Though discussions of vehicle efficiency are often centered on a measurement of miles per gallon, it is also important to consider how efficiently a vehicle carries its payload. Although heavy vehicles like buses or class 8 trucks get much fewer miles per gallon than cars, a greater percentage of their mass is payload which means that they are much more efficient at carrying weight whether passengers or cargo. The figure below shows that as the size and mass of a vehicle increases, so does its' efficiency in moving freight. When fuel efficiency is measured in gallons of fuel per thousand ton miles, a car consumes 69 gallons of fuel while a school bus consumes about 20 gallons and a class 8 truck consumes just six and a half gallons.
Freight Hauling Efficiency by Vehicle Type
|Class||Applications||Gross Weight Range|
|Typical Fuel Consumed|
(gallons per thousand
|1t||Minivans, Small SUVs, Small Pick-Ups||4,000-6,000||58.8|
|2a||Large SUVs, Standard Pick-Ups||6,001-8,500||38.5|
|2b||Large Pick-Ups, Utility Van, Multi-Purpose, Mini-Bus, Step Van||8,501 -10,000||38.5|
|3||Utility Can, Multi-Purpose, Mini-Bus, Step Van||10,001-14,000||33.3|
|4||City Delivery, Parcel delivery, Large Walk-in, Bucket, Landscaping||14,001-16,000||23.8|
|5||City Delivery, Parcel Delivery, Large Walk-in, Bucket, Landscaping||16,001-19,500||25.6|
|6||City Delivery, School Bus, Large Walk-in, Bucket||19,501-26,000||20.4|
|7||City Bus, Furniture, Refrigerated, Refuse, Fuel Tanker, Dump, Tow, Concrete, Fire Engine, Tractor-Trailer||26,001 -33,000||18.2|
|8a||Straight trucks, e.g., Dump, Refuse, Concrete, Furniture, City Bus, Tow, Fire Engine||33,001 -80,000||8.7|
|8b||Combination trucks, e.g., Tractor-Trailer: Van, Refrigerated, Bulk Tanker, Flat Bed,||33,001-80,000||6.5|
Source: Oak Ridge National Laboratory, 2011 Vehicle Technologies Market Report, Oak Ridge, TN, ORNL-TM-2011/016, February 2012.