In 1998, with the Interstate System essentially complete, FHWA's Office of Engineering compiled information about development of the program. In making this information available to the public, we have not updated the material. All information is as of 1998 when the Office of Engineering compiled the report.
The Dwight D. Eisenhower System of Interstate and Defense Highways
Part I - History
A Brief History
Origins
Planning for what is now known as the Dwight D. Eisenhower System of Interstate and Defense Highways, commonly called "The Interstate System," began in the late 1930's. The Federal-Aid Highway Act of 1938 called on the Bureau of Public Roads (BPR), the predecessor of the Federal Highway Administration (FHWA), to study the feasibility of a toll-financed system of three east-west and three north-south superhighways. The BPR's report, Toll Roads and Free Roads, demonstrated that a toll network would not be self-supporting. Instead, the BPR's report advocated a 26,700-mile interregional highway network.
In 1941, President Franklin D. Roosevelt appointed a National Interregional Highway Committee, headed by Commissioner of Public Roads Thomas H. MacDonald, to evaluate the need for a national expressway system. The committee's January 1944 report, Interregional Highways, supported a system of 33,900 miles, plus an additional 5,000 miles of auxiliary urban routes.
Original Designation of the Interstate System
In the Federal-Aid Highway Act of 1944, the Congress acted on these recommendations. The act called for designation of a National System of Interstate Highways, to include up to 40,000 miles "... so located, as to connect by routes, direct as practical, the principal metropolitan areas, cities, and industrial centers, to serve the National Defense, and to connect at suitable border points, routes of continental importance in the Dominion of Canada and the Republic of Mexico."
On August 2, 1947, Commissioner MacDonald and Federal Works Administrator Philip B. Fleming announced selection of the first 37,700 miles. The routes had been proposed by the State highway agencies and reviewed by the Department of Defense. However, neither the 1944 act nor later legislation in the 1940's authorized funds specifically for the Interstate System. As a result, progress on construction was slow.
Interstate Funding
The Federal-Aid Highway Act of 1952 authorized the first funding specifically for System construction, but it was only a token amount of $25 million a year for fiscal years (FY) 1954 and 1955. Legislation in 1954 authorized an additional $175 million annually for FY 1956 and 1957.
Under the leadership of President Eisenhower, the question of how to fund the Interstate System was resolved with enactment of the Federal-Aid Highway Act of 1956. It served as a catalyst for the System's development and, ultimately, its completion. Title I of the 1956 Act increased the System's proposed length to 41,000 miles. It also called for nationwide standards for design of the System, authorized an accelerated program, established a new method for apportioning funds among the States, changed the name to the National System of Interstate and Defense Highway, and set the Federal Government's share of project cost at 90 percent.
Title II of the Act - entitled the Highway Revenue Act of 1956 - created the Highway Trust Fund as a dedicated source for the Interstate System.
Revenue from the Federal gas and other motor-vehicle user taxes was credited to the Highway Trust Fund to pay the Federal share of Interstate and all other Federal-aid highway projects. In this way, the Act guaranteed construction of all segments on a "pay-as-you-go" basis, thus satisfying one of President Eisenhower's primary requirements, namely that the program be self financing without contributing to the Federal budget deficit.
Interstate Cost Estimates
A new method of distributing funds among the States was necessitated by the 1956 Act and was based on each State receiving a share of the annual Interstate Construction fund authorization in the same proportion as the cost to complete its System bore to the cost of the System in all States. To achieve a simultaneous completion in all States, the Congress periodically required the BPR, and later FHWA, to develop a new estimate of the cost to complete the System and to serve as the basis for apportionments until the next estimate was prepared.
Between 1958 and 1991, 15 legislatively-mandated estimates were prepared and submitted to Congress. The final estimate, submitted in January 1991, indicated a total cost to complete the system of approximately $128.9 billion, of which the Federal share was $114.3 billion.
Additional Historical Information
The following list of books was prepared by Richard Weingroff, HPD-1, and provide the best look at the history of the Interstate System:
America's Highways 1776-1976, Federal Highway Administration, 1976. (This 550-page history discusses all aspects of American road development, including the history of the Interstate System. It is out of print but available in libraries or through inter-library loan.)
