IC 9-18.1-2-4: Semitrailer or trailer used with apportionable vehicle; exception

Sec. 4. A semitrailer or trailer that is used in combination with a vehicle that is an apportionable vehicle under the terms of the International Registration Plan may be operated on a highway if the semitrailer or trailer is registered in accordance with the laws of a jurisdiction that participates in the International Registration Plan.