According to Harav Yosef Sholom Elyashiv zt"l: (Ashrei Ha'ish)
Lighting a Chanukah Menorah in front of the City Hall, Parliament
buildings, top of cars or other public places etc. makes no sense
whatsoever, even if your intention is to publicize the Neis
Chazal instituted פירסומי ניסא, when, where, and how.
Anywhere else, there is absolutely no Mitzvah to do.
Those who light there with a ברכה are עובר on a ברכה לבטלה"