Lewis, Tom, Divided Highways: The Interstate Highway System and the Transformation of American Life, Viking Press, 1997. (Companion to an October 1997 PBS documentary of the same name.)
Rose, Mark H., Interstate Express Highway Politics 1941-1989, University of Tennessee Press, 1990 (Revised Edition). (Based on a Ph.D. thesis, this relatively short book is the best single source of information on how the 1956 legislation authorizing Interstate Highway Program came to be. The revised edition includes a chapter discussing the construction of the Interstate System.)
Seely, Bruce E., Building the American Highway System: Engineers as Policy Makers, Temple University Press, 1987. (Scholarly history of the Federal Highway Administration from its origins in 1893 as the Office of Road Inquiry to the present, with good coverage of the Interstate System.)
The States and the Interstates: Research on the Planning, Design and Construction of the Interstate and Defense Highway System, American Association of State Highway and Transportation Officials, 1991. (Interstate history from the standpoint of the State transportation departments that built this highways.)
Interstate System, critical
Goddard, Stephen B., Getting There: The Epic Struggle Between Road and Rail in the American Century, Basic Books, 1994. (The epic struggle as told by an author who wishes the railroads had defeated the "high and mighty" road builders.)
Leavitt, Helen, Superhighway-Superhoax, Doubleday and Company, Inc., 1970.
A dust jacket blurb conveyed the theme: "From Sea to Shining Sea: we are strangling in a concrete straitjacket that pollutes the environment and makes driving a nightmare."
Kelley, Ben, The Pavers and the Paved, Donald W. Brown, Inc., 1971.
Mowbray, A. Q., Road to Ruin, J. B. Lippincott Company, 1969.
ADDITIONAL READING:
Barrow, Robert Van, The Politics of Interstate Route Selection: A Case Study of Interest Activities in a Decision Situation, Ph.D. Thesis, The Florida State University, 1967.
Bryan, Mike, Uneasy Rider: The Interstate Way of Knowledge, Alfred A Knopf, 1997. (Noting that the U.S. numbered "blue" highways are a vision of the past, Bryan takes off on a "Blue Highways" type journey along the Interstate routes of the Southwest, where he finds the same types of people he would have found along the old routes.)
Coster, Graham, A Thousand Miles from Nowhere: Trucking Two Continents, North Point Press, Farrar, Straus and Giroux, 1995). (In which the author accompanies an English trucker from England to Russia and an America trucker across the United States.)
Crane, Stuart R., Federal Financing for Toll Projects Incorporated in the Interstate Highway System, Ph.D. Thesis, Indiana University, 1967.
Di Salvatore, Bryan, "A Reporter at Large: Large Cars," The New Yorker, September 12 and 19, 1988. (A two-part article about the life of a trucker on the Nation's Interstate highways.)
"40th Anniversary Special Section," Roads and Bridges, June 1996 (collection of articles on the 40th anniversary of the Interstate System).
Heppenheimer, T.A., "The Rise of the Interstates," American Heritage of Invention and Technology, Fall 1991.
Mitchell, John G., "30 Years on Ike's Autobahns," Audubon, November 1986. (An excellent look at the history and impact of the Interstate System from the perspective of a trip along I-75.)
Patton, Phil, Open Road: A Celebration of the American Highway, Simon and Schuster, 1986.
Riddick, Winston Wade, The Politics of National Highway Policy, 1953-1966, Ph.D Thesis, Columbia University, 1973.
Rose, Mark H., and Seely, Bruce E., "Getting the Interstate System Built: Road Engineers and the Implementation of Public Policy, 1955-1985," Journal of Policy History, Vol. 2, No. 1, 1990.
Schwartz, Gary T., "Urban Freeways and the Interstate System," Southern California Law Review 49 (March 1976), p. 406-513.
Sweet, James Stouder, The Federal Gasoline Tax at a Glance: A History, Bybee House, 1993 (a short history of the gas tax, available for $5.95 from Bybee House, 116 East Glendale Drive, Boone, NC 28607)
Sundstrom, Geoff, "The Paving of America: Mud and Macadam to Superhighways," Automotive News, October 30, 1985. (An excellent short history of highway development in the 20th century.)
