A booster seat is a type of pet seat where you can strap on a car seat’s headrest, providing extra height and leverage to your dog. This is normally available for smaller dog breeds as it can handle only a limited amount of weight. Likewise, smaller pets can be able to see outside the window and decreasing the occurrence of car sickness.
On the other hand, the usual pet car seat can be placed in front or back seat. It usually has no straps. Instead, the dog simply plops inside the car seat and make himself comfortable during the ride. Some pet seats have built-in belts where you can strap your pet in it, hence adding extra protection while on the road.