When we do our long vacation drives the bikes and wheels are in the bed of the truck or inside the SUV. When actually driving (moving) that is not an issue, but when we stop, the heat rises quickly inside. I have gotten in the habit of airing down when we travel. We will not be riding enroute, so I air down to prevent heat related blowouts. Only had it happen once, but I heard it from inside the restaurant where we stopped for lunch. Fortunately, I had the bikes covered with a light tan canvas painters tarp and had left the windows cracked for some ventilation, as I have heard (anecdotally) that it could have blown out the glass. When we checked the bike, the rims were very, very warm as were the tires. It was the rear (a bit more pressure) that blew, the front could not be dented with thumb pressure, and fortunately if blew off without damaging the case or bead. That was back when I used 25mm tires and higher pressures.
For that same reason, I would not leave CO2 cartridges, canned air, lithium batteries, etc. inside a hot car. We will put that type of item in a small lunch cooler.