Unbuilt Interstate 266:

1964 Plan II

Plan II from the September 1964 Interstate 266 study had the highway diverging from Interstate 66 east of the proposed overpass of Spout Run Parkway. Interstate 266 would then parallel Spout Run Parkway through the Spout Run Valley. A portion of Interstate 266 in this area would be in a tunnel. According to the document, the tunnel was proposed to help nullify potential community opposition and to help preserve the natural characteristics of the Spout Run area. After emerging from the tunnel, Interstate 266 would cross over the George Washington Memorial Parkway and the Potomac River on Three Sisters Bridge. The bridge would be named for Three Sisters Island which is located just north of the proposed crossing. An interchange at Georgetown University would provide downstream connections to the Potomac Freeway. Upstream connections would be provided to MacArthur Boulevard and Foxhall Road, both local streets. No upstream connections would be provided to the Potomac Freeway. The document noted these connections could be added for a nominal cost if needed. On the Virginia side, Interstate 266 traffic headed towards Interstate 266 could exit onto Spout Run Parkway.

This map details Plan II:

The 1964 Plan also included artists renderings of the proposals.

Above: Plan II looking north towards Washington, DC. Interstate 266 comes in from the lower left hand corner of the picture. Georgetown University is at the top center of the picture. The Potomac Freeway runs left to right in the top third of the picture.

Left: Plan II in the Spout Run Area looking north towards Washington, DC. You can see Interstate 266 going towards the top left of the picture as it goes through its tunnel in the Spout Run Valley. Interstate 66 is coming from the bottom of the picture and then turning right towards the top right. The road crossing under Interstate 66 in the lower left of the picture is Lee Highway (US 29). The route going over Interstate 66 is an expanded Spout Run Parkway. Key Bridge is barely visible in the extreme upper right of the picture.

The summary of estimated costs for Plan II was as follows:

Item	Cost
Approach - Virginia Side	$16,790,000
Approach - DC Side	12,089,000
Potomac River Bridge	5,675,000
Right of Way - Virginia Side	10,379,000
Right of Way - District Side	8,302,000
Contingencies at 10%	5,414,000
	================
Grand Total	57,679,000

Plan II with several modifications was studied further in 1973 as apart of an Interstate 66 Corridor Study. The modifications are as follows:

No tunnel in the Spout Run Valley.
Spout Run Parkway goes under Interstate 66 instead of over it.
Interstate 266 replaces the northbound Spout Run Parkway. The southbound lanes retain their original alignment.
Ramps to and from Interstate 266 go under Interstate 66 where needed instead of over it.
On the District side of the Potomac River, the Potomac Freeway has been eliminated. Therefore, Interstate 266 turns east towards Georgetown with no local connections.

Full details of the 1973 study along with map scans are on the main Unbuilt Interstate 266 page.

Source:

Connecting I-66 in Virginia with the Potomac River Freeway in the District of Columbia via an Additional Potomac River Bridge (Location Studies : Interstate Route 266). Howard, Needles, Tammen and Bergendoff Consulting Engineers. September 1964.

Please send any updates, comments and corrections to Michael Hale.

Back to the Main Unbuilt Interstate 266 Page

Last Update: 1/28/08