Replying to @mike_bowler@hachyderm.io
@mike_bowler I used to drive up and down California a few times a year, and I used to get tired and drowsy over the course of that drive, often needing to stop a couple times to get out and stretch my legs.
Yeah, you know where this is going.
On one drive I brought my CO₂ monitor, watched the number go up (it was past 1000 in under an hour), and realized what the problem was. Turned up the fan and watched the number go back down.
Never got drowsy on a long drive again.