Highway curves are banked so the outside edge of the roadway is elevated above the inside edge. This provides additional centripetal force to keep the car on the road and following the proper path. The faster a car is moving, the more banking it will need.
Curriculum and Instruction | Engineering | Science and Mathematics Education
Hernandez, David and Steffen, Peg, "Activity 5: Slow Down, Curves Ahead" (2023). Theme 2: Around Town. 5.