This document describes a rigorous-engineering fuel-consumption test procedure that utilizes industry accepted data collection and statistical analysis methods to determine the change in fuel consumption for individual trucks and buses with GVWR of more than 10000 pounds. The test procedure may be conducted on a test track or on a public road under controlled conditions and supported by extensive data collection and data analysis constraints. The on-road test procedure is offered as a lower cost alternative to on-track testing, but the user is cautioned that on-road test may result in lower resolution (or precision) data due to a lack of control over the test environment. Test results that do not rigorously follow the method described herein are not intended for public use and dissemination and shall not be represented as an SAE J1321-Type II test result.
SAE J1321-2020 history
2020SAE J1321-2020 Fuel Consumption Test Procedure - Type II
2012SAE J1321-2012 Fuel Consumption Test Procedure - Type II (Includes Access to Additional Content)
1986SAE J1321-1986 Joint TMC/SAE Fuel Consumption Test Procedure Type II
1986SAE J1321-1981 Joint TMC/SAE Fuel Consumption Test Procedure - Type II, Recommended Practice