Lap belts should work for an infant seat
Infant seats are rear facings and usually the base gets secured.
Lap belts alone will Not work for a forward facing car seat and probably not legal in most states. forward facing Car seats require a latch system, or lap belts and center top latch or hook.
Once the kid out grows the car seat they will use a booster seat for a short while.
A Booster seat is not legal with lap belts.
Check your state laws and requirement for the child seat you purchase.
