American Institute of Certified Planners (AICP) Practice Exam

What does a Level of Service (LOS) of "C" at a signalized intersection indicate?

1. Uncongested operations

2. Significant congestion

3. Light congestion, occasional backups on critical approaches with an average delay of 15-20 seconds

4. Free flow of traffic

The correct answer is: Light congestion, occasional backups on critical approaches with an average delay of 15-20 seconds

A Level of Service (LOS) of "C" at a signalized intersection indicates light congestion, which may result in occasional backups on critical approaches. At this level, drivers can expect an average delay of 15 to 20 seconds during peak traffic conditions. This designation suggests that while traffic flow is generally acceptable, conditions are beginning to become constrained. When traffic volume approaches the capacity of the intersection, the efficiency of movement is still reasonably maintained, but it's not optimal. The presence of slight delays and backups highlights that the intersection is functioning, but users should anticipate longer wait times compared to a more efficient LOS. Understanding this benchmarks traffic conditions helps planners assess the operational effectiveness of intersections and identify when improvements might be necessary to mitigate delays or enhance network performance.