Taylor, Nick, "Roads That Bind Us: Interstate Highways, a Guide to Rediscovering America," Travel Holiday, August 1990.
Legislative History Related to Size of the System
Federal-Aid Highway Act of 1944 -- called for designation of a National System of Interstate Highways up to 40,000 miles.
The Federal-Aid Highway Act of 1956 -- increased the authorized mileage by 1,000 miles to 41,000
The Federal-Aid Highway Act of 1968 -- authorized another 1,500 miles to a ceiling of 42,500.
The Federal-Aid Highway Act of 1968 -- also provided that the Secretary may designate, as part of the Interstate System, a highway meeting all standards for Interstate highways and that are logical additions or connections to the System. These Interstate additions are not "charged" against the legislated mileage ceiling for routes eligible for Interstate Construction funding. Codified in Section 139 of Title 23, the provision created no Federal financial responsibility for these Interstate additions.
P. L. 90-238 (Howard-Cramer Mileage) -- This 1968 act was separate from other major highway acts and provided for the addition of up to 200 miles for modifications or revisions to the basic system. The provision (and mileage added) became known by its co-sponsors, Congressmen Howard and Cramer.
The Federal-Aid Highway Act of 1973 -- increased the Howard-Cramer mileage ceiling to 500 miles.
The National Highway System Designation Act of 1995 -- in Section 332(a)(2) designated 4 high priority corridors as future Interstate routes when the Secretary determines that they meet Interstate design standards and connect to an existing Interstate route. The NHS Act created no Federal financial responsibility for these Interstate additions.
Other legislation -- Individual routes were added to the system from a reserve of undesignated mileage without increasing the legislated mileage eligible for Interstate Construction funding:
- In 1960, provisions of the Hawaii Omnibus Act led to the designation of 3 routes on the Island of Oahu, Hawaii.
- The Surface Transportation Assistance Act of 1978 provided for route additions in California and New York.
- The 1980 DOT Appropriations Act extended an Indiana route.
- The 1981 DOT Appropriations Act added a route in Alabama and extended a Missouri route.
Interstate Designations
On August 2, 1947, Commissioner Thomas MacDonald and Federal Works Administrator Philip B. Fleming announced selection of the first 37,700 miles. The routes had been proposed by the State highway agencies and reviewed by the Department of Defense. However, neither the 1944 act nor later legislation in the 1940's authorized funds specifically for the Interstate System. As a result, progress on construction was slow.
Following passage of the 1956 act, on 10/18/57, Secretary of Commerce Sinclair Weeks announced that 2,102 miles of new Interstate routes were being designated.
Following passage of the 1968 act, on 12/13/68, Transportation Secretary Alan Boyd announced that an additional 1,472.5 miles of Interstate routes had been designated in 28 States.
As a result of the Howard-Cramer provision (1968 and 1973 acts), an additional 402.62 miles of Interstate routes were designated in 9 States.
As of 12/31/97, under 23 U.S.C. 139(a), 2,108.33 miles have been added to the Interstate System in 30 States without Interstate Construction funding.
Following enactment of the NHS act in 1995, portions of high priority corridors totalling 109.7 miles have been added to the Interstate System in North Carolina and Pennsylvania.
Interstate Highway System October 18, 1957 Addition of 2,102 Miles
- The Federal-aid Highway Act of 1956 [Section 108(l)] authorized an additional 1,000 mile expansion of the Interstate System, bringing the total authorized system to 41,000 miles.
- On 10/18/57, Secretary of Commerce Sinclair Weeks announced that 2,102 miles of Interstate routes were being added to the Interstate System. The new routes included the 1,000 mile expansion plus 1,102 miles which had resulted from selections of more direct locations for routes previously designated.
- The Secretary considered 4 factors in making his selections:
- National defense.
- System integration - the value of the route as a connector between numerous centers of population and industry which generate interregional traffic.
- Industry - transportation requirements of the manufacturing, agriculture, mining, and forestry enterprises in the area traversed.
- Population.
