State and Local Policy Database

Tailpipe Emission Standards

In 2004, the California Air Resources Board (CARB) adopted a rule requiring automakers to begin in the 2009 model year (MY) to phase in lower-emitting cars and trucks that will collectively emit 22% fewer greenhouse gases than 2002 vehicles in MY 2012 and 30% fewer in MY 2016. A suite of other states opted to sign on to California's more stringent standards. In 2012, CARB adopted new GHG standards for model years 2017 to 2025. Federal standards were subsequently finalized, bringing nationwide standards in line with California standards. However, California has, in addition, and updated zero-emission vehicle program that requires increasing production of plug-in and fuel-cell vehicles from 2018 to 2025. The GHG reductions are expected to be achieved largely, though not entirely, through improved vehicle efficiency, so these standards are in effect energy efficiency policies. Several technologies stand out as providing significant, cost-effective reductions in emissions. Among others, these include the optimization of valve operation, turbocharging, improved multi-speed transmissions, and improved air conditioning systems.

No policy in place or proposed.

Last Reviewed: May 2020

No policy in place or proposed.

Last Reviewed: July 2020

Arizona has no policy in place or proposed.

Last Reviewed: July 2019

No policy in place or proposed.

Last Reviewed: July 2019

Light-duty vehicles: The 2002 passage of Assembly Bill 1493 (Pavley) in California was the first time that a law in the U.S. addressed the issue of greenhouse gas (GHG) emissions from cars and light trucks. In 2004, California adopted a new set of vehicle emission standards to implement the Pavley law. The regulations required automakers to produce vehicles that, on average, reduce GHG by about 30% from 2002 levels by 2016. Increased efficiency with improved vehicle technology is the primary method for obtaining these reductions. Several other states have adopted California’s emissions program. With the adoption of more stringent federal standards in April 2010, for model years 2012-2016, California’s vehicle emission standards harmonized with the federal greenhouse gas and fuel economy programs.

In 2012, the California Air Resources Board (CARB) adopted new light duty vehicle GHG standards for model years 2017 to 2025, calling for a fleet-wide average increase in stringency of between 4-5% per year over those years. In 2012, California also updated the zero-emission vehicle (ZEV) program that requires increasing production of plug-in hybrid, battery electric, and fuel-cell electric vehicles from 2018 to 2025.

In 2016, CARB jointly published a draft Technical Assessment Report with the U.S. EPA and National Highway Traffic Safety Administration, conveying an updated cost and technology feasibility for the current standards. In January 2017, the U.S. EPA and CARB released reports finalizing their reviews, and concluded the current standards remain feasible. In April 2018, the U.S. EPA issued a revised Final Determination announcing their plans to re-open the national vehicle standards and California, along with 16 other states, filed a lawsuit opposing that action.

In November 2019, Attorney General Becerra filed a lawsuit against U.S. EPA for attacking California’s advanced clean car standards.

Heavy-duty vehicles: In August 1998, CARB identified particulate matter (PM) exhaust from diesel-fueled engines as a toxic air contaminant. CARB adopted a Diesel Risk Reduction Plan in September 2000, which recommends a number of control measures to reduce the risks associated with diesel particulate matter and achieve a goal of 75 percent PM reduction by 2010 and 85 percent by 2020.

In 2000, CARB adopted the Fleet Rule for Transit Agencies to reduce diesel PM and oxides of nitrogen emissions from urban buses and transit fleet vehicles.

In 2004, CARB adopted the Solid Waste Collection Rule to reduce emissions from solid waste collection vehicles.

In 2005, CARB approved the Fleet Rule for Public Agencies to reduce diesel PM emissions from fleets operated by public agencies and utilities.

In 2007, CARB approved the Drayage Regulation to reduce emissions from drayage trucks transporting cargo to and from California’s ports and intermodal rail yards.

In 2008, California adopted new GHG regulations to reduce emissions through the fuel efficiency improvement of tractor-trailers. Between 2010 and 2020, tractor-trailers became subject to stringent fuel economy regulations. Also in 2008, California adopted the In-Use Off-road Diesel-fueled Regulation to reduce emissions of diesel PM, oxides of nitrogen, other criteria pollutants, and greenhouse gases from off-road diesel-fueled vehicles.

In 2009, California adopted the Truck and Bus Regulation to reduce emissions of diesel PM, oxides of nitrogen, other criteria pollutants, and GHG from privately and federally owned on-road heavy-duty diesel-fueled vehicles.

