According to WWLP 22 News, warming up your car for more than 5 minutes while not being near or in it, is illegal in the state of Massachusetts since it's not a law regulated by any towns. Now it doesn't mean a police officer is driving around looking for idling vehicles because who has time for that honestly? It mainly has to do with the fact that you're putting yourself at risk of someone stealing your car or the exhaust possibly entering your home which causes carbon monoxide.
This building is no other than Boston City Hall located at 1 City Hall Square in Boston, Massachusetts. According to en.wikipedia was designed by Gerhard Kallmann, a Columbia University professor,[2] and Michael McKinnell, a Columbia graduate student[2] who co-founded Kallmann McKinnell & Knowles.
Governor Maura Healey just signed a new bill that cracks down on privately made, unserialized “ghost guns,” which will criminalize anyone is in possession of bump stocks and trigger cranks and will require applicants for a gun license to complete live-fire training.