Is it possible to have three seats for young children (18 months to six years old) properly secured in a large family estate car? My son would rather not buy a people carrier or SUV, but is concerned whether three children’s seats can be properly secured across the back seat of an estate car, as the central seat belt is usually just a lap belt, and the total width of the back seat might not be enough. Are some cars better than others for fitting three children’s seats?