Glossary

AASHTO’s Materials Reference Laboratory (AMRL)—Housed at the National Institute of Standards and Technology in Gaithersburg, Maryland, AMRL promotes adherence to standards in the testing of construction materials by
laboratories serving the transportation industry.


American Recovery and Reinvestment Act of 2009 (ARRA)—The $787 billion economic stimulus package passed by Congress on February 13, 2009. The legislation provided $48 billion for transportation—$27.5 billion for highways; $8.4 billion for transit; and $8 billion for high-speed and intercity passenger rail projects.


A Policy on Geometric Design of Highways and Streets (The “Green Book”)— An AASHTO publication that provides the fundamental framework for the design of roadways and associated features in rural and urban settings.  


Appropriations—An act of a legislative body that makes funds available for expenditures with specific limitations as to amount, purpose, and period.Congress regularly has to pass 12 annual appropriations bills, including funding
for the U.S. Department of Transportation.


Apportionments—An administrative assignment of funds based on a prescribed formula by a governmental unit to another governmental unit for specific purposes and for certain periods.


Authorization—State legislatures and Congress pass legislation creating or renewing Federal or state programs with a specified funding amount.

Bridge Replacement and Rehabilitation—The Highway Bridge Replacement and Rehabilitation Program (HBRRP) provides funds to assist states in their programs to replace or rehabilitate deficient highway bridges and to seismic
retrofit bridges located on any public road.


Categorical Exclusions—With regard to the National Environmental Policy Act of 1969, a categorical exclusion means a category of actions that do not individually or cumulatively have a significant effect on the human environment; therefore making neither an environmental assessment nor an environmental impact statement required.


Clean Air Act—The Clean Air Act (CAA) is the comprehensive Federal law that regulates air emissions from area, stationary, and mobile sources. The law authorizes National Ambient Air Quality Standards (NAAQS) to protect public
health and the environment.

Congestion Mitigation and Air Quality—As part of the Clean Air Act, the CMAQ program is jointly administered by the Federal Highway Administration and the Federal Transit Administration (FTA) to provide funds to state transportation agencies, Metropolitan Planning Organizations and transitagencies to invest in projects that reduce criteria air pollutants regulated from transportation-related sources.


Context Sensitive Solutions—A collaborative, interdisciplinary approach that involves all stakeholders to develop a transportation facility that fits its physical setting and preserves scenic, aesthetic, historic, and environmental resources, while maintaining safety and mobility. CSS is an approach that considers the total context within which transportation improvement projects will exist.


Contract Authority—Funds obligated to state transportation departments prior to appropriations. The Federal Highway Administration notes that most Federal-aid highway programs operate under contract authority.


Core Highway Program—Made up of the National Highway System, Interstate Maintenance, Surface Transportation Program, Bridge Replacement and Rehabilitation, and Congestion Mitigation and Air Quality Improvement programs.


Dedicated Funds—1) Funds allocated to a given area usually by some formula and made available on an annual basis. 2) Funds collected for a specific program or purpose.


Design Speed—A selected speed used to determine the various geometric design features of the roadway. The assumed design speed should be a logical one with respect to the topography, anticipated operating speed, the adjacent land use, and the functional classification of highway.


Discretionary Spending—Spending set by annual appropriation levels made by decision of Congress. This spending is optional, and in contrast to entitlement programs for which funding is mandatory.


Earmark—Funds dedicated for a specific program or purpose by a legislator. Revenues are earmarked by law. Expenditures are earmarked by appropriations bills or reports.


Environmental Impact Statement (EIS)—Part of the National Environmental Policy Act of 1969, an EIS is a document that must be filed when the Federal government takes a “major Federal action significantly affecting the quality of the human environment.”

Federal-Aid Highway—A highway eligible for assistance under Title 23 United StatesCode other than a highway classified as a local road or rural minor collector.


Federal-Aid System—Any of the Federal-aid highway systems described in Title 23 Section 103.


Federal Operating Assistance—Funds authorized by the Federal government to assist in paying the cost of operating transit services.


Firewall—A tool to prevent savings in one category from being applied toward increased spending in another.


Highway Safety Manual—A 2010 publication that features tools for considering safety in the project development process. This manual was produced through a joint effort between AASHTO, the Federal Highway Administration (FHWA), and the Transportation Research Board. Two additional chapters on freeways and interchanges to be published in July 2014.


Highway Trust Fund—Created by the Highway Revenue Act of 1956 (Pub. L. 84-627), primarily to ensure a dependable source of financing for the National System of Interstate and Defense Highways and also as the source of funding for the remainder of the Federal-aid highway program. Of the 18.4 cent-pergallon Federal tax on gasoline, 15.44 cents goes into the highway account, 2.86 cents into the Mass Transit Account and 0.1 cent into the Leaking Underground Storage Tank fund administered by the U.S. Environmental Protection Agency. Diesel is taxed at 24.4 cents per gallon.


