Meta explanation: a PITTSBURGHLEFT is a left turn at an intersection with no protected turn lane made as soon as the light turns green, without yielding to oncoming traffic. (Do not try this anywhere except Pittsburgh and its environs. And if you are unfamiliar with this maneuver and you happen to be driving in Pittsburgh, just FYI people absolutely do this.) Four symmetric car makes in the grid - KIA, FORD, JEEP, and GMC - are the "oncoming traffic" here, as hinted by their clues, and four other car makes are making left turns in front of them. Toyota, formed from OTIOSE and GATO, is turning in front of KIA, but the black square at the end of KIA is covering the Y. Cadillac (DACE, CALL) is turning in front of FORD with the I covered by the black square. Honda (TOHO, DAHS) is turning in front of JEEP with its N missing. Mazda (DHARMA, DANI) is turning in front of FORD and missing its Z. The missing letters spell the meta answer, YINZ, which is the Pittsburgh equivalent of "y'all." Thanks for solving!