In my local county, Baltimore County, population 800k, a decision was made to also strip all punctuation from official county address data and from all signage. The following rules were applied
- Any possessive apostrophe, e.g. Elliott’s Road, would simply drop the possessive apostrophe, e.g., Elliotts Road.
- Any hyphen was dropped for a space
- Any other apostrophe was dropped and the word would be smashed together. There are only two instances of this: L’Hirondelle Rd (French) became LHirondelle Rd on signage and M’Lady Rd (think, ‘my lady’, medieval style) became MLady Rd.
Since OSM follows what the signs say, or what’s observed, I think it would best to model these based on how the local jurisdictions decide to sign their streets. I believe FHWA guidance is to have mixed case signs (Elliott Road not ELLIOTT ROAD).