A Washington Attorney General Opinion in 1984 determined that riding with a child as a passenger on a motorcycle under 5 years old was unsafe and therefore illegal. This decision was made in part because child safety seats are required in cars and motorcycles do not have similar restraint options.
Until adequate child restraint devices for motorcycles are at some time developed, and then approved for use in this state by the State Commission on Equipment, it is, therefore, illegal for the parent or legal guardian of a child under five years of age to transport that child on his or her motorcycle, just as it would be illegal for them to transport their child in their automobile without an approved device.
Every state has a child safety restraint law for children riding in motor vehicles such as cars and trucks. Almost all states (all save New Hampshire, Illinois, and Iowa) have safety helmets required for riders, including many states with motorcycle helmet laws only for youthful riders (under 18 or 21 for example). Despite that, only two states have motorcycle passenger age restrictions, Washington and Hawaii (prohibits riders under 7 years old).
Although this issue effects only a small number of children, as many riders do not take young children as passengers or at least place them in sidecars, not all parents understand the significant risk of harm to a child that a motorcycle accident presents. Even the best rider knows that a driver who does not see them can quickly end their life. A child who is not able to intelligently make the decision to ride or not should not be forced into such risky situations because of their parent’s beliefs. See these discussions: one parent painted a bicycle helmet and considered it safe enough for his baby who rode in a sidecar, another mom allowed her son to ride regularly with his dad since he was 3 years old.
I have been riding motorcycles since I was 16 years old. I always wear a helmet and would not allow anyone under 16 to ride as a passenger with me and will not take a passenger without a helmet. These are personal preferences, but I firmly believe in protecting young children from harm because of their parents’ decisions. The issue of motorcycle passenger age restrictions is ripe for statutory change.
More information on national motorcycle laws can be found in this National Motorcycle Law Chart.