https://en.wikipedia.org/wiki/Cant_(road/rail)
“Along straight or gently curved sections, the middle of the road is normally higher than the edges. This is called ‘normal crown’ and helps shed rainwater off the sides of the road.”

“Cross slopes of this size, especially when applied in both directions of travel with a crown point along the centerline of a roadway are commonly referred to as ‘normal crown’ and are generally unnoticeable to traveling motorists.”
https://en.wikipedia.org/wiki/Geometric_design_of_roads#Cros...