My truck hasn't been delivered yet. When it gets here I plan on doing the Styrofoam test...That's what I call it!

I placed several Styrofoam coolers (boxes would've worked just as well) in the street on the cul-de-sac by our house and backed up to them at different angles and approaches. Stopping at different distances, getting out and actually looking to determine what the different colored lines represented in actual feet and or inches. It really helped understand how to determine through the fisheye lens what was directly behind or off to the sides and how far I actually had before damaging my Mustang.

Feels like grade-school but it works for me.