In 2013, CARB adopted California Phase 1 GHG regulations that were identical to the federal Phase 1 regulations. This provided California the authority to certify new California certified engines and vehicles to the Phase 1 standards, as well as enforce those standards. Although the Phase 1 GHG standards will reduce emissions below the baseline of what they would be without any standards in place, they are not enough to offset the projected growth in heavy-duty truck vehicle miles traveled (VMT). From around 2023 forward, without standards stricter than Phase 1, GHG emissions from medium- and heavy-duty trucks would increase each year. California will need a second phase of GHG standards, the Phase 2 GHG standards, in order to offset that projected VMT growth and keep heavy-duty truck CO2 emissions declining.

In 2018, CARB adopted the Innovative Clean Transit Regulation, requiring all public transit agencies to gradually transition to a 100% zero-emission bus fleet and encouraging them to provide innovative “first and last-mile connectivity” and improved mobility for transit riders, recognizing that people are more inclined to take transit if it meshes well with the travel modes they will use for the non-transit portion of their journey.

In 2019, Senate Bill (SB) 210 directed CARB to develop a Heavy-Duty Inspection and Maintenance Program. Engine and vehicle standards for new heavy-duty vehicles have considerably reduced emissions from the heavy-duty sector. However, when emissions control systems are not operating correctly, in-use NOx and PM emissions can significantly increase. CARB’s existing programs, the Heavy-Duty Vehicle Inspection Program and the Periodic Smoke Inspection Program, ensure vehicle emissions control systems are properly operating during periodic testing. However, these programs do not adequately control NOx emissions continuously for the life of the vehicle. CARB is now exploring the development of a more comprehensive Heavy-Duty Inspection and Maintenance Program, to maintain all vehicle emissions control systems throughout the vehicles’ operating lives.

In 2020, the California Phase 2 trailer standards takes effect for all trailer manufacturers. The standards intend to make trailers more efficient and lower the greenhouse gas emissions associated with their use. Beginning January 1, 2020, trailer manufacturers must certify to California standards and receive an Executive Order from CARB to legally sell trailers in California. Also in 2020, CARB proposed the Zero-Emission Regulation, which would require private and public airport shuttle fleet owners to transition their fleet to zero-emission shuttles.

In addition, CARB developed the Advanced Clean Truck proposal to reduce GHG emissions by accelerating the first wave of zero-emission trucks and fostering a self-sustaining market. CARB is in the process of developing proposals for a number of new measures that will further advance the commercialization of zero- and near zero‑emission technologies. The Zero‑Emission Powertrain Certification will support current and future advanced‑technology measures applicable to medium‑duty vehicles, heavy‑duty vehicles, and off‑road equipment. This will ensure that once-deployed, zero‑emission technologies are able to meet the reliability and performance expectations for California fleets.

Last Reviewed: July 2020

On November 16, 2018, Colorado adopted a version of California’s low emission vehicle (LEV) standards for new light-duty and medium-duty motor vehicles sold in Colorado to take effect in the 2022 model year. The standards commit Colorado to increasingly stringent fuel efficiency standards through model year 2025.

In August 2019, the State of Colorado adopted a zero emission vehicle (ZEV) standard that will impose gradually increasing sales quotas on vehicle manufacturers, thus increasing the percentage of zero emission vehicles in Colorado. The rule allows for early action credit starting with model year 2021. Colorado's Air Quality Control Commission approved the proposed measure 8-1. More information here: https://www.colorado.gov/pacific/cdphe/zero-emission-vehicle-mandate-proposal.

Last Reviewed: May 2020

Connecticut adopted California’s Low-Emission Vehicle Program in 2005, committing to reducing criteria and greenhouse gas emissions for new vehicles through 2025. The state has also adopted California’s Zero Emission Vehicle (ZEV) program, which requires increasing production of plug-in hybrid, battery electric, and fuel-cell vehicles from 2018 to 2025 with the goal of commercializing advanced vehicle technologies that will reduce emissions and improve energy diversification in the transportation sector.

Last Reviewed: July 2019

Delaware adopted California's clean car program in December 2010.

Last Reviewed: July 2020

The District adopted the Clean Cars Act of 2008, which adopts the California emission standards and compliance requirements for vehicles of model year 2012 and thereafter. The California standards will require all cars and light trucks sold to average more than 50 miles per gallon by 2025. On May 2, 2018, Mayor Muriel Bowser issued Executive Order 2018-044, which charged the Department of Energy and Environment with implementing and enforcing the Clean Cars Act of 2008.

Last Reviewed: July 2019

No policy in place or proposed.

Last Reviewed: June 2020

No policy in place or proposed.

Last Reviewed: July 2019

No policy in place or proposed.

