The Secretary shall establish and implement a congestion mitigation and air quality improvement program in accordance with this section.

Except as provided in subsection (d), a State may obligate funds apportioned to it under section 104(b)(4) for the congestion mitigation and air quality improvement program only for a transportation project or program if the project or program is for an area in the State that is or was designated as a nonattainment area for ozone, carbon monoxide, or particulate matter under section 107(d) of the Clean Air Act (42 U.S.C. 7407(d)) and classified pursuant to section 181(a), 186(a), 188(a), or 188(b) of the Clean Air Act (42 U.S.C. 7511(a), 7512(a), 7513(a), or 7513(b)) or is or was designated as a nonattainment area under such section 107(d) after December 31, 1997, or is required to prepare, and file with the Administrator of the Environmental Protection Agency, maintenance plans under the Clean Air Act (42 U.S.C. 7401 et seq.) and—

if the Secretary, after consultation with the Administrator determines, on the basis of information published by the Environmental Protection Agency pursuant to section 108(f)(1)(A) of the Clean Air Act (other than clause (xvi)) that the project or program is likely to contribute to—

(A) (i) if the Secretary, after consultation with the Administrator determines, on the basis of information published by the Environmental Protection Agency pursuant to section 108(f)(1)(A) of the Clean Air Act (other than clause (xvi)) that the project or program is likely to contribute to— (I) the attainment of a national ambient air quality standard in the designated nonattainment area; or (II) the maintenance of a national ambient air quality standard in a maintenance area; and (ii) a high level of effectiveness in reducing air pollution, in cases of projects or programs where sufficient information is available in the database established pursuant to subsection (h) to determine the relative effectiveness of such projects or programs; or,

(B) in any case in which such information is not available, if the Secretary, after such consultation, determines that the project or program is part of a program, method, or strategy described in such section 108(f)(1)(A);

(2) if the project or program is included in a State implementation plan that has been approved pursuant to the Clean Air Act and the project will have air quality benefits;

(3) the Secretary, after consultation with the Administrator of the Environmental Protection Agency, determines that the project or program is likely to contribute to the attainment or maintenance of a national ambient air quality standard, whether through reductions in vehicle miles traveled, fuel consumption, or through other factors;

(4) to establish or operate a traffic monitoring, management, and control facility or program, including advanced truck stop electrification systems, if the Secretary, after consultation with the Administrator of the Environmental Protection Agency, determines that the facility or program is likely to contribute to the attainment or maintenance in the area of a national ambient air quality standard;

(5) if the program or project improves traffic flow, including projects to improve signalization, construct high occupancy vehicle lanes, improve intersections, add turning lanes, improve transportation systems management and operations that mitigate congestion and improve air quality, and implement intelligent transportation system strategies and such other projects that are eligible for assistance under this section on the day before the date of enactment of this paragraph, including programs or projects to improve incident and emergency response or improve mobility, such as through real-time traffic, transit, and multimodal traveler information;

(6) if the project or program involves the purchase of integrated, interoperable emergency communications equipment;

(7) if the project or program shifts traffic demand to nonpeak hours or other transportation modes, increases vehicle occupancy rates, or otherwise reduces demand for roads through such means as telecommuting, ridesharing, carsharing, alternative work hours, and pricing;

if the project or program is for—

(A) the purchase of diesel retrofits that are— (i) for motor vehicles (as defined in section 216 of the Clean Air Act (42 U.S.C. 7550)); or (ii) verified technologies (as defined in section 791 of the Energy Policy Act of 2005 (42 U.S.C. 16131)) for non-road vehicles and non-road engines (as defined in section 216 of the Clean Air Act (42 U.S.C. 7550)) that are used in construction projects or port-related freight operations that are— (I) located in nonattainment or maintenance areas for ozone, PM10, or PM2.5 (as defined under the Clean Air Act (42 U.S.C. 7401 et seq.)); and (II) funded, in whole or in part, under this title or chapter 53 of title 49; or

(B) the conduct of outreach activities that are designed to provide information and technical assistance to the owners and operators of diesel equipment and vehicles regarding the purchase and installation of diesel retrofits; or

(9) if the project or program is for the installation of vehicle-to-infrastructure communication equipment.

A State may obligate funds apportioned to the State under section 104(b)(4) for a project or program for an area that is nonattainment for ozone or carbon monoxide, or both, and for PM–10 resulting from transportation activities, without regard to any limitation of the Department of Transportation relating to the type of ambient air quality standard such project or program addresses.

(1) Projects for pm–10 nonattainment areas.— A State may obligate funds apportioned to the State under section 104(b)(4) for a project or program for an area that is nonattainment for ozone or carbon monoxide, or both, and for PM–10 resulting from transportation activities, without regard to any limitation of the Department of Transportation relating to the type of ambient air quality standard such project or program addresses.

