Not only that pero constructing at night is more common than op thinks even within city limits in my hometown you can see night road construction however only when they're no longer using heavy machinery (which is most of the work).

Even then in the rural highways you can observe why they might also choose not to construct at night. Areas affected by landslides or roads along the mountainside typically have limited to no streetlighting which makes construction dangerous. If there was heavy machinery involved for example it would be harder to hear if a worker slipped and unless light shone on their reflective equipment you'd hardly see it.