Last Reviewed: July 2019

While not a state-wide tailpipe emission standard, Idaho’s largest metropolitan area, the Treasure Valley (which includes Ada and Canyon counties), does require tailpipe emissions testing programs. Idaho’s Department of Environmental Quality holds certain cut-points to test against for the two counties.

Last Reviewed: June 2020

No policy in place or proposed.

Last Reviewed: July 2019

No policy in place or proposed.

Last Reviewed: July 2019

No policy in place or proposed.

Last Reviewed: July 2019

No policy in place or proposed.

Last Reviewed: July 2019

No policy in place or proposed.

Last Reviewed: July 2019

No policy in place or proposed.

Last Reviewed: July 2019

Maine adopted California’s Low-Emission Vehicle Program in 2005, committing to a 30% reduction in average new vehicle greenhouse gas emissions from 2002 levels by 2016. The state has also adopted California's Zero-Emission Vehicle (ZEV) program, which requires increasing production of plug-in hybrid, battery electric, and fuel-cell vehicles from 2018 to 2025. 

Last Reviewed: June 2020

Maryland adopted California's Zero-Emission Vehicle (ZEV) program in 2007.  California then created stricter tailpipe and GHG standards, known as Cal LEV III, which Maryland also adopted in 2012. The LEV III Program impacts model years 2015-2025 and sets new emissions standards for criteria pollutants and GHGs. The LEV III Program also strengthens the mandates for ZEVs beginning in 2018 (Source).

Last Reviewed: June 2020

Massachusetts adopted California’s Low-Emission Vehicle Program in 2006, committing to a 30% reduction in average new vehicle greenhouse gas emissions from 2002 levels by 2016. The state has also adopted California's Zero-Emission Vehicle (ZEV) program, which requires increasing production of plug-in hybrid, battery electric, and fuel-cell vehicles from 2018 to 2025. 

Last Reviewed: June 2020

No policy in place or proposed. 

Last Reviewed: May 2020

The Minnesota Pollution Control Agency is pursuing rulemaking to adopt the CA low-emission and zero-emission vehicle standards.

Last Reviewed: July 2020

No policy in place or proposed.

Last Reviewed: July 2019

The Gateway Vehicle Inspection Program is part of Missouri’s continuing effort to improve air quality in the St. Louis region. The program began in 2007 and requires an emissions inspection in the St. Louis region. The program is regulated by the State Highway Patrol and Missouri Department of Natural Resources. More information can be found online at: http://dnr.mo.gov/gatewayvip/v-owner/index.html.

Last Reviewed: May 2020

No policy in place or proposed.

Last Reviewed: June 2020

No policy in place or proposed.

Last Reviewed: June 2020

In June 2020, Governor Sisolak announced Nevada would begin a low-emission (LEV) and zero-emission vehicle (ZEV) rulemaking process.

Last Reviewed: May 2020

In the 2020 NH Legislative session House Bill 1444, requiring the adoption of innovative vehicle emissions standards pursuant to section 177 of the federal Clean Air Act, was introduced and passed by the House of Representatives.  Due to COVID-19 the Senate has not convened and it is unlikely to be acted upon in the current session.

Last Reviewed: May 2020

In January 2006, New Jersey adopted rules to implement the California Low Emission Vehicle (LEV) program beginning in 2009. These rules implement the Air Pollution Control Act provisions at N.J.S.A. 26:2C-8.15, which require the Department to promulgate rules to implement the California LEV program in New Jersey. The New Jersey program contains three components: vehicle emission standards, fleet wide emission requirements, and a Zero Emission Vehicle (ZEV) sales requirement. The rules will require automakers to reduce fleet-wide greenhouse gas emissions from the vehicles they sell in New Jersey 30% by 2016. The state has also adopted California's Zero-Emission Vehicle (ZEV) program, which requires increasing production of plug-in hybrid, battery electric, and fuel-cell vehicles from 2018 to 2025.

On April 3rd, 2018, Governor Murphy reaffirmed New Jersey’s support for federal fuel emissions standards and signed a multi-state agreement on clean vehicles. Furthermore, in December 2018, New Jersey committed to working with Northeast and Mid-Atlantic states to consider the development of a new regional low-carbon transportation policy proposal that will reduce greenhouse gas emissions from the transportation sector. The Transportation and Climate Initiative (TCI) recognizes that a regional low-carbon transportation policy will spur policies and programs to reduce carbon emissions, improve air quality, help communities become more resilient to extreme weather, spur economic growth, and address the disproportionate burdens of climate change on environmental justice communities. Most recently, on July 14, 2020, New Jersey joined 14 other states and the District of Columbia committed to work collaboratively to advance and accelerate the market for electric medium- and heavy-duty vehicles, including large pickup trucks and vans, delivery trucks, box trucks, school and transit buses, and long-haul delivery trucks (big-rigs). The goal is to ensure that 100 percent of all new medium- and heavy-duty vehicle sales be zero emission vehicles by 2050 with an interim target of 30 percent zero-emission vehicle sales by 2030.

