Historically, it might be because the T (the Boston Subway) doesn't run 24 hours, it shuts around 1am, so most people have to make arrangements to get home well

Historically, it might be because the T (the Boston Subway) doesn't run 24 hours, it shuts around 1am, so most people have to make arrangements to get home well before then or risk having to take a pricey cab home.