I got this at a local pet shop. Tede sits hi up, so he can look out. In the truck it fits in the front. But most of the time it sits nicely in the back seat of a car. He loves to look and bark at every thing that moves.
or some time we fit it in the middle of the back seat so he can look over our shoulders and beg for treats. I have seen them on line. They are a tall foam padding, with a fluffy covering. sorry I dont have the name. when he goes with us he loves to sleep in it.
heres a pic. hope this helps
and there are hook ups so it hooks to a harness