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Guide to the
Capital Beltway


VDOT Traffic Cameras with Interactive Map


Capital Beltway History

The Capital Beltway is the 64-mile-long Interstate freeway that encircles Washington, D.C., passing through Virginia and Maryland, carrying the Interstate I-495 designation throughout, and carrying the overlapping Interstate I-95 designation on the eastern portion of the Beltway.


Formal planning for the Beltway began in 1950, and it was included as part of the national Interstate Highway System in the Federal Aid Highway Act of 1956 (which authorized the construction of a 41,000-mile national system of Interstate highways), and construction of the Beltway began in 1957. The most commonly used planning name for the highway was the Washington Circumferential Highway, and in June 1960 the highway was officially named "Capital Beltway" by both states. The I-495 Capital Beltway was fully completed when its final Maryland segment was opened to traffic on August 17, 1964.

The Beltway made its first formal appearance on regional planning documents, when it appeared on maps and in a one-sentence reference in the 1950 “Comprehensive Plan” for the Washington area, by the National Capital Park and Planning Commission (NCPPC). This document was published in 1952. The Maryland - National Capital Planning Commission (M-NCPC) approved the entire concept. In 1954 the planning board of Fairfax County, Virginia, approved a master highway plan that included the beltway, thus completing the official local approvals of the NCPPC plan for the beltway.

The Capital Beltway is 63.8 miles long, with 22.1 miles in Virginia, and 41.7 miles in Maryland. When originally completed, the Beltway was six lanes wide (three each way) for 49.3 miles between I-95 in Virginia, around the south, east and north of Washington, to the Virginia terminus of the northern Potomac River bridge, and the Beltway was four lanes wide (two each way) for 14.5 miles between the northern Potomac River bridge and I-95 at Springfield, Virginia. So all of the 41.7 miles of the Beltway in Maryland, including both Potomac River bridges, had six lanes; and in Virginia, 7.6 miles of the Beltway had six lanes and 14.5 miles had four lanes. All 33.7 miles of the Beltway east of the two I-95 junctions, had six lanes. The above lengths are to the tenth of a mile, and for convenience sake, in most places in this article, lengths are rounded to the nearest mile.

In the span of 1972 to 1992, through various widening projects, nearly the entire Beltway was widened to eight lanes (four each way), including the entire 14.5 mile section in Virginia that was originally four lanes. In 1972, Maryland completed Beltway widening to eight lanes (four each way) between MD-210 Indian Head Highway and MD-97 Georgia Avenue, a distance of 29 miles. In 1977, Virginia completed Beltway widening to eight lanes between US-1 Jefferson Davis Highway and VA-193 Georgetown Pike, a distance of 21 miles. In 1990, Maryland completed Beltway widening to eight lanes between MD-97 Georgia Avenue and I-270/MD-355, a distance of 4 miles. In 1991-92, Maryland and Virginia completed Beltway widening to eight lanes between I-270 Spur and VA-193, a distance of 5 miles; this included the American Legion Memorial Bridge and approaches to each interchange closest to the river, which was widened to 10 lanes. The 3 miles of Beltway between I-270/MD-355 and I-270 Spur is adequate at six lanes, as the traffic volume is about 1/2 of that of the adjoining sections of the Beltway. The only other Beltway segment not widened to at least eight lanes, was the southern Potomac River bridge (Woodrow Wilson Bridge), and 1/2 mile of Beltway on either end of the bridge, which was built with six lanes (three each way), although widening is now under construction and the Beltway will be reconstructed to a 10- to 12-lane highway for 7.5 miles between west of VA-241 Telegraph Road and east of MD-210 Indian Head Highway, including constructing a new 12-lane Woodrow Wilson Bridge.

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Location and Design of Capital Beltway

Maryland and Virginia highway officials needed to directly coordinate on the task of determining the location of the two Potomac River bridges for the proposed circumferential highway that would completely bypass the District of Columbia and Arlington, and these two locations were conceptually determined as far back as the early 1930s in studies by committees of highway officials and professional planners from Washington, Maryland and Virginia, for proposed bypasses around Washington; and these two crossings were proposed to be a bridge at Alexandria and a bridge east of Great Falls, Virginia. These bridges needed to cross the Potomac River at or near to a right angle to minimize the length of the bridge as much as feasible, and they needed to be located at a place where each state could build a high-speed highway approach to each bridge. The rest of the circumferential highway was generally planned independently by each state, with little actual coordination between the states. The proposed Washington circumferential highway was formally approved locally in the actions in 1950 by the National Capital Park and Planning Commission (NCPPC), in 1952 by the Maryland - National Capital Planning Commission (M-NCPC), and in 1954 by Fairfax County and the City of Alexandria, and federally as an authorized and funded Interstate highway in 1956, and the approved alignment was fairly similar to what was ultimately constructed. The Maryland State Roads Commission (SRC) administered the design, right-of-way acquisition, and construction of the 41-mile Maryland section of the Beltway; the Virginia Department of Highways (VDH) administered the design, right-of-way acquisition, and construction of the 22-mile Virginia section of the Beltway; and the federal Bureau of Public Roads (BPR) administered the design and construction of the one-mile Potomac River bridge (Woodrow Wilson Memorial Bridge) at Alexandria. The SRC and VDH basically did operate independently of each other from the final design phase onward in the development of the Beltway, but at the same time, after the federal 1956 Interstate Highway System approval, they had a fairly clear picture of what the other state would build, as far as the general corridor (say, 1-mile wide corridor) where the other state would build the Beltway.

