Are the cars gone?

Prologue: Max, Emma, Dad, Uncle Ed, and Tanta Anna went on a trip to downtown Minneapolis earlier in the day to visit the Stone Arch Bridge and the Mill City Museum. On the way, he asked what road we traveled on whenever there was a turn.

Setting: Max is struggling to go to bed. He calls down to Mom from behind his closed bedroom door.
Max: "Mom, is it dark yet?"
Mom: "Yes, Max. It's dark."
Max: "Are the cars gone?"
Mom: "What cars Max?"
Max: "The cars on the road."
Mom: "What road?"
Max: "On Highway 12, Highway 15, and Highway 110?" (3 of the highways we traveled on)