Sec. 15. (a) This section does not apply to a person who drives a motor vehicle in a vehicle platoon with respect to another motor vehicle in the same vehicle platoon.
(b) Except when overtaking and passing, a person who drives a motor truck, motor truck drawing another vehicle, or tractor-trailer combination, when traveling upon a roadway outside of a business or residence district or upon a roadway that is a part of the interstate highway system, whether within or without a business or residence district, may not follow within three hundred (300) feet of another motor truck, motor truck drawing another vehicle, or a tractor-trailer combination.