"Trying to drive up the Hume Highway for several hours in 43 to 45 degree heat with no airconditioning (broken) was quite taxing, and we had to stop in a slightly cooler roadhouse so my mother wouldn't conk out (she's 90)."
What that highlights is that modern cars have been designed to only be habitable with air conditioning. I have several vintage cars, they have a more vertical windscreen so the sun does not beam in, and they have quarter windows and vents, they are much cooler.
Modern cars tend to have vast glass areas and plastic interiors that are absolutely useless without airconditioning.