The "Yellow Book", formally named the General Location of National System of Interstate Highways, was published by the Bureau of Public Roads (BPR) in 1955, and it showed the official preliminary location of the urban Interstate highways, along with the loop Interstates and spur Interstates that were in addition to the mainline Interstate highways. The Yellow Book was provided to members of the U.S. Congress as the debates were underway that would lead to the enactment of the Federal Aid Highway Act of 1956 that authorized the construction of a national 41,000-mile Interstate Highway System.

Each state built their Beltway segments to the national Interstate highway standards that were current at that time, with generally similar design standards, and all of the 64-mile Beltway was built to full freeway standards (divided highway with at least two lanes each way, no at-grade crossings, and no adjacent direct land access), and it was built with six lanes (three each way) except for the four lane (two each way) 14.5 mile segment in Virginia between the northern Potomac River crossing and I-95 at Springfield. While the highway was in final design in the late 1950s, Virginia officials requested that BPR federal highway officials approve a six-lane design on the entire 22-mile Virginia section of the Beltway, but the BPR approved only four lanes on the above 14.5-mile segment, an action that by the late 1960s was seen by many people to have been a mistake due to the frequent peak period traffic congestion that had affected that segment by then, although it can be argued that when the final design had to be frozen in preparation for construction in the late 1950s, that the traffic projections justified no more than four lanes on that segment, given the modest level of residential and business development that existed at that time in Northern Virginia. The entire eastern portion of the Beltway east of I-95 was built with six lanes (three each way), so an ‘I-95 bypass’ section of the Beltway was built with six lanes from the outset.

The six-lane portion of the Beltway east of the I-95 junctions actually did have several 1/4-mile-long lane drops from three lanes to two: where I-295 merged into the Inner Loop immediately before the Wilson Bridge, where the Inner Loop outer lane became a collector-distributor (C-D) roadway at US-1 Jefferson Davis Highway, where the Inner Loop outer lane became a collector-distributor roadway at VA-241 Telegraph Road, and where the ramps from US-1 merged into the Outer Loop immediately before the Wilson Bridge. The two locations with C-D roadways at interchanges had the outer mainline lane exiting into a one-lane C-D roadway, intercepting the ramps and loops, and the C-D roadway continued on and rejoined the mainline of the Beltway as the outer lane, so in one respect there were three directional lanes at these locations. The two instances of lane drops immediately before the Wilson Bridge did see the three mainline lanes briefly drop to two lanes so that the ramp could merge in and become the outer lane. All of these locations had mainline widening that was completed in 1973 (at I-295 and US-1) and 1977 (at VA-241) to provide at least three mainline lanes each way without lane drops.

There is one place still existing where the mainline Beltway roadway has a lane drop from three lanes to two, for 1/4 mile on the Inner Loop where the two-lane roadway from southbound I-270 merges into the Inner Loop roadway of the Beltway near MD-355 Wisconsin Avenue.

Many of the original 38 Beltway interchanges were built with the cloverleaf design (four ramps and four loops), and some were a modified cloverleaf design that included one or more semi-directional (flyover) ramps. Each Interstate interchange (I-95 and I-66 in Virginia, I-95 and I-295 and both legs of I-270 in Maryland), was entirely or mostly a semi-directional interchange. A few of the Beltway interchanges were built with the diamond (four ramps) design.

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Final Design of Capital Beltway

Highway agencies and their hired engineering consultants in both Maryland and Virginia, charted a completely new alignment for the beltway, because so few inter-suburban roads existed in the mid-1950s that could have been upgraded to become part of the route. No Potomac River bridges existed in the Washington metropolitan area between Virginia and Maryland, so two completely new Potomac River bridges were required for building a new beltway which would completely encircle and bypass Washington and Arlington.

Micheal Baker Corporation was the main engineering firm that performed the final design on segments of the Capital Beltway in Maryland. Michael Baker by then was a nationally known engineering firm that had designed many highway and bridge projects. The Maryland State Roads Commission (SRC) selected Micheal Baker to design its portion of the Beltway, beginning with the conceptual alignments drawn in 1952 by the M-NCPC before the state had officially approved the project. The Pennsylvania-based firm opened a branch office on the third floor of the new College Park Business Center, in April 1954. The Baker office in College Park, Maryland, quickly obtained contracts for many highway projects, from the SRC, the District of Columbia Department of Highways, and the National Park Service. By 1957, according to an in-house newsletter, Baker had completed designs on many Maryland and D.C. projects, and the design projects underway at that time included 14 miles of the I-695 Baltimore Beltway, the 45-mile Northeastern Expressway (I-95 northeast of Baltimore), and 38 miles of roadway and 68 major structures (mainly bridges) on the Washington Circumferential Highway. The Maryland segment of the beltway was planned to follow open corridors as much as possible, to avoid heavily developed areas where possible, and in Prince Georges County it was possible to avoid heavily developed areas, but in Montgomery County that was not possible in every area as there were some segments with heavy impacts to developed areas with many homes and businesses acquired for the highway right-of-way; and a 2-mile beltway segment was built through Rock Creek Park over the objections of state and federal public park agencies, something that probably would not have been possible after Congressional enactment of the 1969 National Environmental Policy Act (NEPA), as one of the many things that NEPA did was to make it virtually impossible to build a highway through major public parkland. The alternative to the Rock Creek Park alignment would have been to locate the highway on a straighter alignment about a mile to the north, which would have been advantageous from a traffic engineering standpoint, but which was effectively politically impossible as it would have passed through heavily developed and very affluent residential sections of Bethesda. After NEPA, it is quite possible that it would not have been possible to find a feasible location build that segment of the Beltway if it had not already been built, and that would have left a missing link in the Beltway between MD-355 Wisconsin Avenue and MD-97 Georgia Avenue.

