There's an important detail that ogb started to talk about. There is more
than one kind of car seat. For a new born baby who doesn't have neck
strength, the rear facing seats have a thing that goes around the baby's
head to keep it from rolling around too much. Properly strapped into one of
these infant seats, I dare say you can throw it a distance without injuring
the baby inside. On the other hand, hand carrying a baby in a car means in
case of an accident, the baby can (probably will) become a projectile that
flies around the inside of the car (injuring every passenger) or fly out
through the side windows or the wind shield. A properly installed car seat
will hold the baby better than his superhuman mommy.
The same actually apply to a stroller. You need an appropriate stroller for
your baby or it's no better than a wheel barrel (the thing to carry dirt).
Again, the stroller should probably keep the baby reasonably safe if it
falls down the stairs.
For reference, I have a rear facing infant car seat that attaches to a
stroller that I almost never use (it's snowy). The baby will continue to
ride in the car seat on top of the stroller until the baby meets the
specifications of the stroller.
Keep up the safety conscious lifestyle everybody
