If the only thing keeping you awake at the wheel is having the radio on, rather than driving you should be having a break (for some people, a coffee and a micro-nap will work wonders).

Agreed, if it's the only thing keeping you awake, but plenty of people find it easier to concentrate on a task if there is also a "distraction". It's like when school children fiddle with a pen to help them concentrate. The teacher might think it's a sign that they're not paying attention, but actually it's enabling them to pay attention.

I see it as a scale, where having the radio on or not could push a few point more regarding engagement in the task.

The same way someone shouldn't be driving if they're dead tired, but even if they're in an alert state, drinking a cup of coffee can sharpen them a bit more.

This seems to me no more than a bunch of justifications. I live in a region with -40°C winters and +40°C summers (that's the extremes, but we see them every year, and the averages are not far off). Most people drive without air conditioning in summer and with just enough heating in winter to make the air tolerable in several layers of heavy clothing. It's fine.

We all have our anecdotes, so to try get a bit of distance on how well people deal with heat:

> Results show a significant positive association between fatal traffic crashes and heat waves with a 3.4% (95% CI: 0.9, 5.9%) increase in fatal traffic crashes on heat wave days versus non-heat wave days.

https://www.sciencedirect.com/science/article/abs/pii/S00014...

Doesn’t look fine to me.

Sounds like a lot of people are fiddling with their AC settings and causing accidents.