List of gaps in Interstate Highways

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For the most part, the United States Interstate Highway System is a connected system, with most roads completed. However, some Interstates have gaps. There are several cases covered here:

• True gaps, where two sections of road are intended to be part of the same Interstate, but the two sections are not physically connected, or are only connected by non-Interstates, or are connected but the connection is not signed as part of the highway
• Freeway gaps, where the Interstate is signed as a continuous route, but part or all of it is not up to freeway standards; this includes drawbridges, where traffic on the Interstate can be stopped by boats
• Connection gaps, where a three-digit Interstate does not connect to its two-digit parent via a freeway-standard connection.

Not covered here are a few other cases worth mentioning:

• Gaps in Interstate Highway standards, such as shoulder widths and bridge clearances, since these are too frequent
• Two-digit Interstate numbers which are meant to be repeated, one on each side of the country, namely I-76, I-84, I-86 and I-88
• Gaps on the Interstates in Alaska and Puerto Rico, since those are not held to the same standards
• Places where Interstates cross but don't connect via a freeway-standard connection (e.g. I-84 and I-87).
• Places where a three-digit Interstate connects to its parent via another three-digit Interstate of the same parent; the numbering system allows for this
• Sometimes, near toll booths (e.g. Mackinac Bridge toll booth), a brief segment of the Interstate will have a median break with a double-yellow line but have at least 4 lanes total (i.e. Super-4).
• Median breaks for maintenance and/or emergency vehicles to access government driveways. These exist on many highways that are otherwise considered freeways, including Interstates.

Contents 1 True gaps 2 Freeway gaps 2.1 At-grade intersections and traffic lights 2.2 Undivided freeways 2.3 Drawbridges 3 Connection gaps 4 Sources

True gaps

• I-39 had a gap between Rockford, Illinois and Portage, Wisconsin until the late 1990s, when signage was added along I-90 to fill the gap.
• I-74 currently has three sections, one heading west from Cincinnati, Ohio, one from the Virginia/North Carolina state line along I-77 south and east to a point southeast of Mount Airy, North Carolina, and one concurrent with the only section of I-73, from Emery, North Carolina to Ulah, North Carolina. Other sections up to freeway standards are signed with I-74 shields that have FUTURE instead of INTERSTATE. Future I-73 shields are also placed along some of these sections, but only one section of I-73 is signed with normal Interstate shields.
• I-90. Many believe that there is presently a gap in I-90 at the Chicago Skyway, but there is controversy and confusion surrounding this issue. Historically the skyway was commonly considered to be, and was signed as, part of I-90. However, around 1999 the City of Chicago, Illinois determined it may never have applied for approval to sign it as an Interstate. (It also is not designed to Interstate standards.) The city resigned the skyway, and it is now mostly posted with "TO I-90" signs, with a few older signs remaining. Because of this development, it has been widely circulated, especially among road buffs, that there is now a gap in I-90. However, the Illinois Department of Transportation has always and continues to report the skyway as part of the Interstate system, and the Federal Highway Administration still considers it as such. A FHWA legal memo says "There is no doubt about it. The Chicago Skyway is officially part of I-90 that (has) always been included in the Dwight D. Eisenhower National System of Interstate and Defense Highways." [1][2]
• I-93 historically has had a gap through Franconia Notch State Park in northern New Hampshire. The road filling the gap, a section of US 3, is built to freeway standards but has only one lane in each direction to avoid adversely impacting the Old Man of the Mountain; such a road is known as a Super-2. Around 2002, the road, which had been signed as US 3 TO I-93, was resigned as a concurrency of I-93 and US 3. Exit numbers, which had been discontinuous with I-93, were renumbered to fit the rest of I-93. Thus this gap may be no more.
• I-95. Probably the most well known and significant of the Interstate gaps, I-95 is discontinuous near Trenton, New Jersey. Coming north from Philadelphia, Pennsylvania, I-95 loops around the north side of Trenton and ends at U.S. Route 1, where it becomes I-295, which heads back south. The other section of I-95 begins on the Pennsylvania Turnpike at the Pennsylvania/New Jersey state line, and heads north along the New Jersey Turnpike. Originally I-95 was planned have left the alignment north of Trenton and headed northeast to I-287 and run east along I-287 to the Turnpike, but this "Somerset Freeway" was never built. Extensions over the years have taken I-95 several miles further north to the US 1 interchange northeast of Trenton, and south along the New Jersey Turnpike to the Pennsylvania state line. Eventually an interchange will be built connecting the southern alignment with the Pennsylvania Turnpike, and I-95 will be rerouted via it, with the part north of that interchange becoming an extension of I-295.
• I-265 The Indiana portion of I-265 does not yet connect with the Kentucky portion of I-265 at either intended crossing of the Ohio River to form a future beltway around metropolitan Louisville, Kentucky. Funding to complete these two bridges and adjoining freeway has not yet been allocated. Additionally, the exact routing has not yet been finalized, as there are two possible connection points - one with I-265 in Kentucky, and one with I-264 in Kentucky, which would necessitate a change in the numbering of the Indiana Portion of the highway.

