In this pic, Rebecca demonstrates that in the event of an emergency on board the bus, the green lights on the top and backside of the bus will flash and the destination display will display "EMERGENCY" and "CALL MBTA POLICE". It's important that us MBTA passengers report these to our local MBTA Transit Police when we see it. Bus-related emergencies come without warning. So please be prepared. I know i'm always prepared to report if I see things like this when I come to Boston. Click download to access the animation. The reason I did this one is 'cause FA user lunden asked me what those green lights on the top of the bus are for, so I eventually decided to do this pic, demonstrating those green emergency lights.