Best to measure your car seats and you will be surprised what can fit 3 car seats.

We have 3 Babylove Ezy Combo seats (does from 6mths to 7yrs) across the back seat of our VY Commodore Station Wagon with room on the edge of the seats so they are clear of the doors, and we also have 3 smaller car seats that do up to 4 yrs in the back seat of our 3dr Hyundai Getz