A metropolitan planning organization (MPO) is a federally mandated and federally funded transportation policy-making organization in the United States that is made up of representatives from local government and governmental transportation authorities.
 MPOs were introduced by the Federal-Aid Highway Act of 1962, which required the formation of an MPO for any urbanized area (UZA) with a population greater than 50,000.
 Federal funding for transportation projects and programs are channeled through this planning process.
 Congress created MPOs in order to ensure that existing and future expenditures of governmental funds for transportation projects and programs are based on a continuing, cooperative, and comprehensive (“3‑C”) planning process.
 Statewide and metropolitan transportation planning processes are governed by federal law ( /134 §§ 134 –/135 135  ).
 Transparency through public access to participation in the planning process and electronic publication of plans now is required by federal law.
 As of 2015, there are 408 MPOs in the United States.
The Federal-Aid Highway Act of 1956, popularly known as the National Interstate and Defense Highways Act (Public Law 84-627), was enacted on June 29, 1956, when President Dwight D. Eisenhower signed the bill into law.
 With an original authorization of US$25 billion for the construction of 41,000 miles (66,000 km) of the Interstate Highway System supposedly over a 10-year period, it was the largest public works project in American history through that time.
The United States Congress is the bicameral legislature of the federal government of the United States consisting of two chambers: the Senate and the House of Representatives.
The U.S. federal-aid highway program was commenced in 1916, with milestones of Federal-Aid Highway Act of 1944 and Federal Aid Highway Act of 1956.
The Federal-Aid Highway Act of 1973 (Public Law 93–87; 87 Stat.
 250) is legislation enacted by the United States Congress and signed into law on August 13, 1973, which provided funding for existing interstate and new urban and rural primary and secondary roads in the United States.
 It also funded a highway safety improvement program, and permitted states for the first time in U.S. history to use Highway Trust Fund money for mass transit.
 The law also established the first national speed limit (of 55 mph ).
The Amethyst Initiative is an organization made up of U.S. college presidents and chancellors that in July 2008 launched a movement calling for the reconsideration of U.S. legal drinking age, particularly the minimum age of 21.
 The National Minimum Drinking Age Act of 1984 requires all US states to raise their minimum age for purchase and public possession of alcohol to 21 or face a reduction in highway funds under the Federal-Aid Highway Act.
 The Amethyst Initiative was initiated by John McCardell, founder of Choose Responsibility, a former professor of history at Middlebury College in Middlebury, Vermont and current Vice-Chancellor of , and is currently supported by 136 college presidents who signed a statement proclaiming, "It’s time to rethink the drinking age".
Tamil Nadu Legislative Council was the upper house of the bicameral legislature of the Indian state of Tamil Nadu.
 It began its existence as Madras Legislative Council, the first provincial legislature for Madras Presidency.
 It was initially created as an advisory body in 1861, by the British colonial government.
 It was established by the first Indian Council Act of 1861, enacted in the British parliament in the aftermath of the Indian Rebellion of 1857.
 Its role and strength were later expanded by the second Council Act of 1892.
 Limited election was introduced in 1909.
 The Council became a unicameral legislative body in 1921 and eventually the upper chamber of a bicameral legislature in 1937.
 After India became independent in 1947, it continued to be the upper chamber of the legislature of Madras State, one of the successor states to the Madras Presidency.
 It was renamed as the Tamil Nadu Legislative Council when the state was renamed as Tamil Nadu in 1969.
 The Council was abolished by the M. G. Ramachandran administration on 1 November 1986.
 In 2010 the DMK regime headed by M. Karunanidhi tried to revive the Council.
 The current AIADMK regime has expressed its intention not to revive the council and has passed a resolution in the Tamil Nadu Legislative Assembly in this regard.
The Federal-Aid Highway Act of 1968 (Public Law 90-495; 82 Stat.
 815) is legislation enacted by the United States Congress and signed into law on August 24, 1968, which expanded the Interstate Highway System by 1500 mi ; provided funding for new interstate, primary, and secondary roads in the United States; explicitly applied the environmental protections of the Department of Transportation Act of 1966 to federal highway projects; and applied the Davis–Bacon Act to all highway construction funded by the federal government.
 It established three new programs: a National Bridge Inspection Program, funding and fair housing standards for those displaced by federally funded highway construction, and a traffic operations study program.
The Federal-Aid Highway Act of 1952 authorized $25 million for the Interstate Highway System on a 50–50 matching basis, meaning the federal government paid 50% of the cost of building and maintaining the interstate while each individual state paid the balance for interstate roads within their borders.
The Federal-Aid Highway Act of 1944 (Pub.
 L. No. 78-521; 58 Stat.
 838) is legislation enacted by the United States Congress and signed into law on December 20, 1944, which established a 50-50 formula for subsidizing the construction of national highways and secondary (or "feeder") roads.
 The legislation established a National System of Interstate Highways, and required the Public Roads Administration to establish construction and operational standards for the Interstate Highway System.

Question: What was expanded by the US bicameral legislature by the Federal-Aid Highway Act of 1968?
Answer: Interstate Highway System