Maryland Clean Cars Program


Adopted on November 19, 2007, The Maryland Clean Cars Program adopts California’s stricter vehicle emission standards. These standards, known as California Low Emission Vehicle Standards II (Cal LEV II), became effective in Maryland for model year 2011 vehicles, significantly reducing a number of emissions including volatile organic compounds (VOCs) and nitrogen oxides (NOx). The VOC reduction achieved from this program was expected to be 3.4 tons/days greater than the existing Federal standards and the NOx reduction was expected to be 2.9 tons/day greater than the existing Federal Tier 2 standards that were in place at the time of its adoption. VOCs and NOx emissions contribute to Maryland’s ozone problems.

The Clean Cars Program represented the first program that directly regulates carbon dioxide (CO) emissions. Transportation is the fastest-growing source of CO in the U.S. and CO2 is the most prevalent GHG. In Maryland, approximately one third of CO2 emissions are emitted from cars. In addition to regulating GHG from passenger vehicles, the Clean Cars Program includes a Zero Emissions Vehicle (ZEV) mandate that car manufacturers must meet. These vehicles produce zero or near zero tailpipe emissions and will further help reduce pollutants from the transportation sector and reduce dependence on foreign oil.

Since initially adopting the Clean Cars Program, California has developed stricter tailpipe and GHG standards. These standards, known as Cal LEV III, were also adopted by Maryland in 2012. The LEV III Program takes effect in model years 2015-2025 and sets all new emissions standards for criteria pollutants as well as GHGs. By 2025, vehicles will emit 75% less smog-forming pollutants and 34% less GHG emissions under Cal LEV III. The LEV III Program also strengthens the ZEV mandate, increasing the requirements for ZEVs beginning in 2018. ZEVs include electric vehicles and plug-in electric hybrids. For more information on ZEVs and what vehicles are available in Maryland please visit our ZEV Page​.

Federal Programs

In August 2012, EPA and NHTSA finalized a second round of fuel economy standards that were designed to mirror California’s LEV III GHG standards. The fuel economy standards are set to increase the industry’s fleet average to an equivalent of about 54.5 MPG by 2025, if achieved solely through fuel economy improvements. This program was broadly supported throughout the industry as it aligns the Federal program with California’s and eases compliance. 

In April, 2014 EPA finalized Tier 3 emission standards for light-duty vehicles. These tighter emission standards will affect all new vehicles sold beginning with the 2017 model year. The Tier 3 program reduces the fleet average emissions manufacturers must meet while also reducing the sulfur content of gasoline. The reduced sulfur content will allow for more stringent vehicle emission standards and will make emission control systems more effective. Reducing the sulfur content will also help older cars (Pre Tier 3 standards) reduce their emissions by allowing their emission control devices to run more effectively. The Tier 3 standards will closely align with California’s LEV III standards providing emission benefits to the entire nation as well as helping to improve Maryland’s air quality even more. 


The Cal Lev Program provides Maryland residents many other benefits as well. Model year 2011 and newer vehicles purchased in Maryland benefit from California’s longer emission’s warranty coverage and more comprehensive, high-cost emissions-related parts warranty. Residents also have the opportunity to purchase some of the newest advanced technology vehicles on the market, such as electric vehicles and plug-in electric hybrids.  More information on the extended warranty coverage, the available advanced technology vehicles, as well as Maryland’s Clean Car Program and Federal clean air programs is provided below.

For more information on Maryland's Clean Car Program and Federal clean air programs, please refer to the following resources: