Just to kill my curiosity, what's the story behind this video?
I see that you're near the entrance or side entrance of the Willard InterContinental Washington [wikipedia] in Washington D.C and judging by the decoration it seems to be near Christmas times and there is going to be some kind of event at the hotel in question.
I had never heard about US Park Police (USPP) [wikipedia] prior to watching this video. Apparently it has it's roots in District of Columbia and was created by George Washington in 1791 as the "Park Watchmen" to patrol federal property.