Regulatory Announcement

EPA Proposes Tier 3 Tailpipe and 

Evaporative Emission and Vehicle 

Fuel Standards 

The U.S. Environmental Protection Agency (EPA) is issuing a 

proposed rule designed to reduce air pollution from passenger 

cars and trucks. Starting in 2017, Tier 3 would set new vehicle emissions standards and lower the sulfur content of gasoline, considering 

the vehicle and its fuel as an integrated system. The proposed vehicle 

standards would reduce both tailpipe and evaporative emissions from 

passenger cars, light-duty trucks, medium-duty passenger vehicles, 

and some heavy-duty vehicles. The proposed gasoline sulfur standard 

would make emission control systems more effective for both existing 

and new vehicles, and would enable more stringent vehicle emissions 

standards since removing sulfur allows the vehicle’s catalyst to work 

more efficiently. The proposed Tier 3 standards are closely coordinated with California’s LEV III standards as well as with EPA’s and 

California’s programs for greenhouse gas (GHG) emissions from lightduty vehicles. EPA is proposing the Tier 3 standards to address public 

health issues that exist currently and are projected to continue in the 

future as requested in a May 21, 2010 Presidential memorandum. 

The Tier 3 program continues the successful transition that began 

with EPA’s Tier 2 program, finalized in 2000, in which EPA treated 

vehicles and fuels as a system to reduce both gasoline sulfur and vehicle 

emissions. While there were claims at the time that the program 

would cause fuel prices to increase far in excess of EPA’s estimates 

and would result in closures and fuel supply shortages, the Tier 2 

program was a success and resulted in gasoline sulfur reductions of 

up to 90 percent and enabled the use of new emission control technologies in cars and trucks with no serious negative impacts on the refining industry. EPA’s Clean Diesel Program similarly utilized a systems 

approach to reducing sulfur emissions from diesel fuels and enabling 

cleaner diesel technologies with the Highway Diesel Rule (finalized in 

2001) and the Nonroad Diesel Rule (finalized in 2004) again with no 

Office of Transportation and Air Quality 

EPA-420-F-13-018a 

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serious negative impacts. Now that the U.S. refining industry routinely produces lower sulfur fuel products, new market opportunities for international 

fuel exports have opened up. 

Proposed Tailpipe Emissions Standards 

EPA is proposing new tailpipe standards for the sum of non-methane organic gases (NMOG) 

and nitrogen oxides (NOX), presented as NMOG+NOX, and for particular matter (PM) that 

would apply to all light-duty vehicles and some heavy-duty vehicles. Compared to current 

standards, the proposed NMOG and NOX tailpipe standards for light-duty vehicles represent 

approximately an 80% reduction from today’s fleet average and a 70% reduction in per-vehicle PM standards. Proposed heavy-duty tailpipe standards represent about a 60% reduction in 

both fleet average NMOG+NOX and per-vehicle PM standards. EPA is also proposing to extend 

the regulatory useful life period during which the standards apply from 120,000 miles to 150,000 

miles. 

The proposed tailpipe standards include different phase-in schedules that vary by vehicle class, 

but generally phase in between model years 2017 and 2025. In addition to the gradual phase-in 

schedules, several other proposed provisions would further ease manufacturers’ paths to compliance with the stringent new standards. Depending on the standards and the vehicle class, these 

flexibility provisions include credits for early compliance and the ability to offset some higheremitting vehicles with extra-clean models. EPA is proposing more lead time for small businesses 

and small volume manufactures as well as a hardship provision that would allow for additional 

time to comply if a manufacturer cannot meet requirements after a good faith effort and would 

face severe economic hardship without the additional lead time. 

NMOG+NOX Standards: The proposed standards for NMOG+NOX are fleet-average standards, meaning that a manufacturer calculates the weighted average emissions of the vehicles 

it produces in each model year and compares that average to the applicable standard for that 

model year. The standards differ by vehicle class and test cycle. Key elements include: 

 NMOG+NOX Standards for Light-Duty Vehicles and Light-Duty Trucks (vehicles below 

8,500 pounds (lbs) Gross Vehicle Weight Rating (GVWR)), and Medium-Duty Passenger 

Vehicles (8,500 to 10,000 lbs GVWR) : 

•	 As measured on the Federal Test Procedure (FTP), the proposed standards 

decline from today’s fleet average of 160 milligrams per mile (mg/mi) to 30 mg/mi 

by 2025. 

•	 As measured on the Supplemental Federal Test Procedure (SFTP), the proposed 

standards decline from today’s fleet average of about 100 mg/mi to 50 mg/mi by 

2025. 

	NMOG+NOX Standards for Heavy-Duty Pick-ups and Vans; Class 2b (8,501-10,000 lbs 

GVWR) and Class 3(10,001-14,000GVWR)): 

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•	 As measured on the FTP, the proposed fleet average standards decline from a 

fleet average of 278 mg/mi to 178 mg/mi for Class 2b vehicles and 451 mg/mi to 

247 mg/mi for Class 3 vehicles by 2022. 

•	 Additional standards for emissions measured over a heavy-duty SFTP are being 

proposed for the first time and vary by vehicle class and power-to-weight ratio. 

PM Standards: The proposed PM standards are expressed on a per-vehicle basis, meaning the 

standards would apply to each vehicle separately (i.e., not as a fleet average). EPA is proposing 

PM standards that would differ by vehicle class and test cycle. Key elements include: 

	PM Standards for Light-Duty Vehicles, Light-Duty Trucks, and Medium-Duty Passenger 

Vehicles: 

•	 As measured on the FTP, the proposed standard is 3 mg/mi for all vehicles and 

for all model years, as compared to today’s standard of 10 mg/mi. 

