Mapping Current Events

This series is designed to teach you about our legal structure in the context of current political events.  Go deeper, past news articles, with this infographic.  

This map's topic is Auto Emissions Regulation.  

See the map below and the introductory blog post here.  If you haven't already, check out the basic map explained, so you can understand why we organized the information this way.

auto emissions regulation

The Constitution

the constitution

The Constitution does not specifically reference environmental protections.  However, there are a few provisions in the Constitution that have been referenced as relevant to environmental advocacy.

In the 14th Amendment and in the 5th Amendment, citizens are guaranteed the rights to life, liberty and property (Substantive Due Process).  The government may not make policies that violate these rights.  But what rights are included in “life, liberty and property”?  Up through today, these “fundamental rights” do not include the right to a clean environment, but there is a live lawsuit arguing just that. See Juliana v. United States in the Judicial column (citizens winning an initial ruling that their argument has some potential).

The First Amendment relating to free speech is relevant to environmental advocacy.  The First Amendment includes the “Right to Petition Government” clause, which says, “Congress shall make no law . . . abridging . . . the right of the people . . . to petition Government for a redress of grievances.”  A group of environmental organizations used this clause to support their petition demanding the EPA to make rules controlling auto emissions. See Executive column, Environmental Groups’ Petition to EPA (1999).

Legislative Branch


The Clean Air Act of 1963 was the start of major federal legislation on air pollution.  It funded the study of and the cleanup of air pollution.  But the federal government did not start acting comprehensively to clean up the air until the Clean Air Act of 1970.

The Clean Air Act of 1970 established the Environmental Protection Agency, which gave the federal government more power to implement policies protecting clean air.  Congress made other amendments to the Clean Air Act in 1977 and 1990.  See here for a “plain English” explanation of the Clean Air Act.

Particular provisions in the Clean Air Act:

Regarding the regulation of auto emissions, the Clean Air Act gives a general grant of power to the Environmental Protection Agency (EPA). The EPA must regulate air pollutants from new motor vehicles. The Act sets the boundaries of the EPA’s authority to regulate. For example, the Act defines “air pollutants” and states the types that the EPA must regulate (those “which may be reasonably anticipated to endanger public health or welfare”), and it states that the agency must “from time to time” revise the regulations. In another area, the Act says that the EPA must consult with the Department of Transportation (DOT) when it issues rules on certain standards relevant to DOT authority.  Further, although the EPA is the primary authority on setting auto emissions standards, the Act says the EPA must allow California to set its own standards. See the State section below for more information on California’s special status. See the Executive column for a broader discussion of the EPA’s actions controlling auto emissions.

Regarding citizens’ rights to advocate for the environment, the Clean Air Act was the first major environmental law allowing citizens the right to sue if someone or some entity (even the EPA) violates the Act and such violation causes that citizen harm.  See Massachusetts v. EPA in the Judicial column, for an example of a suit using this provision.  See also Administrative Procedure Act below, which gives citizens another right to sue.

The Energy Policy and Conservation Act of 1975 is another federal law related to the control of auto emissions.  It was passed with the general goal of creating comprehensive federal policy related to energy (conservation and supply).  The Act requires the Department of Transportation (DOT) to make fuel economy standards on passenger cars and light trucks.  This statute is referenced in Massachusetts v. EPA (see Judicial column).  

Other relevant federal legislation:

The Administrative Procedure Act (APA) is always relevant when there is a federal agency (like the EPA) involved.  The Administrative Procedure Act limits federal agencies (executive branch) from abuse of power.  It makes sure that agencies act fairly.  For example, agencies must follow proper procedures when they make rules or decisions, and they cannot overstep the boundaries of their power.  This means the EPA is limited by the authority granted to it in the Clean Air Act.  When the EPA makes rules, it must follow certain procedures (e.g. provide notice to the public that it plans to make rules and allow the public an opportunity to comment).  When it makes decisions, it must meet certain standards of fairness.  The Administrative Procedure Act also gives citizens, companies, or other groups the right to sue if the procedures are not followed causing that citizen (or entity) harm.  This is called a “private right of action” (right to sue).  



