SM Interim Test Method for Verifying 

Fuel-Saving Components for SmartWay: 

Modifications to SAE J1321

 

U.S. Environmental Protection 

Agency Certified SmartWay tractors and trailers are a new generation of long-haul rigs equipped 

with cleaner, fuel-saving 

features. SmartWay tractors and 

trailers can achieve fuel savings 

of 10 to 20 percent (saving carriers between 1,700 and 3,300 

gallons of diesel fuel annually), 

lower greenhouse-gas emissions, 

and significantly reduce oxides of 

nitrogen, particulate matter, and 

other air pollutants. 

This is an EPA document describing how the Joint TMC/SAE Fuel 

Consumption Test Procedure – 

Type II (SAE J1321 Surface Vehicle 

Recommended Practice (October, 

1986) can be adapted as an interim 

test method to quantify the fuel 

consumption impact of fuel-saving 

equipment for the purpose of determining eligibility for inclusion in 

SmartWay.

Description of Interim Test Method

The Joint TMC/SAE Fuel Consumption Test Procedure – Type II (SAE 

J1321 Surface Vehicle Recommended Practice (October, 1986) is modified 

by adding the following provisions:

1. Test must be conducted on a test track, not a roadway. 

2. Test track length > 1.5 miles (5 miles recommended).

3. Track must be circular, figure eight, or oval in shape.

4. Track surface must be completely dry and well-maintained; surface 

typical of highway surfaces (asphalt or cement).

5. Grade change on test track not greater than 2 degrees. 

6. Altitude of test facility not greater than 4,000 feet above sea level. 

7. No precipitation on the test track for duration of test. 

8. Temperatures at the test track must be 68 - 86 F for duration of test.

9. Wind speed at the test track cannot exceed 12 mph for duration of test.

10. Wind gusts at the test track cannot exceed 15 mph for duration of test.

11. Top speed of test drive cycle not to exceed 65 mph.

12. Test trailer configuration must be a typical dry box semi-trailer, 53’ long, 

102” wide, and 13’ 6” high.

13. Trailers must be the same model and similar age, mileage and 

condition.

14. Each trailer must have the same test payload. The combined weight of 

the trailer and payload must be approximately 46,000 pounds, +/- 500 

pounds. 

15. Test payload must be loaded over axle to be consistent with federal 

bridge laws. Payload must be secured so it does not shift during the 

test.

16. Tires must be inflated to manufacturer-recommended maximum cold 

inflation pressure prior to start of test.

17. Tires must be as similar as possible in size and condition, and have 

accumulated at least 500 miles wear-in prior to start of test.

18. The tractor-trailer gap must as similar as possible on both pairs of 

trucks, as measured from the back of the tractor to the front of the 

trailer.

19. If testing a candidate tractor against a current SmartWay tractor 

model for the purpose of demonstrating SmartWay eligibility, the two 

tractors must have substantially similar drive train and power train 

configuration, including gear ratio, engine horsepower and size, 

transmission type, lubricant type, rear axle ratio, accumulated mileage, 

emissions aftertreatment system, etc.

20. If testing trailer modifications or trailer aerodynamic equipment, 

test tractors must be equipped with features typical of line haul 

combination trucks – e.g., high roof fairing, side cab extender fairings, 

and aerodynamic profile.

21. EPA must review and approve the test plan and the vehicle 

configurations prior to testing. 

Summay of SmartWay 

Tractor & Trailer 

Program

SmartWay Transport | EPA-420-F-09-046 | www.epa.gov/smartway | 734-214-4767 | smartway_transport@epa.gov
22. EPA reserves the right to review all test data and 

to reject any test it determines was not conducted 

in accordance with these provisions and / or SAE 

J1321, or otherwise not credible according to good 

engineering judgment. 

General requirement: 

All provisions of SAE J1321 must be followed, in addition 

to the above EPA provisions. Trucks must be prepped 

and maintained according to SAE J1321, and results 

must be within SAE test minimum acceptable ratios 

to be a valid test. All measurement devices must be 

NIST-traceable. The fuel must meet all applicable ASTM 

standards for motor fuel for the intended application.

Contact EPA

Interested organizations should contact SmartWay prior 

to testing. 

To contact EPA, 

• send an e-mail to: SmartWay-tech@epa.gov

• telephone the SmartWay Transport Partnership Call 

Center at (734) 214-4767

• write to SmartWay Transport Partnership, US EPA, 

2000 Traverwood, Ann Arbor, MI 48105. 

If you have questions regarding SmatWay Certified 

Tractors and Trailers or SmartWay verified technologies, 

contact the SmartWay Technology Team at: 

SmartWay-tech@epa.gov.

SmartWay Transport | EPA-420-F-09-046 | www.epa.gov/smartway | 734-214-4767 | smartway_transport@epa.gov