Transportation Planning 101

Most of these definitions were taken from the HATS/MPO’s plans as well as from the Federal Highway Administration. To view a more comprehensive listing of transportation planning terminology, visit the FHWA’s website.

The acronyms were derived from the HATS/MPO plans and from the Federal Highway Administration Correspondence Manual.

A (Brief) List of Transportation Acronyms

A • B • C • E • F • G • H • I • L • M • N • R • S • T • U • V


AASHTO – American Association of State Highway and Transportation Officials

A non-governmental organization that represents all modes of transportation in the United States, including air, water, highways, rail and transit. Website

ADA – Americans with Disabilities Act

A federal law enacted in 1990 (and amended in 2009) that prohibits discrimination based on disability. It defines the responsibilities and requirements to make transportation accessible to individuals with disabilities. 

ADHS – Appalachian Development Highway System

A federal program designed to expedite transportation improvements on major corridors in the Appalachian Region. Corridor V, which includes part of I-565 and US 72, runs through the Huntsville MPO study area. Website

AADT – Average Annual Daily Traffic

Also known as a “traffic count,” the average number of vehicles that use a road in one year, divided by the number of days in the year. 

ALDOT – Alabama Department of Transportation

The state agency assigned to design, schedule and bid transportation projects in Alabama. Projects on major roads such as Interstates, US Highways (e.g. Memorial Parkway, University Drive), and State Routes (e.g. Jordan Lane) are the responsibility of ALDOT. Website

AMPO – Association of Metropolitan Planning Organizations

A national non-profit organization established to serve the needs and interests of Metropolitan Planning Organizations. Website

ARC – Appalachian Regional Commission

A federal organization comprising of thirteen states (including Alabama) that make up the Appalachian Region. It provides funding for transportation and economic development projects in its service area. See also Appalachian Development Highway SystemWebsite


BTS – Bureau of Transportation Statistics

A division of the federal Department of Transportation, Research and Innovative Technology Administration (RITA) that provides data on interstate travel modes, such as air and freight. Website


CAA – Clean Air Act

A federal law that requires the Environmental Protection Agency (EPA) to enact and enforce regulations curbing air pollution. Of great importance to the MPO is the Act’s mandate on designating “Non-Attainment Areas,” or regions with a high amount of air pollution, where plans to curb pollution and congestion must be submitted with every major transportation project. Huntsville remains an “Attainment” area.  Website

CFR – Code of Federal Regulations

A publication of the general and permanent rules and regulations administered by the Federal government. Website

CMS – Congestion Management System

An outline, required for urbanized areas with over 200,000 residents, of plans to alleviate congestion in the study area. Website

COOP – Continuity of Operations Plan

A plan for the continuous operation of the Metropolitan Planning Organization in the event of an emergency. 

CSA- Combined Statistical Area

A group of MSAs and µSAs defined by the Office of Management and Budget (OMB) that have strong economic and cultural ties to one another, but do not meet the 25 percent commuting threshold of an M/µSA. M/µSAs are added to CSAs when 15 percent of their workforce commutes into the core county/counties of the MSA. The Huntsville-Decatur-Albertville Combined Statistical Area includes Madison, Morgan, Marshall, Limestone and Lawrence counties. See also Metropolitan Statistical Area and Micropolitan Statistical Area.

CTPP – Census Transportation Planning Package

A set of special transportation planning-related tabulations from the annual American Community Survey released by the Census Bureau. 


EIS – Environmental Impact Statement

A required report that details any adverse economic, social and environmental effects of a proposed transportation project where federal funds are being used.

EPA – Environmental Protection Agency

The federal agency responsible for administering and enforcing environmental laws. See also Clean Air Act. Website


FHWA – Federal Highway Administration

A branch of the federal Department of Transportation that administers the federal-aid Highway Program. Website

FONSI- Finding of No Significant Impact

A conclusion made by the federal Department of Transportation that a project will not have any significant impacts on the quality of the environment. 

FR – Federal Register

A daily publication of the US Government that contains public notices of new or proposed federal laws and regulations, or changes to existing rules. Website

FTA – Federal Transit Administration

A branch of the federal Department of Transportation that is the principal source of federal financial assistance for planning, development, and improvement of public and mass transportation systems. Website

FY – Fiscal Year

The yearly accounting period, which begins on October 1st. Fiscal years are denoted by the calendar year in which they end– for example, FY 2014 began on October 1, 2013 and ended on September 30, 2014.


GIS – Geographic Information Systems

A way to create, view, and analyze maps and data on a computer. 

GPS – Global Positioning System

A satellite-based navigation system that provides location and time information anywhere on or near the earth. 


