在香港，我们在街道的另一边开车。

I would say, "我们在香港的驾驶方向是相反的". To put it more precisely, I would say "我们在香港的驾驶方向是左上右落的. “左上右落”, literally "left up, right down", means "drive/walk on the left". In HK, "靠左行驶" means to drive in the leftmost lane, i.e. the slow lane., or to keep to the left. These wordings are applicable in HK. They may be different in other Chinese speaking regions.

Exactly 彭老师！ 在香港开车都是靠"左"行驶 sounds more natural and idiomatic. other side = 另一侧/另一边.

Maybe something like 我們在香港開車在路左邊 Not entirely sure if this is grammatically accurate, but it says driving on left side of the road rather than "other side". I'm not quite sure how to say "otherside", maybe 別邊？