Elon Musk's Tesla is now America's most valued automaker, but you'd never know it from his employee parking lots ... which look like a total over-packed disaster zone.

The Wall Street Journal posted a report on 2 of the company's parking lots -- one at the Palo Alto HQ, and another in Fremont, CA -- and they've got cars double parked, stacked like sardines ... or even parked on top of curbs and medians, often back to back.

The issue's pretty obvious ... not enough spaces to accommodate Tesla's growing staff. Like, not even close. Elon's reportedly working on a long-term solution.