Freeway gaps

At-grade intersections and traffic lights

• Several Interstates in the southwest U.S. have at-grade intersections (including median breaks) with minor farm access roads. This is usually due to the lack of an old highway, and the need to provide access to property that was accessed via the road before it was upgraded to an Interstate. For instance, I-40 in both the western Texas Panhandle and western North Carolina has several driveways coming directly onto the road.
• I-70 uses part of US 30 along a surface road in Breezewood, Pennsylvania to get between the freeway heading south to Hancock, Maryland and the ramp to the Pennsylvania Turnpike. This is probably the most well known instance of traffic lights on an interstate. There used to be a sign of a policeman pointing at drivers leaving the Pennsylvania Turnpike to enter US 30, saying, "You! Slow Down!" Local businesses have lobbied to keep the gap to avoid loss of business. Map Aerial photo Photos of Eastbound I-70 with traffic lights: [3] [4] from [5]
• I-78 travels along a one-way pair of surface streets, 12th Street and 14th Street, in Jersey City, New Jersey, between the end of the New Jersey Turnpike Newark Bay Extension and the Holland Tunnel which leads into New York, New York. Along with the aforementioned I-70, this is the only other primary interstate with traffic lights (which exist on both the ends of the tunnel. Map and Aerial photo Photos of traffic lights in I-78: Eastbound I-78 in Jersey City, Westbound I-78 in New York City from [6]
• I-180 in Cheyenne, Wyoming has no parts built to freeway standards; in fact the interchange with I-80 is even a simple diamond interchange with two traffic lights on I-180, however it is expressway-quality with a few grade-separations. Map Aerial photo
• I-585 is cosigned with US 176, in which I-585 shields are present in beyond the point where it ceases to be a freeway, having passed through traffic lights. There also exists a sign that marks the road there as "I-585 Business Spur" and hence it is unclear whether that surface section of US 176 also belongs to I-585.
• I-676 has a surface street section at the west end of the Ben Franklin Bridge in Philadelphia, Pennsylvania because of historically significant areas. Signage and the Federal Highway Administration consider I-676 to use the surface streets, but the Pennsylvania Department of Transportation may consider I-676 to stay on the freeway to end at I-95, with the surface streets and the bridge being only US 30, and the part in New Jersey being a different I-676. Aerial photo
• I-690 in Syracuse, New York has a traffic light for one or two weeks each year, for buses to carry Great New York State Fair attendees from parking areas across the road to the fair.

Undivided freeways

This section talks about Super-2s and other undivided freeway sections of the Interstate.

• I-93 is undivided through Franconia Notch State Park in northern New Hampshire. Used to be a true gap and is now a substandard portion of Interstate freeway.
• The Thousand Islands Bridge of Interstate 81 is also undivided.