- The added routes are categorized, depending on whether they were part of the 1,000 mile expansion or resulted from the savings in locations selected from the original designation, in the following two tables.
| The 1,000 Miles of Routes Added to the Interstate System on 10/18/57 In Accordance with Section 108(l) of the Federal-aid Highway Act of 1956 | |||
|---|---|---|---|
| State | Route | Length (Miles) | Description |
| Oregon - Washington | I-82 | 132 | Pendleton, OR to Ellenberg, WA |
| Alabama - Louisiana | I-12 | 91 | Mobile, AL to Baton Rouge, LA |
| Utah - Colorado | I-70 | 547 | Cove Fort, UT to Denver, CO |
| South Dakota - North Dakota | I-29 | 230 | Sioux Falls, SD to Fargo, ND |
| Total | 1,000 | ||
| State | Route | Length (Miles) | Description |
|---|---|---|---|
| North Carolina - Virginia West Virginia - Ohio | I-77 | 431 | Charlotte, NC to Canton, OH |
| Pennsylvania | I-79 | 102 | Pittsburgh to Erie, PA |
| Utah | I-84 | 40 | Ogden to Echo Junction, UT |
| Tennessee - Kentucky Illinois | I-24 | 170 | Nashville, TN to Cairo, IL |
| City-to-City Additions | Subtotal | 886 | |
| New Urban Connections
Chicago, IL Cincinnati, OH | |||
| Urban Connections & Belts | Subtotal | 216 | |
| Total, Rural & Urban | Total | 1,102 |
Additions to the Interstate System Segments Added on 12/13/68 in Accordance with 1968 Highway Act
- Section 14 of the Federal-Aid Highway Act of 1968 (P.L. 90-495) modified Title 23 by adding the following paragraph to Section 103(e)...
"(3) In addition to the mileage authorized by paragraphs (1) and (2) of this subsection, there is hereby authorized additional mileage of not to exceed 1,500 miles for the designation of routes in the same manner as set forth in paragraph (1), in order to improve the efficiency and service of the Interstate System to better accomplish the purposes of that System."
- On 12/13/68 Secretary Boyd announced that the U.S.DOT had allocated 1,472.5 miles, in 28 States, of the 1,500 additional Interstate miles authorized by Congress at the then estimated cost of $2.43 billion. Portions of routes added in North Carolina, Oklahoma, and Texas were already constructed to Interstate standards and were added to the system without charge.
- 27.5 miles of the authorized additional mileage was held in a reserve pool to make adjustments that might be necessary.
- The Bureau of Public Roads indicated that the States, in filing applications for the added 1,500 miles, had submitted suggested projects totalling more than 10,000 miles.
- Some of the added mileage was never constructed and was withdrawn from the Interstate System under the Interstate Withdrawal-Substitution Program; the withdrawn segments were:
- Colorado - The I-225 (renumbered I-470) SW beltway quadrant.
- Connecticut - I-82 (renumbered I-84) east of Bolton to Rhode Island State Line.
- Louisiana - The center portion of the New Orleans southern belt.
- Massachusetts - I-295 Providence belt, NE and SE quadrants
- Oklahoma - I-440 (renumbered as I-240) Oklahoma City belt
- Oregon - I-505, Portland connector
- Rhode Island - I-82 (renumbered I-84) Hartford-Providence
| State | Chief Route Number | Description | Length (Miles) | 1968 Cost ($Millions) |
|---|---|---|---|---|
| Alabama | I-565 | Huntsville spur | 19.2 | 22.9 |
| Arizona 1 | I-410 | Papago Freeway, Phase I | 4.9 | 79.8 |
| California 2 | I-15 I-380 I-605 |
| 102.5 1.6 5.5 ----- 109.6 | 201.2 31.2 19.0 ----- 251.4 |
| Colorado 3 | I-80S I-225 |
| 5.6 24.8 ---- 30.4 | 19.3 70.0 ---- 89.3 |
