Which of the following factors influence the free-flow speed of a basic freeway segment?

• A. Track conditions and vehicular age
• B. Lane width, lateral clearances, total ramp density
• C. Vehicle type and weight distribution
• D. Weather conditions and traffic signals

Answer: (B)

The free-flow speed of a basic freeway segment is significantly influenced by factors related to roadway geometry and traffic characteristics, which are well represented by lane width, lateral clearances, and total ramp density.

Lane width plays a crucial role in determining how comfortably vehicles can maneuver. Wider lanes typically allow for higher speeds due to better vehicle stability and less likelihood of collisions. Lateral clearances, which refer to the space available between vehicles and obstacles, also contribute to driver comfort and perceived safety, leading to faster speeds. Finally, total ramp density affects how easily vehicles can enter and exit the freeway. More ramps can disrupt the flow of traffic, but if well-designed and spaced, they can enhance accessibility without significantly impeding speed.

While other factors listed, such as track conditions, vehicular age, vehicle type, and weather conditions can also affect speeds, they are more secondary influences compared to the geometric characteristics of the roadway itself. Traffic signals pertain primarily to urban environments and are not applicable to freeways designed for uninterrupted flow. Thus, the importance of lane width, lateral clearances, and ramp density in influencing free-flow speed makes this answer the most relevant in the context of freeway operations.