Hi Sebastian, please review these two wiki articles. The tagging convention in the US is to avoid using highway=motorway for very short segments of enhanced infrastructure where the portion that is enhanced to interstate standards is less than 2 miles and isn't otherwise part of the motorway network. In cases like Amherst's keeping the highway=primary and adding expressway=yes is the preferred tagging.

- https://wiki.openstreetmap.org/wiki/United_States/2021_Highway_Classification_Guidance 
- https://wiki.openstreetmap.org/wiki/Key:expressway

Please join us in the OSM Community forum's US category: https://community.openstreetmap.org/c/communities/us/78 or the OSM-US Slack's #highway-classification channel to discuss these topics.