Howard, Needles, Tammen, and Bergendoff, today named HNTB Corporation, was the main engineering firm that performed the final design on segments of the Capital Beltway in Virginia. The New York-based firm, which had designed several major post-World War II turnpikes including the New Jersey Turnpike and the Maine Turnpike, was contracted by the Virginia Department of Highways (VDH) to plan the alignment of the entire 22 miles of Beltway in Virginia and to perform the final design of the Beltway between the Woodrow Wilson Bridge and US-50 Arlington Boulevard. VDH performed the final design in-house for the Beltway segment between US-50 and the northern Potomac River bridge. Howard, Needles, Tammen, and Bergendoff was contracted by VDH in 1956 to perform a location routing study for Virginia’s entire Interstate highway system, and regarding the Virginia portion of the Washington circumferential highway, they wrote that this highway would be “an entirely new facility, which neither supplements nor replaces any existing routes”, and that “It is notable that this line follows virtually the only open corridor through the area. To shift from this alignment would either involve considerable property damage to heavily developed areas or require the location of this route much further from Arlington and the Washington area.”
The U.S. Bureau of Public Roads (BPR) administered the design and construction of the 1.1-mile Potomac River bridge (Woodrow Wilson Memorial Bridge) at Alexandria, and contracted with Howard, Needles, Tammen, and Bergendoff, to perform the final design of the bridge.

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Naming of Capital Beltway

When the final link of the Beltway was completed and opened to traffic on Monday, August 17, 1964, it had already been officially named the Capital Beltway, and its route designation throughout was Interstate I-495. In the years after the proposed beltway route had officially made its first appearance on the 1950 planning maps of the National Capital Park and Planning Commission (NCPPC), and the 1952 planning maps of the Maryland - National Capital Planning Commission (M-NCPC), it had been referred to by a variety of names, including the Washington Circumferential Highway, Circumferential Highway, the circumferential, the belt road, the belt parkway, the inter-county freeway, the inter-county belt highway, the inter-county belt freeway, and the inter-county belt parkway. During the construction period of the Beltway, Maryland and Virginia officials separately made efforts to find a name which would be easy to speak and which would fit easily on roadway signs.
The Maryland State Roads Commission (SRC) first proposed the names "Colonial Beltway" and "Colonial Parkway" in March 1960, and then decided on the name "Capitol Beltway". Fairfax County, Virginia officials approved the name "Capital Ring", but state officials disagreed, as they wanted a name to honor George Washington or George Mason. Virginia officials then decided to name its Beltway section "Capitol Beltway", in agreement with Maryland officials. In the next few months, various officials and citizens pointed out that the word "capitol" refers to the building that houses the legislature (which is true for a state capital or for the U.S. capital), while the word "capital" refers to the entire capital city; so the proper word to name a highway that encircles Washington, D.C., would use "capital" and not "capitol", so on June 22, 1960 the highway was officially named "Capital Beltway" by both states, and that has been the official name since then.

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Naming and Construction of Capital Beltway Potomac River Bridges

The Capital Beltway crosses the Potomac River in two places, a southern crossing at Alexandria, Virginia, and a northern crossing near Cabin John, Maryland. Each crossing connects Virginia and Maryland, and a small mid-span section of the southern bridge crosses an over-water corner of the District of Columbia. The closest local road access interchanges on each crossing are, for the northern crossing, in Montgomery County, Maryland, and in Fairfax County, Virginia; and for the southern crossing, in the City of Alexandria, Virginia, and in Prince Georges County, Maryland. The Virginia approach of the southern crossing is in the City of Alexandria, as 2/3 mile of the Beltway is in the City of Alexandria and the rest of the 22-mile Virginia section of the Beltway is in Fairfax County.

The construction of the original 5,900 foot long southern Potomac River crossing at Alexandria was authorized by the U.S. Congress on August 30, 1954, to be built and 100% funded by the federal government. It was initially named the Jones Point Bridge, and was officially named the Woodrow Wilson Memorial Bridge, on May 22, 1956. Excerpts from "Why is the Woodrow Wilson Memorial Bridge Named after Woodrow Wilson?", by the Rambler, a historian of FHWA (Federal Highway Administration).

On August 30, 1954, President Dwight D. Eisenhower signed Public Law 83-704, "An Act to authorize and direct the construction of bridges over the Potomac River, and for other purposes." One provision stated:
The Secretary of the Interior . . . is authorized and directed to construct, maintain, and operate a six-lane bridge over the Potomac River, from a point at or near Jones Point, Virginia, across a certain portion of the District of Columbia, to a point in Maryland, together with bridge approaches on property owned by the United States in the State of Virginia.

The sum of $14,925,000 was authorized to be appropriated for the Jones Point Bridge. However, the cost of the approaches and improvements to collateral streets and highways was to be borne by the States of Maryland and Virginia:
On May 22, 1956, President Eisenhower signed Public Law 84-534, which transferred responsibility for the project to the Secretary of Commerce, whose Department included the Bureau of Public Roads (BPR). The same day, the President signed Public Law 84-535, which renamed the "Jones Point Bridge" the "Woodrow Wilson Memorial Bridge."

