Runaway Float / Partners - S2-E20
Continuity mistake: When Arnold stands up on the bike before jumping onto the parade float, Eugene's hair disappears mid-shot. (00:10:11)
Mud Bowl / Gerald Moves Out - S2-E9
Continuity mistake: When Gerald catches his little sister destroying his cassette tape, the book she is wrapping changes color from blue to green. (00:12:30)
Continuity mistake: In "Miss Perfect", Helga, Rhonda, Sheena, Phoebe, and Nadine are cooking up ways to make Lila's (the new girl) life miserable. In one shot, Rhonda is wearing her new blue outfit. When the scene cuts to the boys and Lila, and then back to the five girls, Rhonda is wearing her standard red sweater and black pants. For the rest of that day, she is back in her new outfit.
Coach Wittenberg / Four-Eyed Jack - S2-E16
Factual error: When the kids are bowling for the first time, the placement of the pins is wrong, and when Arnold is bowling there are 11 pins.
Eating Contest / Rhonda's Glasses - S2-E13
Continuity mistake: In the last scene, Rhonda is seen through the bus's rear window as sitting in the back of the bus - but just before that, she's talking to the girl with the frizzy hair in a seat closer to the front.
Freeze Frame / Phoebe Cheats - S2-E8
Continuity mistake: The next night, Phoebe's bed clothes switch back and forth between her nightgown and her dress.
Answer: The show is based in present day times. Plus most cars aren't old fashtioned, I recall seeing a limo and not to mention a cherry picker, etc.