Passengermile

Passengermile, more commonly written as passenger-mile or passenger mile, is a unit of measurement used in transportation to quantify the amount of travel by passengers. One passenger-mile represents the movement of a single passenger over a distance of one mile. The metric version is the passenger-kilometer (pkm), where one pkm equals one passenger traveling one kilometer.

Calculation and scope: To determine total passenger-miles for a service or system, multiply the number of passengers by the distance each passenger travels and sum across trips. For journeys with multiple segments, passenger-miles are typically accumulated for each segment. This metric can be applied to a single vehicle, a complete transit network, or an entire mode (cars, buses, trains, airplanes), and is often used to compare usage, demand, and efficiency across modes or routes.

Applications: Passenger-miles are used to analyze energy intensity and emissions per unit of travel, assess service effectiveness, and support capacity and demand planning. Related measures include revenue passenger miles (used in aviation and rail), available seat-miles, and passenger-kilometers. The metric enables comparisons of performance across different transport modes and helps normalize outcomes by usage rather than simply by vehicle count.

Limitations: Passenger-miles do not capture travel time, comfort, cost, or trip quality. They can be influenced by occupancy fluctuations and routing patterns, and may obscure differences in service reliability or accessibility.

Example: If 100 passengers travel 10 miles, that journey accounts for 1,000 passenger-miles (100 × 10).