How is average spot speed related to time mean speed?

• A. They are equivalent terms in traffic analysis
• B. Average spot speed is a more precise measurement
• C. Time mean speed applies only to highways
• D. Average spot speed is specifically for analyzing capacity

Answer: (A)

Average spot speed and time mean speed, while often used in traffic analysis, are not equivalent terms, as they are derived from different methods of data collection. Average spot speed refers to the average speed of vehicles passing a specific point on a roadway over a given time period. It is a direct measurement of speed at that point, providing insight into the behavior of drivers at that particular location.

On the other hand, time mean speed is calculated as the average of individual speeds measured over a certain time period at various points, considering the duration of time that vehicles are present on the roadway. This measurement gives an overall impression of the traffic flow on the road section but does not focus on a single location.

The distinction between the two lies in their use and applicability. While average spot speed can provide precise data for traffic operations at specific locations, time mean speed reflects the average speed of all vehicles on a stretch of roadway over time, accounting for vehicles that might not be observed passing by the measurement point.

The other options suggest specific advantages or contexts for each type of speed that do not accurately depict their true nature or application in traffic analysis. For example, stating that average spot speed is more precise (as suggested in one of the options) overlooks the broader context in