Construction began on the Woodrow Wilson Memorial Bridge in 1958. The six-lane Potomac River bridge and 3.2 miles of six-lane Beltway between US-1 Jefferson Davis Highway in Virginia and MD-210 Indian Head Highway in Maryland, opened to traffic on December 28, 1961. The bridge is most commonly publicly referred to by the shorthand name versions of Woodrow Wilson Bridge or Wilson Bridge.
The under construction new twin-span 12-lane Potomac River bridge for the I-95/I-495 Beltway at Alexandria, will have the same name as the original bridge, the Woodrow Wilson Memorial Bridge. The first new 6-lane Woodrow Wilson Bridge was opened to traffic in two stages in June and July of 2006, and it will be configured for 3 lanes each way until the 6-lane bridge for the Inner Loop of the Beltway opens to traffic in mid-2008. The original Woodrow Wilson Bridge was permanently closed to traffic on Saturday, July 15, 2006. When the new twin-span Woodrow Wilson Bridge is complete in mid-2008, it will then be jointly owned and administered by the states of Virginia and Maryland. An agreement was worked out in August 2001 by the Federal Highway Administration (FHWA), Virginia and Maryland, to turn over the ownership of the new bridge, when it is completed, to joint ownership by Virginia and Maryland.
The construction of the Beltway's 1,450-foot-long northern Potomac River crossing near Cabin John, Maryland, was administered by the Maryland State Roads Commission (SRC) as a conventional Interstate highway project. The six-lane Potomac River bridge, and 7.0 miles of Beltway approaches between VA-7 Leesburg Pike in Virginia and MD-190 River Road in Maryland, opened to traffic on December 31, 1962. While an impressive bridge in its own right, it is much shorter than the Woodrow Wilson Bridge, and the Woodrow Wilson Bridge crosses a major shipping channel, while the northern crossing does not pass over a navigation channel, as the Potomac River is a shallow rocky river at that point. This northern crossing Beltway bridge did not have an official name until 1969, but it was commonly referred to as the Cabin John Bridge, a name that was "borrowed" from a nearby 200-foot-span stone arch aqueduct bridge that was opened in 1863 over Cabin John Creek in Montgomery County, Maryland, and this local bridge is still an aqueduct as well as carrying 2 lanes of MacArthur Boulevard. The 50th anniversary of the nation's largest military veterans organization was the occasion for the expression of Maryland legislative sentiment to name the Beltway bridge the American Legion Memorial Bridge, effective May 30, 1969, on Memorial Day. The public was slow in utilizing the new name, and for many years afterward many local people still called it the "Cabin John Bridge", although by the 1990s, it was most commonly publicly referred to as the American Legion Memorial Bridge, or by the shorthand name versions of Legion Bridge or American Legion Bridge.

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Construction of Capital Beltway in Virginia

Construction of the 22-mile Virginia section of the Capital Beltway began three years after Maryland’s, in April 1958, on the segment between VA-236 Little River Turnpike and VA-617 Backlick Road. Construction moved forward within the next few years on the rest, and there were delays until 1963 on the segment between VA-7 Leesburg Pike and US-50 Arlington Boulevard due to difficulties in preparing the contact for a bridge overpass over the Beltway for the Washington & Old Dominion Railroad line. There were also difficulties in constructing the Beltway segment through marshlands along the stream valley of Cameron Run along the southern border of the City of Alexandria in the area where the Beltway has interchanges with US-1 Jefferson Davis Highway and VA-241 Telegraph Road.

The first 6.7 miles of I-495 in Virginia opened to traffic on December 16, 1961, the section between I-95 Shirley Highway and US-50 Arlington Boulevard. The 0.8 miles of I-495 in Virginia between US-1 Jefferson Davis Highway and the state line, along with the Woodrow Wilson Bridge and Maryland segment to MD-210 Indian Head Highway (the segment comprised 3.2 miles in both states), opened to traffic on December 28, 1961. On December 31, 1962, 4.7 miles of I-495 opened to traffic between the state line at the northern Potomac River bridge, and the VA-7 Leesburg Pike interchange, and this segment opening included the 2.3 miles in Maryland to the MD-190 River Road interchange. The 3.2 miles of I-495 between US-50 Arlington Boulevard and VA-7 Leesburg Pike opened to traffic on October 2, 1963. The last 6.7 miles of I-495 in Virginia, between I-95 Shirley Highway and US-1 Jefferson Davis Highway, opened to traffic on April 2, 1964.
In the April 2, 1964, final segment opening of the 22-mile Virginia section of the Capital Beltway, the opening ceremonies were held on the Beltway roadway 1/2 mile west of the I-495/US-1 interchange. It was another cold, wet and windy day, a seeming hallmark of Capital Beltway openings, and over 200 attendees listened to speeches by Virginia Department of Highways Commissioner (agency head) Douglas B. Fugate, U.S. Bureau of Public Roads Chief Rex Whitton, and Virginia Governor Albertis Harrison, and music by the 75th Army Band of Fort Belvoir. This segment opening also marked the completion of the first Interstate highway statewide in Virginia.
Most of the Capital Beltway was built in areas where the soil is dry enough and has a high enough content of clay and/or rock that in its natural state the soil provided a good base for building a highway. For the most part, the topography and soil geology of suburban Maryland and Northern Virginia was conducive to standard highway engineering and construction techniques. The Beltway is located in two geologic provinces, neither of which was particularly challenging to road builders. Much of the eastern half of the Beltway is in the Coastal Plain, which is a gently undulating plain that extends along the Eastern Seaboard from Mexico to New Jersey, and it is characterized by tidal estuaries such as rivers and bays including the Potomac River and Chesapeake Bay, and the terrain gradually rises in elevation from the Atlantic Ocean westward to hills up to about 400 feet above sea level in elevation near its western boundary. The geologic province immediately to the west is the Piedmont, which is a band of rolling hills with rocks just below the surface, running from Alabama to New York, and its elevations range from sea level to about 1,000 feet above sea level. The Piedmont is bounded to the west by the Triassic Lowland province. The boundary between the Coastal Plain and the Piedmont generally bisects the District of Columbia and the Capital Beltway from southwest to northeast. The topography and geology of both provinces posed relatively few challenges to the designers of the Beltway.
There were difficulties in constructing the six lane (three lanes each way) Beltway segment through marshlands along the stream valley of Cameron Run near the southern border of the City of Alexandria in the area where the Beltway has interchanges with US-1 Jefferson Davis Highway and VA-241 Telegraph Road. Like many stream valleys, the soil has a high amount of organic material and has a high water content, so the soil is compressible and in its natural state is inadequate for supporting a highway. The natural channel of Cameron Run meandered north and south of the Beltway right-of-way between VA-241 and US-1, and on the mid-section of that segment, the channel of Cameron Run was relocated to a straight channel alongside the south edge of the Beltway. On large parts of that Beltway segment, borrow excavation (select soil backfill) was deposited to provide the base of the Beltway roadways. Part of the ramps and roadways at the I-495/US-1 interchange were built on bridge structure over marshlands and open water.