| Connecticut 4 | I-82 I-291 |
| 44.5 6.1 ---- 50.6 | 129.0 29.0 ----- 158.0 |
| Florida | I-75 | St. Petersburg to Miami | 252.0 | 210.0 |
| Georgia | I-185 | Columbus spur | 38.8 | 32.6 |
| Illinois | I-72 | Springfield via Decatur to Champaign | 80.0 | 56.0 |
| Indiana | I-164 | Evansville spur | 14.0 | 26.0 |
| Iowa | I-380 I-129 |
| 74.3 0.5 ----- 74.8 | 123.9 3.0 ----- 126.9 |
| Kansas | I-435 | KS portion of Kansas City west belt | 19.6 | 52.1 |
| Louisiana 5 | I-410 | New Orleans, south belt | 30.0 | 220.0 |
| Massachusetts 6 | I-295 I-295 |
| 14.3 1.5 ---- 15.8 | 44.3 3.1 ---- 47.4 |
| Michigan | I-69 | Marshall to Lansing to Flint | 96.0 | 104.4 |
| Minnesota 7 | I-894 | Radial to I-494 in Minneapolis | 9.4 | 29.0 |
| Missouri | I-435 I-435 |
| 9.0 17.0 ---- 26.0 | 14.9 39.1 ---- 54.0 |
| Nebraska | I-129 | NE portion of Sioux City spur | 1.9 | 7.8 |
| New York | I-88 | Binghamton to Schenectady | 130.0 | 210.0 |
| North Carolina | I-77 I-40 |
| 9.1 58.1 ---- 67.2 | 0.0 81.6 ---- 81.6 |
| Ohio | I-675 | Dayton, extension of I-675 belt | 3.5 | 7.3 |
| Oklahoma 8 | I-440 | Oklahoma City belt SW quadrant | 9.3 | 14.9 |
| Oregon 9 | I-505 | Portland connector | 1.1 | 11.0 |
| Rhode Island 10 | I-82 I-295 |
| 20.7 12.2 ---- 32.9 | 61.3 107.5 ----- 168.8 |
| South Carolina | I-77 | SC portion of Charlotte-Columbia route | 75.0 | 65.0 |
| Texas | I-27 I-820 |
| 125.0 13.5 ----- 138.5 | 43.1 22.0 ---- 65.1 |
| Virginia 11 | I-64 | Norfolk, west belt (ext of I-64) | 9.2 | 120.0 |
| Washington | I-182 | Tri-Cities spur | 28.0 | 25.0 |
| Wisconsin | I-43 | Milwaukee to Green Bay | 104.8 | 92.5 |
| Totals | 1,472.5 | 2,428.8 | ||
Footnotes:
| ||||
Howard-Cramer Interstate Route Additions
P.L. 90-238 (Enacted 1/2/68)
This act, which was separate from any major highway act, amended Section 103(d) of Title 23 [later renumbered as 23 U.S.C. 103(e)(2)] in order to provide sufficient mileage to enable affected States and the Secretary of Transportation to meet the problems which had been encountered in attempting to construct certain mostly urban Interstate segments.
Under the act, if a State and the Secretary agreed that a portion of an Interstate route was not essential to a unified and connected system and would not be constructed as part of the System, the Secretary could redesignate the withdrawn mileage, plus additional miles (if necessary) from the 200 miles made available by the act, to other Interstate routes or route portions.
The act required that the cost of all mileage used for these modifications would be no greater than the cost of the withdrawn mileage as reported in the 1965 Interstate Cost Estimate (ICE).
Federal-Aid Highway Act of 1973 (P.L. 93-86)
Section 137 of this act amended 23 U.S.C. 103(e)(2) and increased the additional mileage for the Howard-Cramer modifications from 200 to 500 miles. It also revised the cost limitation to that amount included in the 1972 ICE.
Surface Transportation Assistance Act of 1978 (P.L. 95-599)
Section 107 of this act further amended 23 U.S.C. 103(e)(2) and removed the provision limiting Interstate Construction funding to the amount reported in the 1972 ICE. As a result the Howard-Cramer route additions were funded at a full 90 percent Federal share, the same as all other Interstate routes designated under Section 103(e).
Section 107 also amended 103(e)(2) by prohibiting the redesignation of any additional Interstate mileage under Section 103(e)(2) after the enactment date, November 6, 1978.
