Passenger miles per gallon
Passenger miles per gallon (PMPG) is a metric to evaluate the energy efficiency of a vehicle or transportation mode. The PMPG can be obtained by multiplying the miles per gallon of fuel (MPG) by either the passenger capacity or the average occupancy. The occupancy of personal vehicles is typically lower than capacity by a considerable degree  and thus the values computed based on capacity and on occupancy will often be quite different.
- "US Railroad Passenger Miles Per Gallon". Archived from the original on March 15, 2007. Retrieved May 2, 2007.
- "Example calculations (Colorado State Exam)". Retrieved May 2, 2007.
- "Vehicle Occupancy per Vehicle Mile by Daily Trip Purpose". Retrieved May 2, 2007.
- "Vehicle Occupancy Per Vehicle Mile by Time of Day and Weekend Status". Retrieved May 2, 2007.