This, along with a bungee cord, is what secures my recumbent trike in my mini-van when transporting the trike for a local ride. (This is different from transporting it folded between Washington and Arizona). This anchor is screwed to the custom plywood floor of my car, behind the passenger seat. Attached to it but not visible here is a bungee cord that is lying on the floor.

When loading the trike, I push it up the ramp (shown in other photos) and wheel it forward until the right front wheel slides into the slot and touches the end board. Then I pull the bungee cord and hook it onto the rear of the trike, which keeps the trike tight against the end board. Trike secured!

Unhooking the bungee cord releases the trike for removal from the car.