Frankford, MO unknown distance

I’ve come across a few cities that know how many streets but don’t know how many miles of streets that is. Frankford is an example: Frankford, Missouri - CityStrides

I assume this is because of bad data on OSM, but I’m not even sure what would need to be updated. OSM knows that the town exists, and apparently streets that reside in the boundary, so what would need to be done to measure those streets?