Howard-Cramer Designations
As a result of the above provisions, a total of 402.62 miles of Interstate routes, or portions thereof, were designated in 9 States as shown on the following table and maps.
| State | Route | Length (Miles) | Description |
|---|---|---|---|
| California | 105 | 7.00 | Century Freeway in L.A., from Lynnwood to I-605 |
| Connecticut | 691 | 6.69 | From east of I-84 to I-91 at Meriden |
| Florida | 75 | 46.31 | Tampa Bypass - From Bradenton to I-275 north of Tampa |
| Georgia | 520 | 9.11 | Augusta Loop |
| 575 | 29.16 | Spur from I-75 at Marietta, north | |
| 675 | 7.78 | Connector south of Atlanta | |
| Louisiana | 49 | 153.18 | From U.S. 190 at Opelousas to U.S. 84 at Grand Bayou |
| Massachusetts | 495 | 12.90 | From S.R. 24 to I-95, south of Boston |
| Maryland | 97 | 14.90 | From U.S. 50 at Annapolis to I-695 at Baltimore |
| 195 | 2.20 | Spur to BWI Airport | |
| 370 | 1.18 | Spur from I-270 to Shady Grove | |
| 595 | 19.31 | U.S. 50 from Capital Beltway to Annapolis | |
| New Jersey | 195 | 27.30 | From NJ Turnpike east of Trenton to Garden State Parkway |
| New York | 390 | 60.50 | From Cohocton to I-490 at Rochester |
| 590 | 5.10 | From I-390 to I-490 at Rochester | |
| Total | 402.62 | ||
Individual Routes (And Route Segments) Added to the Interstate System By Special Legislation
P.L. 86-624 -- Hawaii Omnibus Act -- Enacted 7/12/60
- Section 17 of this act amended 23 U.S.C. and
- removed the limitation that the Interstate System be designated entirely within the continental United States;
- provided for the apportionment from the Highway Trust Fund to Hawaii of $12.375 million of Interstate funds for F.Y. 1962; and
- provided for the apportionment to Hawaii of Interstate funds for subsequent years in accordance with 23 U.S.C. 104(b)(5).
- In August 1960 the Federal Highway Administrator approved the addition of H-1, H-2 and H-3 on the Island of Oahu. These additions were included in the 1961 Interstate Cost Estimate.
P.L. 95-599 -- Surface Transportation Assistance Act (STAA) of 1978 -- Enacted 11/6/78
- Section 140 of the 1978 STAA specified that Interstate Routes be designated for:
- 20.5 miles of existing State Route 11 (Harbor Freeway) in the City of Los Angeles, California between I 10 and State Route 47 / Community of San Pedro (This route became I 110).
- 4.2 miles of the proposed Lockport Expressway in the town of Amherst, Erie County, New York (This route became I-990 in the Buffalo area).
- 5.1 miles of proposed I-481 connecting Exit 34-A of I-90 to the Bear Road Interchange of I 81 in Onondaga County, New York (This route became part of the I-481 loop at Syracuse).
P.L. 95-240 -- Supplemental Appropriations Act for 1978 -- Enacted 3/7/78
- Section 209 of this 1978 act provided for the designation of a 1.5 mile spur in Tacoma, Washington (This route became I-705).
P.L. 96-131 -- 1980 Appropriations Act -- Enacted 11/30/79
- Section 311 of the 1980 act provided for a 6-mile extension of I-164 in Evansville, Indiana.
P.L. 96-400 -- 1981 Appropriations Act -- Enacted 10/9/80
- Section 310 of the 1981 act provided for a 3.03 mile extension of I-170 in St. Louis, Missouri, and the addition of 6.25 miles for I-210 in the vicinity of Mobile, Alabama. I-210 was later shorted and renumbered as I-165 pursuant to Section 133(f) of the Surface Transportation and Uniform Relocation Act of 1987.
