I've searched a bunch of different forums, and I've seen tons of writeups on how to install the cab top clearance lights, but I've never seen the why of them....

Is there a functional reason for the things, or is it just because they look cool? Don't get me wrong, I'm not at all ragging on people for adding something to their trucks just for looks..just purely curious.

 

Mainly for looks. But as with any lights, more are going to make you more visible at night though I highly doubt that most people want them for that reason. They are required by law on duallies.

 

They were originally used for clearance lights, the highest point on the vehicle, hence the name. They are required on dually's b/c the cluster(center 3) are required as an identifier on all vehicles, or trailers in tow, that are i believe 101" and wider. May have to recheck the exact measurement, but I know it's a width restriction.