It could fit in the passenger side footwell of my SUV, but I kept it in the way back because I'd rather have my sweetie riding up front, and I also have an extra 12V outlet back there.
They do come in different sizes. Some have wheels. Mine is 18L and about 15 pounds, so wheels not necessary. Its about a mid to large size cooler shape. Not one of the ones you'd take deep sea fishing, but maybe a small tailgate. Think side handles cooler, not one where the single bar handle locks the lid in place.
I do not recommend rooting around in it while driving, though if I put it in my pickup on a solo road trip, I probably would put it on the front passenger seat, where if I were stopped at a red light, I could quickly grab another drink.
If you want me to PM you the link to mine, I'm happy to do so.