An adjustable frame, mountable on a vehicle, for releasably securing hand trucks of different sizes and configurations includes: a support platform for receiving a base of a hand truck; a first and a second side member affixed to the platform; a first bracket and a second bracket attached to the first and second side members, respectively, the brackets extending in parallel therewith; an elongate swing bar pivotally connected to the first bracket and pivotal between a first position that retains the hand truck on the platform, and a second position, which allows access and removal of the hand truck from the platform; and a latch mounted on the swing bar. The second bracket may include a strike that engages the latch for releasably securing the swing bar in the first position. Cushioned crossbars attachable to the side members dampen vibration of the hand truck during transportation.