https://wiki.openstreetmap.org/wiki/United_States/2021_Highway_Classification_Guidance

These are the new guidelines. Under state specific guidelines, Massachusetts has a classification standard.

MassGIS F-Class 2 = highway=trunk
MassGIS F-Class 3 = highway=primary
MassGIS F-Class 5 = highway=secondary

Here is the page from MassGIS that provides the data:

https://wiki.openstreetmap.org/wiki/United_States/2021_Highway_Classification_Guidance