(2) Electric vehicle and natural gas vehicle infrastructure.— A State may obligate funds apportioned under section 104(b)(4) for a project or program to establish electric vehicle charging stations or natural gas vehicle refueling stations for the use of battery powered or natural gas fueled trucks or other motor vehicles at any location in the State (giving priority to corridors designated under section 151) except that such stations may not be established or supported where commercial establishments serving motor vehicle users are prohibited by section 111 of title 23, United States Code.

(3) HOV facilities.— No funds may be provided under this section for a project which will result in the construction of new capacity available to single occupant vehicles unless the project consists of a high occupancy vehicle facility available to single occupant vehicles only at other than peak travel times.

If a State does not have, and never has had, a nonattainment area designated under the Clean Air Act (42 U.S.C. 7401 et seq.), the State may use funds apportioned to the State under section 104(b)(4) for any project in the State that—

If a State does not have, and never has had, a nonattainment area designated under the Clean Air Act (42 U.S.C. 7401 et seq.), the State may use funds apportioned to the State under section 104(b)(4) for any project in the State that—

(A) would otherwise be eligible under subsection (b) as if the project were carried out in a nonattainment or maintenance area; or

(B) is eligible under the surface transportation block grant program under section 133.

If a State has a nonattainment area or maintenance area and received funds in fiscal year 2009 under section 104(b)(2)(D), as in effect on the day before the date of enactment of the MAP–21, above the amount of funds that the State would have received based on the nonattainment and maintenance area population of the State under subparagraphs (B) and (C) of section 104(b)(2), as in effect on the day before the date of enactment of the MAP–21, the State may use for any project that would otherwise be eligible under subsection (b) if the project were carried out in a nonattainment or maintenance area or is eligible under the surface transportation block grant program under section 133 an amount of funds apportioned to such State under section 104(b)(4) that is equal to the product obtained by multiplying—

(A) In general.—If a State has a nonattainment area or maintenance area and received funds in fiscal year 2009 under section 104(b)(2)(D), as in effect on the day before the date of enactment of the MAP–21, above the amount of funds that the State would have received based on the nonattainment and maintenance area population of the State under subparagraphs (B) and (C) of section 104(b)(2), as in effect on the day before the date of enactment of the MAP–21, the State may use for any project that would otherwise be eligible under subsection (b) if the project were carried out in a nonattainment or maintenance area or is eligible under the surface transportation block grant program under section 133 an amount of funds apportioned to such State under section 104(b)(4) that is equal to the product obtained by multiplying— (i) the amount apportioned to such State under section 104(b)(4) (excluding the amount of funds reserved under subsection (k)(1)); by (ii) the ratio calculated under subparagraph (B).

(B) Ratio.—For purposes of this paragraph, the ratio shall be calculated as the proportion that— (i) the amount for fiscal year 2009 such State was permitted by section 149(c)(2), as in effect on the day before the date of enactment of the MAP–21, to obligate in any area of the State for projects eligible under section 133, as in effect on the day before the date of enactment of the MAP–21; bears to (ii) the total apportionment to such State for fiscal year 2009 under section 104(b)(2), as in effect on the day before the date of enactment of the MAP–21.

(3) Changes in designation.— If a new nonattainment area is designated or a previously designated nonattainment area is redesignated as an attainment area in a State under the Clean Air Act (42 U.S.C. 7401 et seq.), the Secretary shall modify, in a manner consistent with the approach that was in effect on the day before the date of enactment of MAP–21, the amount such State is permitted to obligate in any area of the State for projects eligible under section 133.

Programming and expenditure of funds for projects under this section shall be consistent with the requirements of sections 134 and 135 of this title.

Participation by an entity under paragraph (1) may consist of—

(1) In general.— Notwithstanding any other provision of this title and in accordance with this subsection, a metropolitan planning organization, State transportation department, or other project sponsor may enter into an agreement with any public, private, or nonprofit entity to cooperatively implement any project carried out under this section.

Participation by an entity under paragraph (1) may consist of—

(A) ownership or operation of any land, facility, vehicle, or other physical asset associated with the project;

(B) cost sharing of any project expense;

(C) carrying out of administration, construction management, project management, project operation, or any other management or operational duty associated with the project; and

(D) any other form of participation approved by the Secretary.

(3) Allocation to entities.— A State may allocate funds apportioned under section 104(b)(4) to an entity described in paragraph (1).

In the case of a project that will provide for the use of alternative fuels by privately owned vehicles or vehicle fleets, activities eligible for funding under this subsection—

(A) may include the costs of vehicle refueling infrastructure, including infrastructure that would support the development, production, and use of emerging technologies that reduce emissions of air pollutants from motor vehicles, and other capital investments associated with the project;

(B) shall include only the incremental cost of an alternative fueled vehicle, as compared to a conventionally fueled vehicle, that would otherwise be borne by a private party; and

(C) shall apply other governmental financial purchase contributions in the calculation of net incremental cost.

