16-year-old KENDALL JENNER was spotted TEXTING WHILE DRIVING in her new, $90,000 Range Rover.  (--Check out a picture here.)

--Now, it should go without saying that texting while driving is STUPID.  For ANYONE.  Let alone a 16-year-old.  But it's also ILLEGAL in the state of California.

--And drivers under the age of 18 aren't even allowed to use a HANDS-FREE phone while driving.  Oh . . . and this is the SECOND time in two months she's been seen texting behind the wheel.

--The guy who caught Kendall this time says she was, quote, "swerving in her lane, from one side to the next, and she wasn't paying attention to other drivers."