Last Reviewed: July 2020

The state is currently drafting rules that would adopt California’s ZEV program, which requires increasing production of plug-in hybrid, battery electric, and fuel cell vehicles from 2018 to 2025. Plans to further incentive EVs and EV charging infrastructure are pending.

Last Reviewed: July 2020

New York adopted California's Low-Emission Vehicle Program in 2005, committing to a 30% reduction in average new vehicle greenhouse gases from 2002 levels by 2016. The state has also adopted California’s Zero-Emission Vehicle (ZEV) program, which requires increasing sales of plug-in hybrid, battery electric, and fuel-cell vehicles from 2018 to 2025.

Last Reviewed: November 2020

No policy in place or proposed.

Last Reviewed: July 2020

No policy in place or proposed.

Last Updated: July 2017

No policy in place or proposed.

Last Reviewed: July 2019

No policy in place or proposed.

Last Reviewed: May 2020

Oregon adopted California’s Low-Emission Vehicle Program in 2006, committing to a 30% reduction in average new vehicle greenhouse gas emissions from 2002 levels by 2016. The state has also adopted California's Zero-Emission Vehicle (ZEV) program, which requires increasing production of plug-in hybrid, battery electric, and fuel-cell vehicles from 2018 to 2025. 

Last Reviewed: July 2019

Pennsylvania adopted California’s Low Emission Vehicle Program in 1998 for light-duty vehicles as a backstop measure for the National Low Emission Vehicle Program. The California standards went into effect in 2006 in Pennsylvania, effective for model years 2008 and later, which contributed to a 30% reduction in average new vehicle greenhouse gas emissions from 2002 levels by 2016. Federal greenhouse gas standards for model years 2012 through 2025 were harmonized with California's standards.  Newer California standards along with federal standards originally applied to model year vehicles 2017 through 2025, however these were rolled back by the federal Safer Affordable Fuel Efficient (SAFE) Vehicles Act in 2020.

Last Reviewed: June 2020

Rhode Island adopted California’s Low-Emission Vehicle Program in 2005, committing to a 30% reduction in average new vehicle greenhouse gas emissions from 2002 levels by 2016. The state has also adopted California's Zero-Emission Vehicle (ZEV) program, which requires increasing production of plug-in hybrid, battery electric, and fuel-cell vehicles from 2018 to 2025. 

Last Reviewed: June 2020

No policy in place or proposed.

Last Reviewed: July 2019

No policy in place or proposed.

Last Reviewed: July 2019

No policy in place or proposed. 

Last Reviewed: July 2019

No policy in place or proposed.

Last Reviewed: May 2020

No policy in place or proposed.

Last Reviewed: June 2020

Vermont adopted California’s Low-Emission Vehicle Program in 2005, committing to a 30% reduction in average new vehicle greenhouse gas emissions from 2002 levels by 2016. The state has also adopted California's Zero-Emission Vehicle (ZEV) program, which requires increasing production of plug-in hybrid, battery electric, and fuel-cell vehicles from 2018 to 2025. 

Last Reviewed: June 2020

No policy in place. In the Governor's 2018 Virginia Energy Plan it was recommended that the Commonwealth should adopt the Advanced Clean Cars (ACC) program. The ACC program includes both low-emission vehicle (LEV) standards as well as the Zero Emission Vehicles (ZEV) program. Adopting the LEV standards is especially important in light of recent federal action to roll back fuel efficiency standards, and a ZEV program would increase access to a wide range of EV models. Consumer access is linked to higher adoption rates and, as of 2015, 65% of nationwide EV sales had occurred in the nine states with a ZEV program.

Last Reviewed: June 2020

 

Washington adopted California’s Low-Emission Vehicle Program in 2005, committing to a 30% reduction in average new vehicle greenhouse gas emissions from 2002 levels by 2016.

In March 2020, the state enacted SB 5811, requiring the state’s Department of Ecology to begin a rulemaking for a Zero Emission Vehicles (ZEV) program.

Last Reviewed: May 2020

No policy in place or proposed.

Last Reviewed: July 2019

No policy in place or proposed.

Last Reviewed: July 2019

No policy in place or proposed.

Last Reviewed: July 2019