The 65 Fairlane is analogous to a single family residence.  When you take it for a ride, you are putting just your family at risk.

If the Fairlane could carry the same number of people as Marco Polo - 586 units x 2 people per unit = 1,172 people, then it would be analogous to a high-rise.  Therefore you could be jeopardizing a lot more than just your family.  Then you might be forced to install air bags due to the higher occupant load or not allowed to drive it with all of those passengers.

Building codes have different rules for high-rise and single family residences because of the number of people would can be in the building at the same time.