Your scenario about Westfield State or ANY college PD for that matter can stop cars for criminal M/V violations on public ways that adjoin or connect campus facilities. That is via Commonwealth v. Smeaton, 465 Mass. 752 (2013). I remember that case being announced at roll call when it was decided so we all knew to expect campus cops doing M/V stops on the streets around their campus and to back them up.Trying to get something cleared up. Maybe their is a reason why state campus PDs are sworn in under MGL Ch 22C section 63 is because of the of the language "upon lands or structures owned, used or occupied" and that is not in MGL 73-18.
Lets say Westfield State campus police, got rid of their SSPO appointment and just used 73-18. Say they make a car stop on Western Ave as it is used to reach property of their campus. They stopped a car for OUI which is allowed under the SSPO language. Would that same stop be allowed under 73-18 since there is no "used" language in that statue.