Are all the bulbs in street lighting connected in series or parallel?

They are connected in parallel. The voltage for every one of them is the same as the total voltage. If they are connected in series, once one light breaks down, the whole line of street lights will be influenced. To reduce this influence and ensure sufficient street lighting, the lights are connected in parallel. Even in parallel, they can still light up at the same time.

المزيد من القراءة: ما هو ضوء الشارع الذكي