The above design, like building the 2-mile Beltway segment through Rock Creek Park in Montgomery County, Maryland, most likely would have been impossible to build after enactment of the 1969 National Environmental Policy Act (NEPA), with its stringent federal environmental standards. Unfortunately, these kind of highway designs were commonplace all over the U.S. before NEPA, as the rationale was that it enabled urban and suburban highway segments to be built in places that did not displace houses and businesses; engineers and planners routinely routed highways through areas which would provide the least resistance, and in practical terms that often meant sites that were occupied by minorities or the poor, or riverfronts or stream valleys or parks that housed few or no residents or business owners to complain. After NEPA, many such highway segments were able to be built without filling in marshlands and streams, but only by placing the highway on bridge structures that passed over those natural resources, even though financially that made the highway segment much more expensive to build than if it was built on earthen fill. Such a post-NEPA design would have placed most of the 1.3 miles of Beltway between VA-241 and US-1 on bridge structure, from about 1/4 mile east of VA-241 to 1/4 mile east of US-1, plus nearly all of the I-495/US-1 interchange; and the stream channel of Cameron Run would have been left in its natural place.

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Pavement Types on Capital Beltway

Asphalt concrete, commonly known simply as asphalt, also sometimes called blacktop or hot-mix asphalt, is a composite material commonly used for construction of highway pavement and parking lots. It consists of a liquid asphalt binder and mineral aggregate (generally gravel plus sand) mixed together at about 300 degrees Fahrenheit (about 150 degrees Celsius) then laid down in layers and compacted.

Concrete is a construction material that consists of cement (commonly Portland cement), aggregate (generally gravel plus sand), water, and admixtures. Concrete solidifies and hardens after mixing and placement, due to a chemical process known as hydration. The water reacts with the cement, which bonds the other components together, creating a stone-like material. Portland cement concrete is also called hydraulic cement concrete. The concrete utilized on highway roadways and bridges, is reinforced internally with a grid of steel bars, and the term ‘reinforced concrete’ refers to concrete that is reinforced (given additional strength) in this manner.

Today the entire Beltway mainline roadway (excepting some bridges) has a riding surface of asphalt concrete. The bridges in the Beltway mainline all have a roadway deck constructed of reinforced Portland cement concrete, and on many of them that is the vehicle riding surface, although some of them have an asphalt concrete surface layer that is the riding surface. The current Woodrow Wilson Bridge and American Legion Bridge have a riding surface of reinforced Portland cement concrete.

Along most of the length of the Beltway, there is an original reinforced Portland cement concrete pavement underneath the asphalt concrete surface, and that original concrete pavement has a slab thickness of 8 to 9 inches, depending on the section, and that was the original riding surface; and after several decades of wear it was overlaid with asphalt concrete. When overlaid, the Portland cement concrete pavement was repaired first to fix the damaged sections, and then several layers of asphalt concrete totaling at least 5 to 6 inches in depth was placed on top of the Portland cement concrete pavement, resulting in a strong smooth pavement structure.

The original Virginia Beltway pavement types are as follows. The 21-mile Virginia section of the Beltway between the American Legion Bridge and VA-241 Telegraph Road, had reinforced Portland cement concrete pavement. When it was widened to eight lanes (four each way) 1974-1977, the reinforced Portland cement concrete pavement was widened the necessary width for the new traffic lanes, the shoulders were underlaid with 6 inch depth plain Portland cement concrete, and the entire roadway and shoulders were overlaid with a 6 inch depth asphalt concrete riding surface (per review of construction plans by Roads to the Future author and observation during construction). The 1.3 mile Virginia section of the Beltway between VA-241 Telegraph Road and the Woodrow Wilson Bridge was originally constructed with asphalt concrete, due to the fact that the segment was built on earthen embankment fill through a stream valley and marshlands, and the principle was that would be a better design to handle any settling of the roadway by adding a few inches depth of asphalt concrete overlay in a section that settled.
The original Maryland Beltway pavement types are as follows. The 31-mile Maryland section of the Beltway between the Woodrow Wilson Bridge and MD-97 Georgia Avenue, originally had reinforced Portland cement concrete pavement, and when the 29-mile section between MD-210 Indian Head Highway and MD-97 Georgia Avenue was widened from six lanes (three each way) to eight lanes (four each way) in 1970-1972, one reinforced Portland cement concrete lane each way was added on the inside of each directional Beltway roadway. This section of the Beltway was overlaid with asphalt concrete with at least 5 to 6 inches in depth, in the 1980s. The 10-mile Maryland section of the Beltway between MD-97 Georgia Avenue and the American Legion Bridge, originally had asphalt concrete pavement, and the later widening projects utilized the same paving material. The shoulders on the Maryland section of the Beltway have always utilized asphalt concrete throughout.

The various connecting roads and highways that interchange with the Beltway, had the interchanges and connecting roads built along with the Beltway. The ramps typically were constructed with the same pavement material as that section of the mainline Beltway. The connecting roads and highways were in most cases constructed with asphalt pavement.