Executive Branch

president and Executive agencies

The President

As the leader of the executive branch, the President can influence environmental policy by issuing executive guidance and making executive orders telling executive agencies how to act.  For example, in 2009 Obama set a “National Fuel Efficiency Policy” indicating that the executive agencies were on track to creating comprehensive national standards on fuel economy.  In 2016, Obama issued an executive order telling his agencies to take climate change into account when they issue rules.

The President also has power to make treaties. For example, President H.W. Bush signed the United Nations Framework Convention on Climate Change in 1992, agreeing to reduce atmospheric greenhouse gas concentrations (like carbon dioxide).  Obama also signed a United Nations climate change pact in 2016, agreeing that the U.S. would reduce carbon emissions.  Fulfilling a promise in a treaty requires the President to direct the executive agencies to take actions in furtherance of the agreement.

Executive Agencies

Although executive agencies implement the policy directives of the President, agencies primarily get their responsibilities from federal legislation.  The President cannot make agencies act outside of the boundaries set in legislation (or they all may get sued; see Administrative Procedure Act).

The following federal agencies are responsible to make regulations relating to auto emissions:

The Environmental Protection Agency (EPA) is the federal agency primarily responsible for issuing federal standards on greenhouse gas emissions (which includes auto emissions) under the Clean Air Act.  

The Department of Transportation (DOT) is responsible for making miles-per-gallon standards (ensuring new cars produced do not burn too much gas) under the Energy Policy and Conservation Act.  DOT delegated this responsibility to its own sub-agency, the National Highway Traffic Safety Administration (NHTSA).  The NHTSA established the Corporate Average Fuel Economy (CAFE) standards, which include miles-per-gallon fuel efficiency standards.  

The first set of joint rules between these two agencies came under President Obama in 2012 (listed below).  But first, here is an example of citizens’ advocacy that put pressure on the EPA to regulate auto emissions, after years of inaction by the agency.

Environmental Groups’ Petition to EPA

In 1999, a group of environmental organizations submitted a petition to the Environmental Protection Agency requesting the agency to regulate gas emissions from autos.  The Clean Air Act (see Legislative column) gives citizens the right to petition the EPA for rulemaking (see also the “Right to Petition Government” clause in the Constitutional section), and the agency must take proper consideration of the petition in making a decision on it. The EPA, after requesting public comments (receiving more than 50,000), denied the petition, saying it did not have authority to regulate greenhouse gases and that Congress already gave the Department of Transportation authority to regulate to improve fuel economy (see the Energy Policy and Conservation Act in the Legislative column).  The environmental groups sued.  See Massachusetts v. EPA in the Judicial column (rejecting the EPA’s arguments).

2012 EPA and DOT Joint Regulations

In 2012, the EPA and DOT issued updated rules on auto emissions: “2017 and Later Model Year Light-Duty Vehicle Greenhouse Gas Emissions and Corporate Average Fuel Economy Standards.”  The rules provide for a midterm review of standards, to be conducted “concurrently” by the EPA and DOT by April 2018.  In January 2017 (weeks before President Obama left office), the EPA finalized its midterm review. DOT did not sign onto the final EPA midterm review.  In March 2017, the Trump administration indicated it plans to re-do the midterm review, citing the absence of DOT as its basis.  Either environmental groups, on the one hand, and auto-makers, on the other, could potentially bring suit against the federal agencies (DOT and the EPA) depending on what happens with the rules.  See Judicial column for a discussion.

Judicial Branch

federal courts

These first two examples were chosen for their relevance to recent (early Trump administration) controversy over federal regulations on auto emissions:

Lawsuit Leading up to the 2012 EPA and DOT Joint Regulations:

In Massachusetts v. EPA (2007), 19 environmental groups sued the EPA because the groups had requested the EPA to regulate auto emissions, and the EPA refused (see the petition described in the Executive column).  The groups brought the case to federal appeals court (the District of Columbia Circuit Court of Appeals), arguing the EPA "abused its discretion" in denying their petition.  After losing in the federal appeals court, the environmental groups requested for the Supreme Court to hear the case.  The Supreme Court reversed the ruling.  The Supreme Court said that the EPA had not taken a proper reasoning process when it denied the petition of the environmental groups.    

