Daily passenger kilometers
This is the sum of kilometers traveled by all passengers each day, and is a measure of the use of the bus system. When divided by the total passenger-place-kilometers it will give the average load factor.

Where a graduated fare scale is used, with distance traveled directly related to the fare paid, total passenger kilometers can be estimated from the total fares paid. Where flat or zonal fares are used, this statistic must be obtained by means of surveys.