What is the purpose of exit ramps on expressways?

The purpose of exit ramps on expressways is to facilitate a safe transition for vehicles leaving the highway. These ramps are specifically designed to allow vehicles to slow down in a controlled manner, making it easier for drivers to exit the expressway and merge onto local roads or highways without having to navigate at high speeds. The design typically includes a gently curving path that encourages a reduction in speed, which is crucial for safety considering the differences in speed between expressway and local road traffic.

In contrast, the other choices do not align with the primary function of exit ramps. While one might think of creating acceleration or merging lanes as part of highway dynamics, exit ramps specifically focus on providing a safe deceleration lane for vehicles exiting the high-speed environment of an expressway. Thus, the function of exit ramps is centered around safety and the management of vehicle speed during the exiting process.