Following are key dates in the 26-year saga of I-66:

Oct. 4, 1956: I-66 is proposed by the Virginia Highway Commission as a 76-mile link between Washington and another planned interstate, I-81.

Aug. 14, 1958: Highway building companies submit bids on the first section of I-66, a 3.3-mile stretch near Marshall in Fauquier County. Construction begins in autumn.

Nov. 18, 1964: The first 12.9-mile section of I-66 in the metropolitan Washington area is opened to traffic, connecting the Capital Beltway with Centreville in Fairfax County. (Other portions of I-66 west of the Beltway had opened as early as 1961.)

Nov. 9, 1967: Virginia highway officials, after several years of delay, formally agree to postpone construction of a section of I-66 through Arlington County for two more years to allow Washington-area transit officials to plan for a possible rapid-rail line along the I-66 median.

Sept. 29, 1970: Widespread opposition to I-66 surfaces among Arlington residents at a public hearing, quickly leading to formation of the Arlington Coalition on Transportation, a citizens' group that will fight the highway in the years to come.

Feb. 19, 1971: The Arlington coalition and other highway opponents file a lawsuit in U.S. District Court in Alexandria seeking to block construction of I-66 through the county.

April 4, 1972: The 4th U.S. Circuit Court of Appeals in Richmond bars construction of I-66 through Arlington until highway officials hold new hearings and prepare an environmental impact statement.

Aug. 1, 1975: Secretary of Transportation William T. Coleman Jr., after reviewing testimony from the hearing and other data, prohibits construction of I-66 between the Capital Beltway and the Potomac River.

March 8, 1976: Virginia highway officials propose a scaled-down, four-lane version of I-66 that will be restricted during rush hours to car pools, buses and Dulles International Airport traffic.

Aug. 4, 1976: The board of directors of the Metropolitan Washington Council of Governments endorses the scaled-down I-66 proposal by a weighted vote of 66 1/2 to 54 1/2 after a sometimes-bitter debate among city and suburban officials.

Jan. 5, 1977: Transportation Secretary Coleman approves construction of the restricted, four-lane version of I-66 in exchange for Virginia's agreement to allocate millions of dollars in federal highway aid to help complete the Metro transit system.

April 11, 1980: Court challenges by highway opponents end as the 4th U.S. Circuit Court of Appeals rejects a final lawsuit brought by a citizens' group called Continued Action on Transportation.

Dec. 22, 1982: The last 10-mile section of I-66 opens between the Beltway and the Theodore Roosevelt Bridge.