The current Woodrow Wilson Bridge Project (2000-2011) includes the widening of 7.5 miles of the Beltway to 10 to 12 lanes, between west of VA-241 Telegraph Road and east of MD-210 Indian Head Highway, and the all land roadways and ramps in this segment will be completely replaced with new roadways and ramps, and the land roadway paving material will be full-depth asphalt concrete pavement, throughout the project. All bridges on the project will be replaced with new bridges, and the riding surface of the roadway decks will be reinforced Portland cement concrete.

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Completion of Capital Beltway

The final link of the Capital Beltway, in Montgomery County and Prince Georges County, Maryland, was completed and opened to traffic on Monday, August 17, 1964, the 24.7-mile section between MD-355 Wisconsin Avenue and MD-4 Pennsylvania Avenue Extended.

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Route Numbering of Capital Beltway

Following the Federal Aid Highway Act of 1956 by Congress that authorized the construction of the national 41,000-mile Interstate Highway System, including the proposed 64-mile-long Washington circumferential highway, the entire beltway was granted the Interstate Route I-495 designation by federal and state highway officials.

Three-digit Interstate routes have a leading digit with the last two digits being the mainline route that it supplements, so I-x95 routes would have routes such as the ones in Virginia, I-195, I-295, I-395 and I-495. An odd-number leading digit signifies a spur route off a mainline route (examples are I-195 and I-395). An even-number leading digit signifies a loop around a city (examples are I-295 and I-495), or a branch route connecting two Interstate highways (an example is I-270 in Maryland). Three-digit Interstate route numbers can duplicate, but not in the same state.

The completed Beltway was designated I-495 throughout from 1964 to 1977. In 1977, the eastern portion became I-95, and Shirley Highway inside the Beltway was changed from I-95 to I-395. This was done because of the cancellation of proposed I-95 from New York Avenue in the District of Columbia northward into Prince George's County, Maryland, to I-495. The I-95 designation was moved to the eastern half of the I-495 Beltway in 1977, and I-495 was removed from the eastern half of the Beltway, and I-395 replaced the I-95 designation on Shirley Highway from I-495 to the 14th Street Bridge, on the 14th Street Bridge itself, on the Southwest Freeway in D.C. and on the Center Leg Freeway in D.C. Today's I-395 is the former segment of I-95 inside of the Beltway.
Many regional motorists never fully adjusted to having a full-circle beltway with halves with two different numbers (I-95 and I-495). In 1991, the I-495 designation was applied back to the eastern portion of the beltway, so the whole Beltway is again I-495, and the eastern portion is I-95 also (it carries both I-95 and I-495). The Beltway has the clockwise direction (as in looking at a map of the Beltway) signed as the Inner Loop, and the counter-clockwise direction is signed as the Outer Loop.

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Exit Numbering on Capital Beltway

The exit (interchange) numbering on the Beltway began with a sequential system in 1964 when the Beltway was fully complete, and it was a somewhat hybrid system from 1980 to 2000, and in 2000 was finalized to a fully milepost-based system that should last permanently. The original exit numbering system was sequential numbering from 1 to 38 (there were no “number gaps” except for future Exit 22 that later was canceled), starting at Exit 1 at US-1 in Alexandria, running clockwise as viewed on a map from above, advancing around the south, west, north and east of Washington, ending at Exit 38 at I-295 near the Wilson Bridge.

The official decision in 1977 to cancel the remaining unbuilt segments of I-95 in the District of Columbia and Maryland, and the concurrent decision to move the I-95 designation to the eastern portion of the Beltway, was the cause of the need to renumber the exits on the Beltway.
The period of the 1980s and later was also a time when many states changed their Interstate highway exit numbering from sequential numbering to milepost-based numbering. Sequential exit numbering means that the exit numbers increase consecutively (1, 2, 3, 4, etc., in sequence) one by one along the highway. Milepost-based exit numbering means that each exit number is the same as the number of the nearest milepost, and while the numbers are not consecutive (for example if four exits in sequence were at mileposts 7, 9, 11 and 15, then those would be the respective exit numbers), milepost-based exit numbering has widespread public support because it makes it easy to compute how many miles one needs to travel from where they are currently, to reach their destination exit, although the fact that exit numbers usually start over at zero at the beginning of each state border, removes that advantage for an inter-state trip.

Maryland began instituting milepost-based exit numbering on its Interstate highways about 1980, and specifically on the Capital Beltway in 1980. The federal standard for exit numbering on Interstate highways, is for the numbering to advance from south to north on north-south highways, and from west to east on east-west highways. Since the eastern portion of the Beltway was I-95 alone at that point, Maryland posted milepost zero at the state border at Alexandria, and advanced the milepost numbers along I-95 all the way to Delaware. At the I-95/I-495 junction north of Washington at Milepost 27, Maryland continued that same increasing milepost sequence from 27 to 42 along the I-495 Beltway all the way to the Virginia shoreline at the Legion Bridge near Cabin John, Maryland. Each Beltway interchange in Maryland was given milepost-based exit numbering, so from 1980 and onward there were exits 2 through 41 in Maryland, running counterclockwise as viewed on a map from above. This is opposite of the Beltway’s original clockwise exit numbering system. Virginia’s Beltway exits remained in the original system of running clockwise sequentially from 1 to 14, so the two states had their exit numbers advancing in the opposite direction, and each state had a Beltway exit for the numbers 2, 3, 4, 7, 9, and 11. Maryland’s Beltway exit numbering system has not changed since 1980.

