Since when are the MBTA Transit Police allowed to make traffic stops on Huntington Avenue? Spotted at ~10:10, between South Huntington and Mission Hill (nowhere near a bus stop or any other MBTA property, and no buses or trolleys in sight, either): male and female officers from one of the "wagon" Transit Police units, inspecting the license of a driver and speaking to her.

A little background on how complicated Chapter 90 authority can be.