Do your DOT MC numbers have to be a certain size?

I am leased onto a company and will pick my own stickers and wondered if there is a certain size limit to how small they can be? I imagine they have to be large enough for the guy sitting at the weigh station to see. I plan to add them to the sides of my sleeper. Is there a particular font size you recommend?

 

2 inches in height?

 

So I suppose I can fit all of that on my sleeper panel door. I need four lines and there is space at 2 inches each line.

 

Oh one more question I remember back when I was in Colorado they would have me come in the weigh station since my VIN wasnt on the truck. How many of the last VIN number do they like to have?

 

To you?