Comments here are siding with the M-22 company, saying things like “Let them do their thing.” No one is suggesting they should not be able to operate their business and produce their products exactly as they have been doing. What is being said here is that they have no right to prevent anyone else from using the Michigan DOT’s design on their products as well. The USPTO looks at millions of applications a year and as long as no one else has the same name, they rubber stamp it. They probably did not realize that is was a highway sign from the application, just something called M22. It is quite reasonable to expect a trademark examiner in Washington DC to not know M22 is a highway in Michigan. The Michigan Attorney General is quite correct to say that the trademark is invalid.
M22 is a brand name. A trademark may be valid for the brand. However, if they produce a coffee mug with the M22 DOT Highway Sign on it and market it as “M22 Brand Coffee Mug.” That is legit, and I cannot do the same thing. I can, however, make a coffee mug with the M22 DOT Highway sign on it and offer it for sale as “XYZ Brand Coffee Mug.”.