vehicle for transporting prisoners
轞 centers on a vehicle specifically designed for transporting prisoners, combining the idea of a cart with confinement or supervision.
轞 combines 車 (vehicle) with 監, which likely contributes both sound and the idea of supervision or enclosure, together suggesting a cart for guarded transport.
A cart (車) with a supervisor or guard (監) on board: this is a vehicle for moving prisoners under watch.
For カン, picture a can-shaped prison cart rolling along: can -> カン, and the prisoners are inside the can-like vehicle.