Trailer Widths and Lengths --the law in Michigan
It has been unclear to me up until now exactly how wide a tiny house on a trailer can be. I'd read in enough places that the normal width limit is 102" (8' 6") that I'm comfortable with that (plus that's the max width trailer you can buy), but my concern was with the eaves. A house with a roof that ends flush with the exterior siding of the house, with absolutely no overhang, looks weird. It looks wrong. But it would be even more wrong to limit the width of a house by the width of the furthest piece sticking out, such as a windowsill or a doorknob, and make the floor space smaller. I hadn't found a decisive explanation, so I searched for the actual law. For Michigan, it's MCL 257.717. This section of the law also sets the limits for the height, length and weight of a trailer. There's probably a similar law in most states, but in some the width may be a little more or a little less.
IANAL. but as I read it, I should be allowed a 6" eave on either side of my house.
(5) The total outside body width of a bus, a trailer coach, a trailer, a semitrailer, a truck camper, or a motor home shall not exceed 102 inches. However, an appurtenance of a trailer coach, a truck camper, or a motor home that extends not more than 6 inches beyond the total outside body width is not a violation of this section.
Once again, I Am Not A Lawyer, but I'm pretty sure an eave would be considered an appurtenance. As would windowsills and siding/trim.