American Institute of Certified Planners (AICP) Practice Exam

Roadway delays per vehicle between 15 and 25 seconds would indicate what Level of Service?

1. LOS A

2. LOS C

3. LOS D

4. LOS E

The correct answer is: LOS A

Level of Service (LOS) is a qualitative measure that evaluates the performance of a transportation system, especially roadways, based on factors such as speed, travel time, and delays. In this context, a delay of between 15 and 25 seconds per vehicle typically indicates a higher level of service. LOS A denotes free-flowing conditions where vehicles experience very minimal delays, usually less than 10 seconds per vehicle. As delays increase, the level of service decreases. In contrast, levels such as LOS C, D, and E reflect increasing levels of congestion and delays that significantly affect travel. Specifically, LOS D reflects significant congestion with delays typically over 30 seconds, and LOS E indicates very congested conditions nearing capacity with high delays. Given that 15 to 25 seconds per vehicle represents a moderate amount of delay that does not substantially detract from the free-flow experience typical of LOS A, it aligns more closely with the characteristics of LOS A, especially as the threshold for LOS B and C is generally higher than 15 seconds. Thus, identifying the correct level of service for the given delay range at the lower thresholds reinforces the notion that the road is functioning fairly well, making LOS A the correct selection for this scenario.