Pulling a child out of a 5-point harness carseat wakes most kids. If something is keeping that kid from resting comfortably anyway (like pain), it would be even easier...
It's likely just the difference between different parenting experiences. I spent a good deal of teething days riding around bumpy roads 'rocking' my toddlers to sleep, the bumpier the better...as soon as my car stops, never mind unbuckling them, they are awake, same thing with hitting a smooth patch...so I didn't dare stop until they had gotten enough sleep, so definatley avoided roads with lights as well.
Sleep of course is the untimate cure for the crankies...absolutely not for pain, but it does take the edge off. A child that has any sort of head pain, that cries & fusses only serves to exaggerate it...so the goal...whatever keeps them quiet...just like distraction...perhaps the ability to play with other kids with new & different toys in a fun environment that captures the attention enough to 'forget'...
In terms of the time...I'm not at all suggesting that a bumpy ride is a cure for anything, except the crankies (aka overtired). I'm not assumign she slet the entire time, we don't know if she slept at all...I'm just saying that people are assumign this driving around sounds so hoaky, when to me it sounds like the perfect nap time...even an hour would be good, perhaps it took that long for her to relax...or maybe she drove for 60 minutes before she fell aslepp and she woke so Terri decided to take her to the gym hoping the other kids would wear her out enough for her to sleep at home...we know nothing.
I'm jsut saying at face value, to me, it sounds totally normal, well except if you are wanting to have an alibi for that time period, well, then, it's about as good as being home by yourself napping.