| Interstate Route Additions Under 23 U.S.C. 139(a) As of 12/31/97 | |||
|---|---|---|---|
| State | Number of Routes | Routes Added | Total Length |
| Arkansas | 2 | I-440, I-540 | 15.93 |
| California | 7 | I-215, I-238, I-580, I-680, I-710, I 880, I-980 | 141.80 |
| Connecticut | 1 | I-395 | 54.69 |
| Florida | 3 | I-175, I-375, I-595 | 11.58 |
| Georgia | 3 | I-185, I-516, I-985 | 36.30 |
| Hawaii | 1 | H-201 | 4.10 |
| Illinois | 8 | I-39, I-72, I-88, I-90, I-155, I-172, I-190, I-355 | 445.03 |
| Indiana | 2 | I-465, I-469 | 34.63 |
| Kansas | 1 | I-335 | 50.10 |
| Kentucky | 1 | I-265 | 21.20 |
| Louisiana | 1 | I-49 | 19.55 |
| Maine | 1 | I-495 | 50.50 |
| Maryland | 4 | I-68, I-195, I-695, I-795 | 89.37 |
| Massachusetts | 6 | I-90, I-93, I-95, I-195, I-395, I-495 | 99.61 |
| Michigan | 1 | I-69 | 66.80 |
| Missouri | 2 | I-64, I-170 | 18.99 |
| Nevada | 2 | I-515, I-580 | 16.11 |
| New Hampshire | 1 | I-293 | 5.68 |
| New York | 5 | I-87, I-478, I-495, I-678, I-990 | 104.24 |
| North Carolina | 6 | I-40, I-77, I-240, I-277, I-440, I-540 | 127.54 |
| Ohio | 1 | I-80 | 35.00 |
| Oklahoma | 3 | I-44, I-235, I-240 | 120.65 |
| Oregon | 1 | I-84 | 6.89 |
| Pennsylvania | 2 | I-180, I-476 | 138.80 |
| South Carolina | 3 | I-77, I-385, I-526 | 56.70 |
| Tennessee | 2 | I-140, I-181 | 35.00 |
| Texas | 5 | I-20, I-27, I-30, I-44, I-410 | 69.46 |
| Virginia | 2 | I-95, I-664 | 33.28 |
| West Virginia | 1 | I-68 | 31.80 |
| Wisconsin | 2 | I-39, I-43 | 167.00 |
| 30 States | 80 | Total Length 2,108.33 | |
| Interstate Route Additions Under 23 U.S.C. 139(a) As of 12/31/97 | ||||
|---|---|---|---|---|
| State | Route | Date Added | Termini | Length |
| Arkansas | I-440 | 1/14/80 | East Belt Freeway Fr: I-30 Little Rock To: I-40 East of Little Rock | 9.96 |
| I-540 | 12/08/78 | Fr: I-540/AR 22 at Fort Smith To: US 271 South of Fort Smith | 5.97 AR Total 15.93 | |
| California | I-215 | 9/16/97 | CA 215/Old US 395/Old CA 194 Fr: I-15 Murrieta, North of Temecula To: I-215/CA 60 East of Riverside | 29.40 |
| I-215 | 12/04/73 | US 395 Fr: S Int CA 60 at Riverside To: I-10/I-215 San Bernardino | 11.30 | |
| I-215 | 2/01/72 | US 395/Old Location I-15 Fr: I-10 at San Bernardino To: I-215 Devore NW of San Bernardino | 13.80 | |
| I-238 | 5/18/83 | CA 238 Fr: I-880 at San Lorenzo To: I-550 at Castro Valley | 2.10 | |
| I-580 | 4/20/78 | Fr: US 101 at San Rafael To: I-580/Castro St. at Richmond | 7.30 | |
| I-680 | 7/13/73 | CA 21, Luther Gibson Freeway Fr: I-80 at Cordelia To: I-780 at Benicia | 12.50 | |
| I-710 | 9/28/83 | CA 7 - Long Beach Freeway Fr: I-10 at Monterey Park To: CA 1 at Long Beach | 19.70 | |
| I-880 | 5/18/83 | CA 17, Nimitz Freeway Fr: I-80 at Berkeley To: I-280 at San Jose | 44.70 | |
| I-980 | 1/29/76 | CA 24 Fr: I-580 at Oakland To: I-980, 0.8 mi N of I-880/CA 17 | 1.00 CA Total 141.80 | |
| Connecticut | I-395 | 4/18/83 | CT 52 Fr: I-395 at Massachusetts State Line To: I-95 at East Lyme | 54.69 |