HOV – High Occupancy Vehicle

A vehicle carrying two or more people. Many states use HOV lanes, also known as “carpool” or “express” lanes, as an incentive to reduce the number of Single-Occupancy Vehicles (SOVs) on highways.


ITS – Intelligent Transportation System

The application of advanced technologies to improve the efficiency and safety of transportation systems, such as cameras, dynamic message signs, etc. 

ISTEA – Intermodal Surface Transportation Efficiency Act of 1991

A federal transportation funding program implemented in FY 1992 that required regional long-range transportation plans and increased emphasis on public participation and transportation alternatives. Replaced in 1998 by TEA-21.


LOS – Level of Service

An assessment of a road’s operating conditions using a grading system, with LOS A being the lowest level of congestion (free flow) and LOS F being the highest.  

LRTP – Long Range Transportation Plan

A document describing the MPO’s vision for regional transportation and the schedule for funding projects over the next 25 years. The Huntsville MPO schedules an update of the LRTP every five years, with the next update scheduled for 2025. Website


MAP-21 – Moving Ahead for Progress in the 21st Century Act

The current federal transportation funding bill, implemented in 2012.

MOU – Memorandum of Understanding

A document providing a general description of the responsibilities that are to be assumed by two or more parties in the pursuit of some goal. 

MPO – Metropolitan Planning Organization

A regional policy body, required for urban areas with populations of 50,000 or more and designated by local and state government. Is responsible, in cooperation with the state Department of Transportation and regional partners, for carrying out requirements of federal metropolitan planning legislation. 

MSA – Metropolitan Statistical Area

Areas (typically a county or groups of counties) defined by the Office of Management and Budget (OMB) that have either a city and/or an urbanized area of at least 50,000 residents. Counties are added to MSAs when 25 percent of their workforce commutes into the core county/counties of the MSA. The Huntsville Metropolitan Statistical Area includes Madison and Limestone counties. See also Combined Statistical Area and Micropolitan Statistical Area.

µSA – Micropolitan Statistical Area

Areas (typically a county or groups of counties) defined by the Office of Management and Budget (OMB) that have either a city and/or an urban area between 10,000 and 49,999 residents. µSAs in the Huntsville region include the Scottsboro Micropolitan Statistical Area, which includes Jackson County, and the Albertville Micropolitan Stastical Area, which includes Marshall County. See also Metropolitan Statistical Area and Combined Statistical Area.


NAAQS – National Ambient Air Quality Standards

Federal standards that set allowable concentrations and exposure limits for various pollutants, such as ozone or particulate matter.

NEPA – National Environmental Policy Act

A federal law passed in 1969 that requires any project using federal funding must examine the effects of proposed changes to the environment. See also Environmental Impact Statement.

NHS – National Highway System

A system of federally-designated and approved highways established in 1995. This network includes the Interstate Highway System, as well as other roads that connect to major transportation facilities (such as airports or rail stations) and military bases. 


RFP – Request for Proposals

An advertisement to businesses to submit bids and documents related to a specific plan or project.

ROW – Right-of-Way

Land acquired for or devoted to transportation purposes. 


SAFETEA – Safe, Accountable, Flexible and Efficient Transportation Equity Act 

A federal transportation funding bill that was signed into law in 2005. It was replaced by MAP-21 in 2012.

SOV – Single Occupant Vehicle

A vehicle carrying only the driver. See also High Occupancy Vehicle.

SPR – State Planning and Research Funds

The primary source of funding for statewide long-range planning. 

SR – State Route

A road that is maintained by the state Department of Transportation. This includes state roads (such as Alabama Highway 53, or AL-53) as well as interstates and US Highways.


TEA-21 – Transportation Equity Act for the 21st Century

A federal transportation funding bill signed into law in 1998. It was replaced by SAFTEA in 2005. 

TIP – Transportation Improvement Program

A document prepared by the MPO that lists projects to be federally-funded over the next five years. See also Long-Range Transportation Plan.

TMA – Transportation Management Area

A designation given to all urban areas with a population of over 200,000. Huntsville was designated a TMA after the 2000 Census. 

TVA – Tennessee Valley Authority

The public electricity producer for the Huntsville region. Also provides assistance in river navigation, flood control, and economic development projects in the Tennessee River watershed. Website


USC – United States Code
Formally known as the Code of Laws of the United States of America. It is a compilation and codification of federal laws that is published every six years. Website


V/C – Volume/Capacity Ratio

The ratio of the current or projected demand flow to the capacity of a transportation facility.

VMT – Vehicle Miles Traveled/Vehicle Miles of Travel

The number of miles traveled by vehicles for a period of one year. 

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