The speed at which an individual vehicle travels over a highway section is known as its running speed. Running speed is calculated by dividing the length of the highway section by the time for a typical vehicle to travel through the section. For extended sections of roadway that include multiple roadway types,

the average running speed is the most appropriate measure for evaluating level of service (LOS) and road user costs.

The average running speed is the sum of the distances traveled by vehicles on a highway section during a specified period of time divided by the sum of the travel times.

The average running speed on a given roadway varies during the day, depending primarily on the traffic volume. Therefore,

when reference is made to a running speed, clearly state whether this speed represents peak hours, off-peak hours, or an average for the day.

It is most appropriate to use peak and off-peak running speeds in design and operation. Average running speeds for an entire day should be reserved for economic analyses. The effect of traffic volume on average running speed can be determined using the procedures of the .