Speed in traffic flow is inversely correlated with which traffic parameter?

Speed in traffic flow is inversely correlated with which traffic parameter?

• A. Queue Length
• B. Density
• C. Flow
• D. Traffic Volume

Answer: (B)

Speed and density move in opposite directions in the traffic flow relationship. When more vehicles occupy a segment (higher density), drivers must keep smaller gaps and slow down, so average speed decreases. Conversely, at low density there’s more space and speeds can be higher. This inverse link is captured in the fundamental equation q = k v (flow equals density times speed); as density grows, speed tends to drop, and flow increases only up to a point before falling again as speed becomes very low. Among the options, density is the parameter that shows a clear inverse relationship with speed. Queue length, flow, and traffic volume are related outcomes or defined differently (flow depends on both density and speed), so they don’t describe the direct inverse relationship.

Speed and density move in opposite directions in the traffic flow relationship. When more vehicles occupy a segment (higher density), drivers must keep smaller gaps and slow down, so average speed decreases. Conversely, at low density there’s more space and speeds can be higher. This inverse link is captured in the fundamental equation q = k v (flow equals density times speed); as density grows, speed tends to drop, and flow increases only up to a point before falling again as speed becomes very low. Among the options, density is the parameter that shows a clear inverse relationship with speed. Queue length, flow, and traffic volume are related outcomes or defined differently (flow depends on both density and speed), so they don’t describe the direct inverse relationship.