This is a really not that much of a problem unless you have a compact sedan. I have 4 kids. You can fit 3 car seats in the back/middle row of many cars. They ma

This is a really not that much of a problem unless you have a compact sedan. I have 4 kids. You can fit 3 car seats in the back/middle row of many cars. They make narrow seats for this purpose. In my experience it’s harder to find a good narrow booster than a narrow five-point-harness car seat. The problem is that boosters don’t have their own belts and can block the seat belt path if seat spacing is tight.