(5) Prohibition on federal participation with respect to required activities.— A Federal participation payment under this subsection may not be made to an entity to fund an obligation imposed under the Clean Air Act (42 U.S.C. 7401 et seq.) or any other Federal law.

In this subsection, the following definitions apply:

In this subsection, the following definitions apply:

(A) Administrator.— The term “Administrator” means the Administrator of the Environmental Protection Agency.

(B) Diesel retrofit.— The term “diesel retrofit” means a replacement, repowering, rebuilding, after treatment, or other technology, as determined by the Administrator.

The Administrator, in consultation with the Secretary, shall publish a list of diesel retrofit technologies and supporting technical information for—

(A) diesel emission reduction technologies certified or verified by the Administrator, the California Air Resources Board, or any other entity recognized by the Administrator for the same purpose;

(B) diesel emission reduction technologies identified by the Administrator as having an application and approvable test plan for verification by the Administrator or the California Air Resources Board that is submitted not later than 18 months of the date of enactment of this subsection;

(C) available information regarding the emission reduction effectiveness and cost effectiveness of technologies identified in this paragraph, taking into consideration air quality and health effects.

(3) Priority consideration.— States and metropolitan planning organizations shall give priority in areas designated as nonattainment or maintenance for PM2.5 under the Clean Air Act (42 U.S.C. 7401 et seq.) in distributing funds received for congestion mitigation and air quality projects and programs from apportionments under section 104(b)(4) to projects that are proven to reduce PM2.5, including diesel retrofits.

(4) No effect on authority or restrictions.— Nothing in this subsection modifies or otherwise affects any authority or restriction established under the Clean Air Act (42 U.S.C. 7401 et seq.) or any other law (other than provisions of this title relating to congestion mitigation and air quality).

The Secretary shall encourage States and metropolitan planning organizations to consult with State and local air quality agencies in nonattainment and maintenance areas on the estimated emission reductions from proposed congestion mitigation and air quality improvement programs and projects.

Using appropriate assessments of projects funded under the congestion mitigation and air quality program and results from other research, the Secretary shall maintain and disseminate a cumulative database describing the impacts of the projects, including specific information about each project, such as the project name, location, sponsor, cost, and, to the extent already measured by the project sponsor, cost-effectiveness, based on reductions in congestion and emissions.

Using appropriate assessments of projects funded under the congestion mitigation and air quality program and results from other research, the Secretary shall maintain and disseminate a cumulative database describing the impacts of the projects, including specific information about each project, such as the project name, location, sponsor, cost, and, to the extent already measured by the project sponsor, cost-effectiveness, based on reductions in congestion and emissions.

(A) In general.— Using appropriate assessments of projects funded under the congestion mitigation and air quality program and results from other research, the Secretary shall maintain and disseminate a cumulative database describing the impacts of the projects, including specific information about each project, such as the project name, location, sponsor, cost, and, to the extent already measured by the project sponsor, cost-effectiveness, based on reductions in congestion and emissions.

(B) Availability.— The database shall be published or otherwise made readily available by the Secretary in electronically accessible format and means, such as the Internet, for public review.

The Secretary, in consultation with the Administrator of the Environmental Protection Agency, shall evaluate projects on a periodic basis and develop a table or other similar medium that illustrates the cost-effectiveness of a range of project types eligible for funding under this section as to how the projects mitigate congestion and improve air quality.

(A) In general.— The Secretary, in consultation with the Administrator of the Environmental Protection Agency, shall evaluate projects on a periodic basis and develop a table or other similar medium that illustrates the cost-effectiveness of a range of project types eligible for funding under this section as to how the projects mitigate congestion and improve air quality.

(B) Contents.— The table described in subparagraph (A) shall show measures of cost-effectiveness, such as dollars per ton of emissions reduced, and assess those measures over a variety of timeframes to capture impacts on the planning timeframes outlined in section 134.

(C) Use of table.— States and metropolitan planning organizations shall consider the information in the table when selecting projects or developing performance plans under subsection (l).

At the discretion of a metropolitan planning organization, a technical assessment of a selected program of projects may be conducted through modeling or other means to demonstrate the emissions reduction projection required under this section.

(1) In general.— At the discretion of a metropolitan planning organization, a technical assessment of a selected program of projects may be conducted through modeling or other means to demonstrate the emissions reduction projection required under this section.

(2) Applicability.— If an assessment described in paragraph (1) successfully demonstrates an emissions reduction, all projects included in such assessment shall be eligible for obligation under this section without further demonstration of emissions reduction of individual projects included in such assessment.

