passenger miles

Passenger miles measure the total distance traveled by all passengers on a transportation system, combining both the number of passengers and the distance each travels. For example, if 100 passengers each travel 10 miles, that totals 1,000 passenger miles. It’s a useful way to gauge the overall usage and efficiency of transportation services like airlines, trains, or buses, by reflecting how much travel is happening in total. Passenger miles help compare different systems or routes based on how heavily they are used.