Intermodal Planning Group (IPG)—A regional organization of Federal agencies set up to oversee transportation planning activities in the states of that region. It might include representatives of the Federal Highway Administration, Coast Guard, Federal Aviation Administration, Federal Railroad Administration, Federal Transit Administration, Department of Housing and Urban Development, Environmental Protection Agency, and other
Federal agencies.


Interstate Maintenance—The Interstate Maintenance program provides funding to states for resurfacing, restoring, rehabilitating, and reconstructing most routes on the Interstate Highway System. Funds are subject to the overall
Federal-aid obligation limitation. A state may transfer up to 50 percent of its IM apportionment to its National Highway System, Surface Transportation,Congestion Mitigation and Air Quality Improvement, Highway Bridge
Replacement and Rehabilitation, or Recreational Trails apportionment.

Interstate Highway System—A 47,000-mile network of roadways founded in 1956 with the passage of the Federal-Aid Highway Act. It is officially called the Dwight D. Eisenhower System of Interstate and Defense Highways.


Interstate Substitution Transfer Project—Formerly non-highway public transportation projects financed by funds which would otherwise have been spent on a segment of the Interstate highway system. New amendments to the
Federal- Aid Highway Act allow the funds to be used for highways and street improvement projects as well as for public transportation projects.


Intelligent Transportation Systems (ITS)—A broad range of wireless and wire line communications-based information and electronics technologies. When integrated into the transportation system’s infrastructure, and in vehicles themselves, these technologies relieve congestion, improve safety, and enhance American productivity. ITS is made up of 16 types of technology-based systems. These systems are divided into intelligent infrastructure systems and intelligent vehicle systems.


Load and Resistance Factor Design (LRFD)—AASHTO bridge design manual introduced in 1994.


Manual on Uniform Traffic Control Devices (MUTCD)—Defines the standards used by road managers nationwide to install and maintain traffic control devices on all streets and highways. The MUTCD is published by the Federal Highway Administration (FHWA) under 23 Code of Federal Regulations (CFR), Part 655, Subpart F.


Match—State or local funds required by the Federal government to complement Federal funds for a project. For example, in the case of public transportation, the Federal government may provide 80 percent of the necessary funds if the state or local government matches 20 percent. For interstate highway projects, the Federal government provides 90 percent of the funds, and state or local government pays the 10 percent matching cost. A match may also be required by states in funding projects which are a joint state/local effort.


Metropolitan Planning Organizations (MPO)—The organization designated by the governor as responsible together with the state for transportation planning in an urbanized area according to 23 USC 134. This organization is the forum for cooperative decision-making by principal elected officials of general local government.

Metropolitan Transportation Plan—Metropolitan Planning Organizations, in cooperation with states and such transportation providers as public transit operators, carries out the metropolitan transportation planning process. That includes development of the transportation plan and the Transportation Improvement Plan.


Moving Ahead for Progress in the 21st Century Act (MAP-21)—Signed into law by President Barrack Obama on July 6, 2012, it is scheduled to expire on October 1, 2014. MAP-21 reauthorizes the Federal-aid highway program at approximately $105 billion for fiscal years (FY) 2013 and 2014. It consolidates the number of Federal programs by two-thirds to focus resources on key national goals, reduce duplication, and increase the accountability and transparency of investment decision-making through performance-based planning and programming. The legislation also eliminates earmarks, expedites project delivery, and strengthens the Transportation Infrastructure Finance 
and Innovation Program (TIFIA) to leverage additional Federal dollars for transportation projects.


National Cooperative Highway Research Program (NCHRP)—Administered by the Transportation Research Board (TRB) and sponsored by the member departments of AASHTO in cooperation with the Federal Highway Administration (FHWA), the National Cooperative Highway Research Program (NCHRP) was created in 1962 as a means to conduct research in acute problem areas that affect highway planning, design, construction, operation, and maintenance nationwide.


National Environmental Policy Act of 1969—NEPA’s basic policy is to assure that all branches of government give proper consideration to the environment prior to undertaking any major Federal action that significantly affects the environment. NEPA requirements are invoked when airports, buildings, military complexes, highways, parkland  purchases, and other Federal activities are proposed. Environmental Assessments (EAs) and Environmental Impact Statements (EISs), which are assessments of the likelihood of impacts from alternative courses of action, are required from all Federal agencies and are the most visible NEPA requirements. Section 106 of NEPA deals with historic preservation.


National Highway System—Approximately 160,000 miles of roadway important to the nation’s economy, defense, and mobility. The National Highway System includes the interstate system, principal arterials, Strategic Highway Network, Major Strategic Highway Network Connectors and intermodal connectors.

Obligation Authority—Total amount of funds that may be obligated to states in a year. For the Federal-aid highway program this is comprised of the obligation limitation amount plus amounts for programs exempt from the limitation.