In any State with a population density of 80 or fewer persons per square mile of land area, based on the most recent decennial census, the requirements under subsection (g)(3) and paragraphs (1) and (2) of this subsection shall not apply to a nonattainment or maintenance area in the State if—

(1) In general.— For any State that has a nonattainment or maintenance area for fine particulate matter, an amount equal to 25 percent of the funds apportioned to each State under section 104(b)(4) for a nonattainment or maintenance area that are based all or in part on the weighted population of such area in fine particulate matter nonattainment shall be obligated to projects that reduce such fine particulate matter emissions in such area, including diesel retrofits.

(2) Construction equipment and vehicles.— In order to meet the requirements of paragraph (1), a State or metropolitan planning organization may elect to obligate funds to install diesel emission control technology on nonroad diesel equipment or on-road diesel equipment that is operated on a highway construction project within a PM2.5 nonattainment or maintenance area.

In any State with a population density of 80 or fewer persons per square mile of land area, based on the most recent decennial census, the requirements under subsection (g)(3) and paragraphs (1) and (2) of this subsection shall not apply to a nonattainment or maintenance area in the State if—

(A) Exception.—In any State with a population density of 80 or fewer persons per square mile of land area, based on the most recent decennial census, the requirements under subsection (g)(3) and paragraphs (1) and (2) of this subsection shall not apply to a nonattainment or maintenance area in the State if— (i) the nonattainment or maintenance area does not have projects that are part of the emissions analysis of a metropolitan transportation plan or transportation improvement program; and (ii) regional motor vehicle emissions are an insignificant contributor to the air quality problem for PM2.5 in the nonattainment or maintenance area.

(B) Calculation.— If subparagraph (A) applies to a nonattainment or maintenance area in a State, the percentage of the PM2.5 set-aside under paragraph (1) shall be reduced for that State proportionately based on the weighted population of the area in fine particulate matter nonattainment.

(4) Port-related equipment and vehicles.— To meet the requirements under paragraph (1), a State or metropolitan planning organization may elect to obligate funds to the most cost-effective projects to reduce emissions from port-related landside nonroad or on-road equipment that is operated within the boundaries of a PM2.5 nonattainment or maintenance area.

Each metropolitan planning organization serving a transportation management area (as defined in section 134) with a population over 1,000,000 people representing a nonattainment or maintenance area shall develop a performance plan that—

Each metropolitan planning organization serving a transportation management area (as defined in section 134) with a population over 1,000,000 people representing a nonattainment or maintenance area shall develop a performance plan that—

(A) includes an area baseline level for traffic congestion and on-road mobile source emissions for which the area is in nonattainment or maintenance;

(B) describes progress made in achieving the air quality and traffic congestion performance targets described in section 150(d); and

(C) includes a description of projects identified for funding under this section and how such projects will contribute to achieving emission and traffic congestion reduction targets.

(2) Updated plans.— Performance plans shall be updated biennially and include a separate report that assesses the progress of the program of projects under the previous plan in achieving the air quality and traffic congestion targets of the previous plan.

A State may obligate funds apportioned under section 104(b)(4) in an area of such State that is otherwise eligible for obligations of such funds for operating costs under chapter 53 of title 49 or on a system for which CMAQ funding was made available, obligated or expended in fiscal year 2012, or on a State-Supported [1] Amtrak route with a valid cost-sharing agreement under section 209 of the Passenger Rail Investment and Improvement Act of 2008 and no current nonattainment areas under subsection (d), and shall have no imposed time limitation.

(Added Pub. L. 93–87, title I, § 142(a), Aug. 13, 1973, 87 Stat. 272; amended Pub. L. 102–240, title I, § 1008(a), Dec. 18, 1991, 105 Stat. 1932; Pub. L. 102–388, title III, § 380, Oct. 6, 1992, 106 Stat. 1562; Pub. L. 104–59, title III, § 319(a)(1), (b), Nov. 28, 1995, 109 Stat. 588, 589; Pub. L. 104–88, title IV, § 405(a)(2), (b), Dec. 29, 1995, 109 Stat. 956, 957; Pub. L. 105–178, title I, § 1110(a)–(d)(1), June 9, 1998, 112 Stat. 142, 143; Pub. L. 109–59, title I, § 1808(a)–(f), Aug. 10, 2005, 119 Stat. 1461–1463; Pub. L. 112–141, div. A, title I, § 1113(a), (b), July 6, 2012, 126 Stat. 460; Pub. L. 113–76, div. L, title I, § 125, Jan. 17, 2014, 128 Stat. 587; Pub. L. 114–94, div. A, title I, §§ 1109(c)(5), 1114, Dec. 4, 2015, 129 Stat. 1343, 1348; Pub. L. 115–141, div. L, title IV, § 421, Mar. 23, 2018, 132 Stat. 1045.)