Car Seats

My son is 27 months old, weighs 29.5lbs, and is approx. 35-36inches tall. is he big enough for a booster seat yet, or should i keep him in his car seat for awhile longer?just wondering, because my nephew will be three years old in april, only weighs about 4 lbs more than my son and is approx. 5inches taller, and has been in a booster seat for about six weeks now.

Carseat definitely. go to this website, and input his information to find out when he can move into a booster seat: http://www.boosterseat.gov/