What are you trying to reach for? Western Ave by Highland Elementary, or maybe up at the Bates Road split? Ask your supervisor dude. This is an annoying "what if" question that has ten answers and most of them guesses. As pointed out there are probably a dozen case laws covering this. SSPO don't get you nothing special. OUI is OUI under Chapter 90. It's always up to the courts have fun.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.