Why do school buses and lorries have wider tyres compared to bicycles?

Here's the answer to question 2.

2. Why do school buses and lorries have wider tyres compared to bicycles?

School buses and lorries are significantly heavier than bicycles, meaning they exert a much larger force on the ground. To prevent them from sinking into the road and to ensure stability, they use wider tyres. Wider tyres increase the surface area of contact with the ground. By increasing the area, the pressure exerted on the road ($P = F/A$) is reduced, distributing the heavy load more effectively. Bicycles, being much lighter, do not require such a large contact area.