No. Don't use it. In hospitals, a patient who is able to walk is said to be "ambulatory," but it is used only in a medical context. You can use the word "amble," for a relaxed, slow walk, either as a verb or a noun: "Let's amble on over to the park and listen to the carillon concert." "This isn't a strenuous hike, it's just a short amble on a level trail, with a wonderful view at the end." If I heard the word, I'd be able to guess what it meant, but I wouldn't be 100% sure it was actually a word without looking it up. There's a kind of feeble humor that consists of intentionally using obscure words: "My dear, allow me to solicit your acquiescence in ambulating with me on a dilatory peregrination o'er the local prominences to enjoy the ozone and listen to the vernal bombinations of _apis mellifera_..." I DON'T recommend it.

Hello, Olga - I think you have answered this yourself! - you'll be the only person using this word, it is very old-fashioned. People would probably understand from the context, but it is never used nowadays.

As Peachey wrote, ambulate is related to amble. These are academic words with Latin roots. A person who spoke this way all the time would be considered laughable.

As you say, no it isn't common. I guess your question could be rephrased as 'who would understand me'... I would, and I guess most well-educated people would. So restrict your use to people who have been to university, and you will hopefully not get too many blank stares...

A well-placed obscure word will make you sound intelligent, but if you just throw that word randomly into a sentence then you'll just sound as if you can't speak the language properly. What about "amble"? That would fit far more contexts than "ambulate". If you want, you can try with a sentence here. Of course we can tell you if it sounds appropriate or not. :)