In 1981, Virginia renumbered its exits 1 through 4 to 58 through 61 to be consistent with the rest of its sequential exit numbering on its I-95, and while this eliminated the duplication of Beltway exit numbers 2, 3 and 4 in both states, it created three unrelated exit numbering schemes on the Beltway. A 1981 Washington Post editorial called this an “atrocity,” that resulted in “two unrelated sets of Virginia Beltway exit numbers, going in opposite directions,” and “two unrelated sets of exit numbers (between Maryland and Virginia), going in opposite directions.” A couple years later Virginia reverted those exit numbers back to 1 through 4 to reduce the Beltway exit numbering schemes back to two.

In 1991, the two states decided to apply I-495 back to the I-95 eastern portion of the Beltway. In 1987, the two states agreed to post along the Beltway signs with a Capital Beltway logo in red, white and blue, with an image of the U.S. Capitol building surrounded by a circle, and the Beltway terms “Inner Loop” and “Outer Loop” came into use then, “Inner Loop” for the clockwise-running roadway, and “Outer Loop” for the counterclockwise-running roadway. Looking at the Beltway on a map from above, the loop of the clockwise-running roadway is inside of the loop of the counterclockwise-running roadway, hence the terms “inner” and “outer” for the concentric roadways of the Beltway.

Virginia did not convert its statewide Interstate highway exit numbering system from sequential numbering to milepost-based numbering until beginning in 1992, and the Beltway exits were renumbered in 2000. At that time it was decided to continue Maryland’s I-495 mileposting from Maryland’s Milepost 42 at the Virginia shoreline at the Legion Bridge near Cabin John, to a new Milepost 57 at the I-95/I-395/I-495 Springfield Interchange; and to continue I-95’s mileposting (170 through 177) along the I-95/I-495 section of the Beltway from I-95/I-395/I-495 Springfield Interchange to the state border at the Wilson Bridge at Alexandria.

When exit numbers were changed in these various renumberings, new exit number signs were installed, and each exit changed would carry an “Old Exit nn” sign for a year after the change, to assist motorists in adjusting to the change.

The current Beltway exit numbering system should be permanent, as it follows the milepost-based Interstate highway exit numbering system in both states, which should be permanent. There is no foreseeable reason why the Beltway exit numbering system should see any more changes (the future completion of the canceled original downtown route of I-95 through the District of Columbia is not impossible but is highly unlikely). It is a shame that it took from 1980 to 2000 to fully change the Beltway’s original sequential exit numbering system based on I-495 alone, to the current milepost-based exit numbering system based on I-495 and its eastern I-95 overlap. This underscores the inadequate Beltway coordination between the two states, at times, that has impacted the management of what is one metropolitan circumferential freeway. It could be argued that Virginia was remiss for not immediately following Maryland’s 1980 change in its Beltway exit numbering system, by installing the same system on its portion of the Beltway, but it could also be argued that Maryland was presumptuous for imposing milepost-based exit numbering on its section of the Beltway at a time when Virginia was not interested in imposing milepost-based exit numbering on its Interstate highways (and wasn’t until starting 12 years later, which was Virginia’s prerogative).
The Capital Beltway when completed in 1964 had 37 interchanges, and in 1971 that number increased to 38 when I-95 in Maryland was completed to the Beltway. These two pairs of Beltway junctions were each defined as a single interchange in the original exit numbering system -- I-70S and MD-355, and MD-190 and Cabin John Parkway; and in Maryland's exit renumbering, each in those pairs has a separate exit number; and it is a matter of definition as to whether each of those pairs should be considered to be one interchange or two interchanges. The 4 interchanges marked in the table below as "n/a" for Original Number, did not exist when the Beltway was completed in 1964, were not planned at that time, and were all constructed after 1990. The Beltway as exit-numbered in 2007 has 44 interchanges.

CURRENT # / Exit Name / PREVIOUS #

2 Interstate 295 Anacostia Freeway / (future) National Harbor 38
3 MD-210 Indian Head Highway 37
4 MD-414 Saint Barnabas Road 37A
7 MD-5 Branch Avenue 36
9 MD-337 Allentown Road / Andrews Air Force Base 35
11 MD-4 Pennsylvania Avenue 34
13 Ritchie-Marlboro Road (n/a)
15 MD-214 Central Avenue 33
16 Arena Drive / FedEx Field (n/a)
17 MD-202 Landover Road 32
19 US-50 John Hanson Highway 31
20 MD-450 Annapolis Road (original name was Defense Highway) 30
22 Baltimore-Washington Parkway 29
23 MD-201 Kenilworth Avenue 28
24 Metrorail Greenbelt Station (n/a)
25 US-1 Baltimore-Washington Boulevard 27
27 Interstate 95 26
28 MD-650 New Hampshire Avenue 25
29 MD-193 University Boulevard 24
30 US-29 Colesville Road 23
- Northern Parkway (unbuilt) 22
31 MD-97 Georgia Avenue 21
33 MD-185 Connecticut Avenue 20
34 MD-355 Wisconsin Avenue / Rockville Pike 19
35 Interstate 270 (originally was I-70S) 19
36 MD-187 Old Georgetown Road 18
38 Interstate 270 Spur (originally was I-270) 17
39 MD-190 River Road 16
40 Cabin John Parkway 16
41 Clara Barton Parkway (originally MD's George Washington Memorial Parkway) 15
43 George Washington Memorial Parkway 14
44 VA-193 Georgetown Pike 13
45 Dulles Airport Access Road and VA-267 Dulles Toll Road 12
46 VA-123 Chain Bridge Road 11
47 VA-7 Leesburg Pike 10
49 Interstate 66 9
50 US-50 Arlington Boulevard 8
51 VA-650 Gallows Road 7
52 VA-236 Little River Turnpike 6
54 VA-620 Braddock Road 5
57 Interstates 95 and 395 - Shirley Highway 4
173 VA-613 Van Dorn Street 3
174 Eisenhower Avenue Connector (n/a)
176 VA-241 Telegraph Road 2
177 US-1 Jefferson Davis Highway 1

