What is a primary function of interchanges?

The primary function of interchanges is to connect drivers to other highways. Interchanges are designed to facilitate the flow of traffic between different roadways without requiring vehicles to stop. This is achieved through the use of ramps and overpasses, allowing motorists to seamlessly transition from one highway to another. By enabling these connections, interchanges enhance mobility, reduce congestion, and improve safety for all road users.

The other options present various features or functions that are not associated with interchanges. Increasing toll fees is a policy decision related to funding roads but does not pertain to the structural purpose of interchanges. Allowing parking on the expressway goes against the intended design of such roadways, which prioritize through traffic. Pedestrian safety crossings are generally located in urban areas and not within interchanges, as the high-speed nature of highway driving makes them unsuitable for pedestrian access. Thus, the correct answer focuses on the vital role interchanges play in efficiently linking different highway systems.