> If nothing has zero emissions, then the phrase "zero emissions" would have no use whatsoever

Yes, that's the ideal: don't claim that you've achieved the impossible. I don't want to see folks marketing "perpetual motion" machines for the same reason.

For a detailed comparison:

https://www.researchgate.net/publication/297889793_Non-exhau...

Seems fair to call these vehicles "zero exhaust." Electric rail vehicles have extremely low emissions -- if the rails and wheels are carbon steel without added heavy metals, then the direct emissions are relatively benign. Maglev vehicles are even better -- but even so, there's friction with air, moving parts such as doors and lynch pins. Still not zero.

Perhaps you should explain further the distinction you are making between emissions and exhaust, and why it is correct, and why everyone else should adhere to it.

But I stand by my previous comment - you can't treat a phrase or term as meaningless just because you refuse to acknowledge the context.

The EPA[1] defines particulates produced by tires and brakes as emissions, and lists exhaust as one kind of emission. Exhaust[2] is a term used to describe the gas byproduct of a combustion engine. The "context" is a category error mistaking a part for the whole.

[1] https://www.epa.gov/sites/production/files/2015-09/documents...

[2] https://en.m.wikipedia.org/wiki/Exhaust_gas

I'm not an expert in environmental regulations, but designations like ULEV and ZEV seem to come from California and not the Feds.

So in my opinion, this is where the context is being misapplied - you want the CARB terminology to match the EPA. Neither one was handed down on stone tablets though.

The "zero emission" label is on the back on the car, maybe they should use something else for their marketing.

If you don't like "zero emissions vehicles", what do you think of:

- partial zero emissions vehicles

- transitional zero emissions vehicles (plug-in hybrids)

- advanced technology partial zero emissions vehicles

All of these have tailpipes!

To the extent that "zero emissions" does mean "no tailpipe" it's pretty straightforward and reasonable.