Regulatory Announcement

Proposed Rule for High Occupancy 

Vehicle (HOV) Facility Exemptions for 

Low Emission and Energy-Efficient 

Vehicles 

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

Proposed Rulemaking (NPRM) to implement elements of the 2005 Transportation Act (SAFETEA-LU) to provide exemptions for vehicles certified as low 

emission and energy-efficient for use in high occupancy vehicle (HOV) lanes. 

Background 

In general, vehicles using state HOV facilities must have two or more occupants. 

However, Section 1121 of The Safe, Accountable, Flexible, Efficient Transportation 

Equity Act: A Legacy for Users Act (SAFETEA-LU), which was signed into law 

on August 10, 2005, allows an exemption from the HOV occupancy requirement 

for vehicles certified as “low emission and energy-efficient.” It requires EPA to issue 

regulations for certifying vehicles as “low emission and energy-efficient.” These 

provisions are codified at 23 United States Code (U.S.C.) 166. 

Thus, this rulemaking specifically proposes the requirements for “low emission and 

energy-efficient,” including procedures for making fuel economy comparisons and 

the requirements for labeling these vehicles. As the Department of Transportation 

(DOT) is responsible for the planning and implementation of HOV programs, any 

changes to HOV programs as a result of this proposal would also be implemented by 

DOT and enforced by the individual states that choose to adopt these requirements. 

The provision allowing the HOV exemption is currently set to expire September 30, 

2009. 

Low Emission and Energy Efficient Vehicle Specifications 

•	 This proposal applies to light-duty vehicles under 8,500 pounds gross vehicle 

weight rating (GVWR). 

•	 Vehicles would be required to meet the specifications for both low emission 

and energy-efficient to be eligible for an exemption from HOV occupancy 

Office of Transportation and Air Quality 

EPA420-F-07-042 

May 2007 
Regulatory Announcement

requirements. Some hybrid vehicles will be ineligible for the exemption because they 

cannot satisfy this combined requirement. 

•	 To be considered low emission, a vehicle would have to be certified to either the federal 

Tier 2 bin 5 (or cleaner) or California LEV II emission standards. 

•	 To be considered energy efficient, a vehicle would have to be: 

o	 A dedicated alternative fuel vehicle, or 

o	 A hybrid vehicle achieving 50 percent or better in-city fuel economy or 25 

percent or better in combined city/highway fuel economy compared to a similar 

gasoline fueled vehicle. 

Fuel Economy Comparison Methodology 

The vehicle fuel economy comparison is proposed to be based on a hybrid-to-gasoline vehicle 

comparison. Using this methodology, we are proposing to compare hybrid-electric vehicles 

to their gasoline counterparts (i.e. those of the same or similar make and model type such as 

comparing the Ford Escape Hybrid to the Ford Escape gasoline model) to determine the percent 

difference in fuel economy between the hybrid and the gasoline model. This method only 

compares hybrid vehicles to gasoline vehicles. Gasoline, diesel, and flexible-fuel vehicles would 

be ineligible for HOV exemption under this proposal. For hybrid vehicles that do not have a 

similar gasoline counterpart, such as the Toyota Prius, EPA is proposing that the comparison 

be based on gasoline vehicles within the same comparable class as used in EPA’s annual Fuel 

Economy Guide, which is jointly published by EPA and DOE. The median unadjusted fuel 

economy of all the gasoline vehicles in that class would be determined, and then compared 

against the hybrid’s fuel economy. 

Labeling Requirements 

All vehicles certified as low emission and energy-efficient must be appropriately labeled for use 

in HOV facilities. States are responsible for labeling the vehicles. Existing labels, such as decals 

or license plates, are acceptable for continued use. 

Costs and Benefits 

There are no foreseen adverse economic or air quality impacts associated with this proposal. 

This proposal is expected to further the intent of Congress to provide non-financial incentives 

to increase the purchase of hybrids and other fuel efficient vehicles. 

High Occupancy Vehicle Facility Exemptions 
Regulatory Announcement

Public Participation Opportunities 

We welcome your comments on this proposed rule. Comments will be accepted for 30 days 

beginning when this proposal is published in the Federal Register. All comments should be 

identified by Docket ID No. EPA-HQ-OAR-2005-0173 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/ld-hwy.htm#hov 

For further information, please contact Holly Pugliese at: 

U.S. Environmental Protection Agency


Office of Transportation and Air Quality


2000 Traverwood Drive


Ann Arbor, MI 48105


Phone: 734-214-4288


E-mail: pugliese.holly@epa.gov 

High Occupancy Vehicle Facility Exemptions