What is the effect of increasing lane width on Free Flow Speed?

• A. It generally decreases Free Flow Speed
• B. It has no effect on Free Flow Speed
• C. It generally increases Free Flow Speed
• D. It only affects heavy vehicles

Answer: (C)

Increasing lane width typically leads to an increase in free flow speed on a roadway. This is because wider lanes provide drivers with more room to maneuver, improving overall comfort and reducing the likelihood of sideswipe accidents. It enhances driver perception of space and can lead to more efficient traffic flow as vehicles can travel more freely without the constraints that narrower lanes can impose.

Wider lanes also enable drivers to maintain higher speeds safely as they feel less confined and are less prone to making frequent lane changes or adjustments. In essence, with improved lane width, the psychological and physical comfort experienced by drivers promotes increased speeds, thereby raising free flow speed.

While heavy vehicles may have specific considerations regarding lane width, the general impact of wider lanes leads to an overall increase in speed for all vehicle types.