I also like making the most of the opportunity of sitting still without the need to 'do' anything when travelling in the car (when not driving, of course). If I know that I have to travel, I usually pack my crochet. I find that crochet doesn't need any patterns or a lot of materials and isn't too tricky to do whilst bumping along the road.
As we have recently spent time travelling, I managed to whip up quite a few crochet flowers.
I hope you have had the opportunity to enjoy some crafting!