Heavy Duty utility wall hook

I needed a strong hook to store my foldable hand truck in my van.
The hook needs to hold the hand truck in place while driving and prevent it from swinging when cornering or braking.
Offcourse the hook can also be used to store different things.

I printed 2 of these to hold the top (see photo). 
I also designed a small hook to hold the bottom of the hand truck, so it's stored even more secure.

I printed them in PETG with 15% infill. This way they are strong, yet still a bit flexible.
Other materials may work aswell.
Print the hooks on the side. This way the forces are spread over all of the layers, and the strength of the hook does not depend on layer adhesion.