I guess I mean we have lighting laws or maybe standard is the proper term for NorthAmerican lighting with various US SAE and Canadian motor vehicle SAE regulations for headlight design /aiming. A company I worked for used to work with headlamp and tail lamp data and had a light testing tunnel.

But you throw in a bulb with the wrong focal length for your cars parabola and you get splayed light in all directions instead of a parallel aimed beam. In Ontario a law governs improper headlight aim, but I have rarely seen anyone get a ticket