There's a lot of weird things going on in this video. The target audience seems to be kids and people of color. The kids part I understand, but Boston is a predominantly white city and as far as I've seen and read, it's mostly white people that get killed in jaywalking accidents and many of those people are students from outside of the area who think they know how to jaywalk.
I argue that jaywalking is a skill that needs to be honed, if one is to get anywhere by walking in the Boston area.
Anyway, I don't understand the thought process behind this video.
My guess is that some non-profit, interest group, community org, or estate that's associated with one of those target groups left money for the purpose of safety and public outreach. The MBTA decided that a fun way to use it and educate the public was a video. I think they're drawing inspiration from Dumb Ways to Die, another large metro transit authority's catchy safety PSA. I don't know if they seriously expected anybody to consciously change their behavior as a result of this, but just subconsciously. And hey, it's better than a boring old PSA, cause they got you to click on it, didn't they?