What is the time-mean speed in traffic flow?

The time-mean speed in traffic flow is indeed best represented by the average of speeds for all vehicles at one location. This concept is significant in traffic engineering as it reflects the average speed of individual vehicles over a specific period as they travel past a particular point. By considering all vehicles and their respective speeds during that time frame, it provides a comprehensive measure of traffic conditions at that specific location.

This method accounts for variations in speed across different vehicles, allowing for a more nuanced understanding of traffic flow dynamics. For example, if the average speed of various vehicles fluctuates due to traffic signals or congestion, the time-mean speed gives a clear representation of how traffic is performing at that location.

In contrast to other options, such as the average of speeds over a specific time or the speed of the fastest vehicle, these choices do not capture the broader context needed to assess traffic conditions uniformly. Similarly, dividing total distance by total time is more aligned with calculating average speed rather than focusing specifically on the individual speeds of vehicles at a given location.