The Court said: “Under the clear terms of the Clean Air Act, EPA can avoid taking further action only if it determines that greenhouse gases do not contribute to climate change or if it provides some reasonable explanation as to why it cannot or will not exercise its discretion to determine whether they do.” In the end, the Court reversed the EPA’s denial of the petition. The Court also ruled that even though DOT has responsibility for setting mileage standards, the EPA still has responsibility to regulate greenhouse gases, which include auto emissions.  This case paved the way for the current regulations (see the 2012 EPA and DOT Joint Regulations in the Executive column).

Potential for Suit regarding the Midterm Review of the EPA and DOT Joint Regulations:

The 2012 EPA and DOT Joint Regulations provide for a midterm review, so that the agencies could check in on the standards, by April 2018.  During the midterm review, the agencies could decide if adjustment would be necessary for upcoming model year autos.  As the Executive column notes, Obama’s EPA issued the midterm review early (in January 2017, just before Obama left office), leaving in place the existing relatively strict standards.  Trump has indicated he will re-do the midterm review.  Normally, once a rulemaking (like this midterm review) is final, an incoming president must follow strict procedures in order to repeal that rule.  However, Trump is arguing that the absence of DOT in the EPA’s midterm review makes the review invalid.  If Trump invalidates the midterm review that the EPA issued in January 2017, environmental groups will probably sue on grounds that Trump, DOT and the (new) EPA are abusing their discretion.  This case might include claims under both the Administrative Procedure Act and the Clean Air Act.  Alternatively, automobile makers (represented by groups like the Alliance of Automobile Manufacturers) might sue if the midterm review is NOT re-done.  They could claim that the agency did not have authority to issue the midterm review without DOT.  Keep a lookout for litigation on this issue.

Suit Grounding Environmental Protection in Constitutional Rights:

In Juliana v. United States, a group of 21 young people around the nation sued the federal government (in federal district court for the District of Oregon) arguing that the government’s failure to address climate change is a violation of their Constitutional rights.  The plaintiffs argue that by knowing the harmful effects of climate change, the government has a responsibility to act, and by not acting, the plaintiffs’ Constitutional rights to life, liberty and property (Substantive Due Process) are violated.  The judge heard initial arguments by the government (the Obama administration) that the plaintiffs’ claims were not valid, but the judge denied to dismiss the case.  This is a landmark ruling: the first time a federal judge agrees that the “right to a climate system capable of sustaining life” is a fundamental Constitutional right, obligating the government to protect the environment.  This early ruling does not mean the plaintiffs have won the case (it’s not a ruling “on the merits”).  It means, rather, that the plaintiffs have presented a strong enough argument that they will get a trial (to present evidence in support of these novel arguments they are making).  See here for more information about the ongoing case (including the trial schedule), a case which the Trump administration is adopting.

The States

state governments

Generally, states can make stricter standards to protect state citizens than as provided in federal law, as long as state policies do not conflict with federal law.  But in this case, both Clean Air Act and the Energy Policy and Conservation Act say specifically that states cannot make stricter standards to control auto emissions.

However, there is an exception in the Clean Air Act.  The Clean Air Act says that if a state had adopted equally- or more-stringent standards on auto emissions before March 30, 1966, that state may make more-stringent standards than the EPA.  California is the only state that satisfies this provision.  The provision requires California to get a “waiver” from the EPA, but the EPA can deny California only under certain conditions.  To deny California, the agency will have to stray from precedent because California has been issued this waiver as a matter of course in the past.  Alternatively (and more drastically), Congress can re-legislate and remove this exemption for California from the Clean Air Act.  If that happens, environmental groups surely will seek an even higher authority to sue, which would have to be on Constitutional grounds (see Juliana v. United States, Judicial column).

The California Air Resources Board sets rules on emissions of greenhouse gases (auto emissions) for the State of California.  Because the market for automobiles is dependent on California drivers, the result of California’s special status is that automakers end up complying with California’s more stringent standards for all of the autos they make for the nation.  In the current regulations (2012 EPA and DOT Joint Regulations), the California Air Resources Board and the federal agencies (the EPA and DOT) have cooperated on making standards.