List of gaps in Interstate Highways

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 meant to be part of the same Interstate, but signage indicates otherwise
• 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
• 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).

Contents

1 True gaps 2 Freeway gaps 2.1 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 along I-77 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 was removed from the Chicago Skyway around 1999, when the City of Chicago, Illinois realized that it had never gotten approval to sign it as an Interstate. The road is now posted with TO I-90 signs. However, the Federal Highway Administration may still consider it to be part of I-90.[1] (http://wwwcf.fhwa.dot.gov/programadmin/toll_Rds.html)
• I-93 has 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 is discontinuous near Trenton, New Jersey. Coming from Philadelphia, Pennsylvania, I-95 loops around the north side of Trenton and ends at US 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 would have left the alignment north of Trenton and headed northeast to I-287 and run east along I-287 to the Turnpike, but the 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.

Freeway gaps

• 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.
• 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. Local businesses have lobbied to keep the gap to avoid loss of business.
• 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.
• 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.
• 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.
• Interstate 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.

Drawbridges

• I-5 crosses the Columbia River from Portland, Oregon to Vancouver, Washington on the Interstate Bridge, a drawbridge.
• I-64/Hampton Roads Beltway crosses the South Branch of the Elizabeth River in Chesapeake, Virginia on 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-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 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.
• 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-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 Business Loop I-85. The signed connection to I-85 is via a surface section of US 176. Additionally, some I-585 shields are present at the other end after the road has passed traffic lights, but these may be posted in error, since some signs mark the road there as Business Spur I-585.
• 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 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 was planned to extend northwest to I-78 at NJ 24.

Template:Ed divPrimary Interstate Highways							Missing image Interstate_blank.png Interstate Highway marker
4	5	8	10	12	15	16	17
19	20	22	24	25	26	27	29
30	35	37	39	40	43	44	45
49	55	57	59	64	65	66	68
69	70	71	72	73	74	75	76 (W)
76 (E)	77	78	79	80	81	82	83
84 (W)	84 (E)	85	86 (W)	86 (E)	87	88 (W)	88 (E)
89	90	91	93	94	95	96	97
99	238	H-1	H-2	H-3
Unsigned Interstate Highways
A-1	A-2	A-3	A-4	PRI-1	PRI-2	PRI-3
Lists Two-digit Interstates - Three-digit Interstates Gaps in Interstates - Intrastate Interstates Interstate standards - Proposed Interstates

Sources

• misc.transport.road FAQ (http://www.roadfan.com/mtrfaq.html)