American Institute of Certified Planners (AICP) Practice Exam

Roadway delays per vehicle between 40 and 60 seconds would define a Level of Service of?

1. LOS A

2. LOS C

3. LOS D

4. LOS E

The correct answer is: LOS D

A Level of Service (LOS) designation provides a qualitative measure of traffic conditions and the service quality experienced by drivers on a roadway. The categories range from A to F, with A indicating optimal conditions and F representing severe congestion. In this scenario, a roadway delay per vehicle ranging from 40 to 60 seconds falls within the criteria that typically characterize LOS C. At this level, traffic flow is stable, but there may be a noticeable increase in travel time and a minor reduction in freedom to maneuver compared to LOS A and B. Although vehicles can operate effectively, drivers may experience some delays, highlighting a transition from free flow to conditions that begin to be impacted by higher traffic volumes. LOS C is often defined by travel speeds that are significantly reduced compared to free-flowing conditions, with average delays per vehicle that reflect moderate congestion. Understanding these nuances helps planners and engineers assess roadway performance and implement appropriate improvements to maintain or enhance service quality.