Can anyone explain the 2 hour car seat rule to me?

I know that young babies should not be in a car seat for longer than 2 hours but I don’t fully understand why. Of course there is the risk of positional asphyxiation in a car seat but could that not happen in less than two hours? Is this the reason for taking them out every 2 hours or is it more so to let them stretch so they aren’t in an uncomfortable/damaging position for too long?Also, when a baby is taken out of the car seat for breaks on a long drive, is there a rule on how long they should be out for?I’ve heard the rule as no more than two hours a day but also no more than two hours at a time, so which is it?When can an infant safely be in a car seat for longer than two hours? I’ve heard three months but also 6 months.For context, I live about three hours from the nearest major city and would love to take the occasional trip there to bring LO to events/attractions that aren’t offered locally for us. My husband and I also enjoy road tripping and would of course love to bring our LO along someday. I just want to make sure it is safe to do so if/when we attempt it. via /r/NewParents https://ift.tt/U2i8x5G