•	 As measured on the US06, a high-speed, fast-acceleration component of the 

SFTP, the proposed standard is 10 mg/mi for lighter vehicles and 20 mg/mi for 

heavier vehicles. 

	PM Standards for Heavy-Duty Pick-ups and Vans; Class 2b and 3: 

•	 As measured on the FTP, the proposed PM standards are 8 mg/mi for Class 2b 

vehicles and 10 mg/mi for Class 3 vehicles. 

•	 EPA is also proposing PM standards for emissions measured over the SFTP with 

standards levels and duty cycles varying by vehicle class and power-to-weight 

ratio. 

Proposed Evaporative Emission Standards 

EPA is proposing more stringent standards designed to eliminate fuel vapor-related evaporative 

emissions and improve durability. The proposed evaporative emissions program represents about 

a 50 percent reduction from current standards and applies to all light-duty and onroad gasolinepowered heavy-duty vehicles. As with the tailpipe standards, the evaporative emissions standards includes phase-in flexibilities, credit and allowance programs, and more lead time for small 

businesses and small volume manufactures as well as a hardship provision. EPA is also proposing 

to extend the regulatory useful life period during which the standards apply from 120,000 miles 

to 150,000 miles. Key elements of the program include: 

	Evaporative Emissions Standards: Proposed standards over 2-day and 3-day evaporative 

emission tests vary by vehicle categories and range from 0.300 g/test to 0.500 for lightduty vehicles and medium duty passenger vehicles, with 0.600 g/test for onroad gasolinepowered heavy-duty vehicles. 

	Bleed Test Requirements: EPA is proposing a new testing requirement referred to as the 

bleed emission test. The bleed emissions test standard for light-duty and medium-duty 

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Regulatory Announcement

 

 

 

 

 

 

passenger vehicles is 0.020 g/test without averaging. The standard for onroad gasolinepowered heavy-duty vehicles is 0.030 g/test without averaging. 

	Leak Test and Emission Standard: EPA is proposing to add a new emission standard and 

test procedure that would require that the cumulative equivalent diameter of any orifices 

or “leaks” not exceed 0.02 inches anywhere in the fuel/evaporative system for light-duty 

vehicles, medium-duty passenger vehicles, and some gasoline-powered heavy-duty 

vehicles. 

	Onboard Diagnostic System (OBD) Requirements: EPA is proposing to adopt and 

incorporate by reference the California Air Resources Board’s (CARB) current OBD 

regulations, effective for MY 2017, that would cover all vehicles except those in the 

heavier fraction of the heavy-duty vehicle class. 

Proposed Fuel Standards 

EPA is proposing gasoline sulfur reductions that are critical to enabling manufacturers to comply 

across the fleet with the stringent proposed vehicle standards. The proposed gasoline sulfur 

standards would also achieve significant immediate benefits by reducing emissions from existing vehicles. EPA is proposing that federal gasoline contain no more than 10 parts per million 

(ppm) of sulfur on an annual average basis by January 1, 2017. In addition, EPA is proposing to 

either maintain the current 80-ppm refinery gate and 95-ppm downstream caps or lower them to 

50 and 65 ppm, respectively. The proposed Tier 3 gasoline sulfur standards are similar to levels 

already being achieved in California, Europe, Japan, South Korea, and several other countries. 

For the gasoline sulfur standards, EPA is proposing an averaging, banking, and trading (ABT) 

program that would allow refiners and importers to spread out their investments through an early 

credit program and rely on ongoing nationwide averaging to meet the 10-ppm sulfur standard. 

EPA is also proposing a three-year delay for small refiners and small volume refineries processing 

75,000 barrels of crude oil per day or less. 

Proposed Changes to Emissions Test Fuel 

EPA is proposing to update the federal emissions test fuel to better match today’s in-use gasoline and also to be forward-looking with respect to future ethanol and sulfur content. The new 

test fuel specifications would apply to new vehicle certification, assembly line, and in-use testing. EPA is proposing to transition to the new test fuel during the first few years that the Tier 

3 tailpipe and evaporative standards are phasing in. Key changes include moving to a test fuel 

containing 15 percent ethanol by volume (seeking comment on 10 percent ethanol by volume), 

lowering octane, and lowering the existing sulfur specification to be consistent with proposed 

Tier 3 requirements. EPA is also proposing test fuel specifications for E85 for the first time. 

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Regulatory Announcement

Public Participation Opportunities 

You should consult the Federal Register notice for this proposal for more information about how 

to submit comments, when the comment period will close, and about where and when public 

hearings will be held. A copy of the Federal Register notice can be found on our website listed 

below. 

EPA welcomes your comments on this proposed rule. Further information on the public comment period may be found on EPA’s website (see For More Information below). All comments 

should be identified by Docket ID No. EPA-HQ-OAR-2011-0135 and submitted by one of the 

following methods: 

Internet: www.regulations.gov 


E-mail: A-and-R-Docket@epa.gov 


Mail: 


Environmental Protection Agency 

Air and Radiation Docket and Information Center (6102T) 

1200 Pennsylvania Avenue NW 

Washington, DC 20460 

Hand Delivery: 


EPA West building 


EPA Docket Center (Room 3340) 


1301 Constitution Avenue NW 


Washington, DC 


For More Information 

You can access the rule and related documents on EPA’s Office of Transportation and Air Quality (OTAQ) Web site at: 

www.epa.gov/otaq/tier3.htm 

For more information on this rule, please contact the U.S. Environmental Protection Agency, 

Office of Transportation and Air Quality at: 

E-mail: otaq@epa.gov 

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