Obligation Limitation—The maximum amount of Federal assistance that may be promised during a specified time period. This is a statutory budgetary control that does not affect the apportionment or allocation of funds. It controls
the rate at which these funds may be used.


Rescission—A cancellation of previously approved but unspent funds. Congress or the president may propose it. R scissions must receive approval from Congress within 45 days of the request to cancel allotted funds. Since Fiscal Year 2002, states have rescinded more than $13 billion.


Revenue Aligned Budget Authority—Annual funding adjustment to the highway program started in Fiscal Year 2000. The firewall level is adjusted to reflect revised receipts estimates for the Highway Account of the Highway Trust Fund. Then, adjustments—equal to the firewall adjustment—are made to the Federal-aid highway authorizations and obligation limitation for the fiscal year. This can either boost or cut Federal funding to states. 

Revolving Fund—Working capital established to facilitate operations of special functions, which is replenished by reimbursement from other funds.


Safe, Accountable, Flexible and Efficient Transportation Equity Act—A Legacy for Users (SAFETEA-LU) (Public Law 109-59)—Passed in 2005, it authorizes Federal surface transportation programs through Fiscal Year 2009. SAFETEA-LU is authorized at $286.4 billion for Federal highway, transit, freight, research, safety, intelligent  transportation systems, and environment and planning programs. Congress has temporarily extended SAFETEA-LU pending the enactment of a new authorization.


Short Line Railroad—1) A company that originates and/or terminates freight traffic, participates in division of revenue, and is normally less than 100 miles in length. 2) Class III railroads that receive less than $40 million a year in operating revenue and have less than 350 miles of track.


State Funds—Funds obtained under the authority of the state or any political or other subdivision thereof, and made available for expenditure under the direct control of the state highway department.

State Implementation Plan—A state plan for complying with the Federal Clean Air Act, administered by the Environmental Protection Agency. The SIP consists of narrative, rules, technical documentation, and agreements that an individual state will use to clean up polluted areas.


State Implementation Plan—Federal clean air laws require areas with unhealthy levels of ozone, carbon monoxide, nitrogen dioxide, sulfur dioxide and inhalable particulate matter to develop State Implementation Plans (SIPs), describing how they will attain National Ambient Air Quality Standards (NAAQS).


State Operating Assistance—Funds obtained from one or more state governments to assist in paying the cost of operating transit services.


Strategic Highway Research Program (SHRP 2)—To address the challenges of moving people and goods efficiently and safely on the nation’s highways, Congress created the second Strategic Highway Research Program known as SHRP 2. This targeted, short-term research program involves the collaborative efforts of the Federal Highway Administration, AASHTO, and the Transportation Research Board. The program addresses four strategic focus areas—the role of human behavior in highway safety (Safety); rapid highway renewal (Renewal); improved travel time reliability through congestion reduction (Reliability); and transportation planning that better integrates community, economic, and environmental considerations into new highway capacity (Capacity).


Surface Transportation Improvement Program—A list of transportation projects for which Federal funding will be sought over a three- to five-year period. It describes transportation improvements to be funded by public funds from all sources, with a budget for each project. The first year’s transportation projects are called the annual element. Federal legislation requires that each state develop one multimodal Statewide Transportation Improvement Program
(STIP) for all areas of the state.


Transportation Improvement Program (TIP)—A list of transportation projects for which funding will be sought over a three- to five-year period. It describes transportation improvements to be funded by public funds from all sources, with a budget for each project. The first year’s transportation projects are called the annual element.


Transportation Plan—A program of action to provide effectively for present and future demands for movement of people and goods. This program must necessarily include consideration of the various modes of travel.

Transportation Research Board (of the National Academies of Sciences) (TRB)—The mission of the Transportation Research Board is to provide leadership in transportation innovation and progress through research and information exchange, conducted within a setting that is objective, interdisciplinary, and multimodal.


Transportation System Management (TSM)—An emphasis on small physical improvements and operational  efficiencies to the transportation system in order to positively affect mobility.


Unified Planning Work Program (UPWP)—A document that is produced annually by metropolitan planning organizations that describes transportation-related planning activities that will be carried out during the next year.


Urban Transportation Planning Process—The Federally required planning process in urbanized areas aimed at developing programs to meet a region’s transportation needs through analyzing the existing system and preparing plans and studies in a comprehensive, continuing, and cooperative manner.


Urbanized Area (UZA)—A geographic area with a population of 50,000 or more designated by the Census Bureau as having met certain criteria of population size or density.


Weigh-in-Motion (WIM)—A set of sensors and supporting instruments that measures the presence of a moving vehicle and the related dynamic tire forces at specified locations with respect to time; estimates tire loads, speed, axle spacing, vehicle class according to axle arrangement, and other parameters (Sources—AASHTO, Federal Highway Administration, C-SPAN Congressional Glossary, Northeast-Midwest Institute, Transportation Research Board).