Drawbridges

• I-5 crosses the Columbia River from Portland, Oregon to Vancouver, Washington on the Interstate Bridge, a drawbridge. The Washington State Senate Transportation Committee is currently considering replacing this bridge.
• I-64/Hampton Roads Beltway crosses the South Branch of the Elizabeth River in Chesapeake, Virginia on the High Rise Bridge, a drawbridge.
• I-75 used to cross the Saginaw River in Saginaw, Michigan on the Zilwaukee Bridge, a drawbridge, but a new higher bridge was built.
• I-90 had a floating drawbridge (Lacey V. Murrow Memorial Bridge) over Lake Washington between Seattle and Mercer Island until a new span was installed in 1993.
• I-95 had a drawbridge over the St. Johns River in Jacksonville, Florida (Fuller Warren Bridge) until a new bridge was finished in 2002.
• I-95/I-495/Capital Beltway passes over the Potomac River on the Woodrow Wilson Bridge, a drawbridge, south of Washington, DC. A new higher bridge is being built, but it will still open for tall ships.
• I-95 had a drawbridge across the Hutchinson River in New York, New York until 1996.
• I-110 has a drawbridge across the Back Bay of Biloxi in Biloxi, Mississippi.
• I-264 has a drawbridge (Berkley Bridge) over the Elizabeth River in Norfolk, Virginia.
• I-278 has a drawbridge across the Bronx River in New York, New York.
• I-280 has a drawbridge (Stickel Memorial Bridge) over the Passaic River connecting Newark, New Jersey to Harrison, New Jersey.
• I-280 has a drawbridge (Craig Memorial Bridge) over the Maumee River in Toledo, Ohio; a non-drawbridge replacement will be finished in 2006.
• I-395 passes over the Potomac River on the 14th Street Bridge in Washington, DC, which used to be a drawbridge but is now inoperative (adjacent fixed spans constructed in the years leading up to the draw span's decommissioning have a clearance of 18 feet, so permanently shutting the draw span was no particular loss).
• I-695/Baltimore Beltway has a drawbridge over Curtis Creek south of Baltimore, Maryland, a bit to the west of the Francis Scott Key Bridge.

Connection gaps

• I-176 didn't connect directly to I-76 at Morgantown, Pennsylvania until 1996.
• I-238 in San Francisco, in spite of being a three-digit Interstate, does not correspond to an I-38, per normal numbering rules. Indeed, I-38 does not exist, and I-238 actually intersects two spurs of I-80. I-238 was named after CA-238, because there were eight I-80 spurs in California already at the time, and a CA-180 (California does not like to use the same number twice, even for different designation shields). Since then, I-480 has been demolished and its number is now free. Theoretically, I-238 could become I-480 and become in line with standards.
• I-384 didn't connect directly to I-84 at Hartford, Connecticut until 1987.
• I-585 used to connect with I-85 in Spartanburg, South Carolina, but I-85 was moved to a bypass and now I-585 ends at an I-85 Business loop. The signed connection to I-85 is via a surface section of US 176.
• I-587 in Kingston, New York connects with I-87 via a roundabout. There are no traffic lights or other cross traffic in the connection, and so it is debated whether this actually counts as a gap.

• The Long Island Expressway I-495 does not connect with Interstate 95. It was planned to connect to Interstate 495 in New Jersey through midtown Manhattan and again with Interstate 95 in Connecticut via a possible bridge/tunnel combination across the Long Island Sound. This portion was never built, and the New Jersey portion was downgraded to NJ 495. I-495 begins at the Queens-Midtown Tunnel and runs out Long Island toward Riverhead.

• The following Interstates connect to their parents only via Interstates of a different parent; it is allowed for this connection to be via a same-parented Interstate (like I-280 in California being connected to I-80 via I-680).
  • I-210 in California at present does not directly connect to I-10, though it used to (via what is now CA 57) and will again by 2008 when the last segment of CA 210 is finished and renamed to I-210.
  • None of the spurs of I-78 (I-278, I-478, I-678, I-878) connects to its parent. I-78 was planned to extend through New York City and end as two branches, where I-295 and I-695 now end at I-95. I-478 comes the closest, and would have intersected if the Westway project wasn't canceled; I-278, the only I-78 spur to leave New York City, was planned to extend northwest to I-78 at NJ 24. Since all the spurs are interconnected, only one of them needs to be eventually connected to its parent route to conform to standards.

Template:Ed rightMain Interstate Highways (major in pink)														Image:I-blank.svg
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89	90	91	93	94	95	96	97	99	(238)		H-1	H-2	H-3
Unsigned			A-1	A-2	A-3	A-4	PRI-1		PRI-2		PRI-3
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Sources

• misc.transport.road FAQ