The most common error I see is "kph" which doesn't even have any possible meaning. 'kilos per hour' would in most places be taken as "kilograms per hour". As in "my weight increases by 3 kph when I visit McDonalds"
Not defending 'kph' exactly, but I can see how some native metric speakers (in Australia at least) might arrive at that solution on their own.
You're right about 'kilos per hour': 'kilos' will always be taken to mean kg.
But in speech, 'kays' is a common abbreviation for both km and km/h (confusingly).
So 'kph' would be an ambiguous way of writing 'kays per hour'.
I have heard a small number of people say K.P.H. as an initialism.
kays (distance) e.g. "Thongs'll do, we're only walking a few kays down the road."
kays (speed) e.g. "Apparently he was doing 120 kays in the Barina. I'll miss him."
kph seems to come from people that normally work in miles but switched to metric for one reason or another. The common notation I almost always see for kilometres per hour would be km/h, in rare occasions with `h` exchange for whatever letter the local translation of "hour" starts with.
I don't think anyone would confuse kph for kilograms per hour (after all, that would be kgph or kg/h, and I don't think I've ever had to calculate kilograms over time outside high school anyway). Usually, context clues make it pretty clear what's being described.
There's no confusion, the problem is simply that seeing "kph" automatically expands to "kilos per hour" in non- native English brains. That's overridden by logic, obviously, but that jarring effect is always there.
kph doesn't bother me, but I'm American, and we're pretty sad and pathetic when it comes to metric, and it's similar enough to how "mph" is used here that it immediately makes sense.
What makes your specific comment funny is that we're talking about different usage of things in different languages and countries, and in one sentence you managed to express frustration at how other people say things incorrectly, while using an English idiom incorrectly. It's "drives me up the wall" (singular "wall").