The median household income is around $50k/yr in the U.S. That's household income. To the extent people are spending this much, they're insane for doing so.

I'm having trouble finding a median car sale price -- there are a bunch of articles about the average cost of new cars -- but I doubt most families actually are spending that much on transportation. Once you cut out used cars, those without cars, and those spending significantly less for their Kia or Hyundai or whatever, I think you'll find that very few people spend $40k on a car. That's a luxury purchase.