to leave it idle, I have no idea.

Air conditioning/heating

If you get in and out of the cab all day, wear more clothes. That's what I did, worked great. In the summer it's just not that big a deal, you're sweating in every other part of the job anyway. Roll the windows down maybe.

If you're talking about the cargo, the insulation will easily keep up over an hour or two plus of being stopped.

Driving with frosted up windows is not safe

I'm not sure what this comment means, sorry.

You run the heater to defrost the glass in your car. It often takes a few minutes for it to be effective. Otherwise, you can’t see and you’re a danger to yourself and others.

In the winter, it’s more common than putting gas in your car. It’s kinda odd explaining this though

I live in the subarctic region, a stone’s throw away from the arctic circle. We have snow and frost in winter.

We use ice scrapers. :) As a matter of self-reliance and/or common courtesy.

Defrosting the windows with the engine is really not nice, especially not when it’s a diesel with the fumes hanging in the winter air and going inside people’s windows and into baby carriages and kindergarteners’ noses.

It's not only not nice, it's a genuinely bad idea. If you have large sheets of glass (truck windows) and large heat differentials, you are asking for catastrophic failure due to uneven expansion. I know multiple people this has happened to personally, and there are also some truck manufacturers who recommend against this kind of defrosting for exactly this reason.