Car seats! Properly securing an appropriate car seat is vital to the baby's safety. Safe driving practices are obviously essential too! The size of your vehicle is a factor in car safety as well, but this is not specific to your baby.
Face rear. While traveling, infants should ride facing the rear until they are at least two years of age. A convertible car seat with a rear facing weight limit of 30+ pounds is a great investment. Infants can flip a car seat off a table or bench, so put them on the floor if not in use. The majority of child injuries in vehicles occurs within 30 minutes of home, so use the safety system every time.
Car seat. Car seat installed properly.