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Speed Limits on Capital Beltway

Since the 1973 National Maximum Speed Limit act was enacted, which mandated a maximum speed limit in the U.S. of 55 miles per hour, no segment of the Capital Beltway has had a higher speed limit than 55 mph. In 1987 the NMSL was modified to allow 65 mph on rural Interstate highways, and the Beltway was ruled to be in a metropolitan area (and not rural) and still subject to a federal maximum of 55 mph. In 1995 the U.S. Congress abolished the national maximum speed limit, and returned the setting of speed limits back to state control as was the case before 1973, thus making it possible to have higher speed limits on the Beltway.
The I-495 Capital Beltway opened in 1964 to much optimism and enthusiasm. By 1968 and 1969, traffic volumes of cars and trucks had grown to the point where the highway was always well-used, with traffic volumes during peak hours approaching the capacity of the highway on various sections, and the maximum segment volume then was about 80,000 vehicles per day.

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Capital Beltway Operation

Today much of the Beltway carries over 200,000 vehicles per day, and even with major widening projects between 1972 and 1992, making nearly the entire Beltway eight lanes wide (four each way), much of the Beltway experiences major congestion for major periods of each day.

Wiki Capital Beltway Page

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"HOT" Lanes Contruction Information

HOT lanes are tolled lanes that operate alongside existing highway lanes to provide users with a faster and more reliable travel option. Buses, carpools (HOV-3), motorcycles and emergency vehicles will have free access to HOT lanes. Drivers with fewer than three occupants can choose to pay to access the lanes.Tolls for the HOT lanes will change according to traffic conditions to regulate demand for the lanes and keep them congestion free - even during peak hours.

The I-495 Virginia HOT Lanes Project will deliver the most significant enhancements to the Beltway since its opening in 1964. The project includes two new lanes in each direction from the Springfield Interchange to just north of the Dulles Toll Road and the replacement of more than $260 million in aging infrastructure. This includes replacing more than 50 bridges, overpasses, and major interchanges.

Here are some links to past articles about "HOT" lanes from your Leewood Times & Leewood.us

VDOT Holds Meetings about HOT lanes on Interstate 95 & 395

NEW Hot Lanes on I-495

Dulles Metrorail in on Track and Underway

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Telegraph Road Construction Project

Telegraph Rd. Interchange final component of $2.5B Wilson Bridge Project

Highway construction crews are out in force for several years of work to upgrade the Telegraph Road interchange at the beltway, the final major contract of the Woodrow Wilson Bridge Project.

The $236 million effort to reconstruct the interchange may take drivers a while to get used to the lane shift. Outer loop traffic now begins merging from four lanes down to three lanes about a mile sooner that it used to, at the Eisenhower Avenue connector exit instead of Telegraph Road.

The Commonwealth Transportation Board awarded a $236.4-million contract to rebuild the I-95 interchange at Telegraph Road. Construction will take five years to complete. Building an improved Telegraph Road Interchange is the final component of the overall $2.52-billion Woodrow Wilson Bridge Project. Overall, the contract will build 11 ramps and bridges, five box culvert extensions, drainage improvements, retaining walls, noise walls, pedestrian paths, traffic systems, lighting, signage, landscaping and an environmental mitigation project at the Cameron Run Wetlands.

The Telegraph Road Interchange project involves the complete reconstruction of the existing interchange to include ramp improvements, bridge widening/lengthening and widening of the I-95/I-495 mainline roadway section from 2.08 miles west of Telegraph Road to 0.5 miles to the east. Improvements along Telegraph Road will include roadway reconstruction, bridge reconstruction, intersection improvements and utility relocations from Duke Street on the north to Lenore Lane to the south.

During construction the Telegraph Road Interchange project will be closely coordinated with several additional mega-projects in Northern Virginia, including the building of high-occupancy-toll lanes on I-95 and I-495 and widening I-95. Business and utility relocations as well as ground strengthening work were completed in advance of the interchange reconstruction.

The work is being carried out by Corman-Kiewit Constructors, a joint venture of Corman Construction and Kiewit Corp.

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Beltway TRAFFIC links

VDOT Traffic Cameras with Interactive Map

The above link is a great resource for you to use before you hit the roads.

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Dulles Metro Project

The Federal Transit Administration has approved the Metropolitan Washington Airports Authority to advance the Dulles Corridor Metrorail Project extension from East Falls Church to Wiehle Avenue into Final Design. The FTA said the project now meets the "threshold for entry into Final Design" and outlines the process for obtaining a Full Funding Grant Agreement.

The $159 million in federal funds which has been released for the project can be used for:

Right-of-way acquisitions
Reimbursement of third party preliminary engineering costs
Continuing with utility relocations
Final Design Work
Project administration
Maintenance of traffic efforts
Engineering and design of rail cars

Use the above link for more information about the Dulles Metro Project.


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Help sometimes comes at a price or with a hidden agenda, but our helpful guides have neither. We hope that the information in our Leewood Times Guides give you starting points and focus. Our goal is to assist you in making informed decisions.

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345 Money Saving Tips

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Leewood Times 2008 Winter Guide

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Leewood Times Energy Saving Tips Winter / Summer

Leewood Times Guide to Credit Repair

Leewood Times Guide to Fall Festivals

Leewood Times Guide to Going Green

Leewood Times Guide to Holiday Entertaining

Leewood Times Guide to Local Farmers Markets

Leewood Times Guide to New Years Resolutions

Leewood Times Guide to Seasonal Allergies & Pollen

Leewood Times Guide to Spring Cleaning

Leewood Times Guide to the Capital Beltway

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