What is the reason for the curves and slope on entering a expressway?

The curves and slopes on entering an expressway are designed to facilitate a smooth transition for vehicles merging from a slower road to higher-speed traffic. The curvature helps guide drivers safely onto the expressway while maintaining a comfortable turning radius, reducing the risk of skidding or losing control. The slope, often referred to as a "superelevation," helps counteract lateral forces during the turn, allowing vehicles to maintain speed and stability as they merge. These design elements enhance safety and traffic flow on the expressway.