| Florida | I-175 | 5/20/82 | South Downtown Distributor Fr: I-275 at St. Petersburg To: FL 687 | 1.44 |
| I-375 | 5/20/82 | North Downtown Distributor Fr: I-275 at St. Petersburg To: FL 595 West of FL 687 | 1.34 | |
| I-595 | 6/11/90 | FL 84 Fr: I-75 at Andytown To: US 441 at Fort Lauderdale | 8.8 FL Total 11.58 | |
| Georgia | I-185 | 3/06/84 | GA 411/Lindsey Creek Bypass Fr: I-185/US 80/GA 22 at Columbus To: US 27/280/Victory Dr at Columbus | 5.50 |
| I-516 | 6/20/84 | GA 21, Lynes Parkway Fr: US 17/80 Connector NW of Savannah To: Mildred St S of I-16 & W of GA 20 | 6.40 | |
| I-985 | 6/20/84 | US 23 / GA 365 Fr: I-85 at Suwanee, NE of Atlanta To: GA 13 at Gainesville | 24.40 GA Total 36.30 | |
| Hawaii | H-201 | 11/01/89 | HI 78 Fr: H-1/3 Halawa To: H-1 Fort Shafter | 4.10 |
| Illinois | I-39 | 12/12/85 | US 51 Fr: I-90 at Rockford To: I-80 at LaSalle | 63.89 |
| I-39 | 12/10/92 | US 51 Fr: I-80 at LaSalle To: I-74 at Bloomington | 55.70 | |
| I-72 | 5/10/95 | US 36 / Central Illinois Expressway Fr: I-172/IL 336 SE of Quincy To: I-55 at Springfield | 94.00 | |
| I-88 | 6/26/87 | East-West Tollway Fr: I-80 at Moline To: I-290 at Chicago | 140.59 | |
| I-90 | 9/14/77 | NW Tollway - JFK Expressway Fr: I-290 at Schaumburg To: NW int I-94/Edens Expy in Chicago | 16.71 | |
| I-155 | 12/10/95 | IL 121 Fr: I-74 at Peoria To: I-55 at Lincoln | 32.06 | |
| I-172 | 5/10/95 | IL 336 / Central Illinois Expressway Fr: US 24 NE of Quincy To: I-72/US 36 | 19.00 | |
| I-190 | 10/25/78 | Fr: Chicago O'Hare International Airport To: I-90 in Chicago | 3.07 | |
| I-355 | 3/30/90 | IL 53 Fr: I-290 Itasca, NW of Chicago To: I-55 Bollingbrook, SW of Chicago | 20.01 IL Total 445.03 | |
| Indiana | I-465 | 1/7/70 | Fr: I-465 Exit 25, NW of Indianapolis To: I-65 Exit 123, at Indianapolis | 5.03 |
| I-469 | 10/12/95 | New IN 469 Fr: I-69 NE of Fort Wayne To: I-69 SW of Fort Wayne | 29.60 IN Total 34.63 | |
| Kansas | I-335 | 10/21/87 | Kansas Turnpike Fr: I-470 at Topeka To: I-35 at Emporia | 50.10 |
| Kentucky | I-265 | 11/02/87 | KY 841 / Gene Snyder Freeway Fr: I-71 NE of Louisville To: I-65 South of Louisville | 21.20 |
| Louisiana | I-49 | 10/22/81 | US 167 Fr: I-49/US 190 at Opelousas To: I-10 at Lafayette | 19.55 |
| Maine | I-495 | 8/11/87 | Maine Turnpike Fr: I-95 at Gardiner To: I-95 at Portland | 50.50 |
| Maryland | I-68 | 6/03/91 | US 48 Fr: I-68 at West Virginia State Line To: I-70 at Hancock | 80.30 |
| I-195 | 7/28/75 | Metropolitan Blvd (BWI Airport Entrance) Fr: I-95 Exit 47 / MD 166 To: I-195/US 1 at Elkridge | 1.40 | |
| I-695 | 6/28/76 | Baltimore Beltway Fr: I-695/MD 295/Balt-Wash Parkway To: I-97 Exit 17 / MD 3 | 2.20 | |
| I-795 | 3/04/91 | Northwest Expressway Fr: MD 140 at Reisterstown To: I-795/Dolfield at Owings Mills | 5.47 MD Total 89.37 | |
| Massachusetts | I-90 | 4/23/90 | Massachusetts Turnpike Fr: I-90 Allston Exit To: I-93 in Boston | 2.90 |
| I-93 | 5/23/74 | MA 3 / MA 128 Fr: I-93 at Mass Ave To: I-95 Exit 12 at Canton | 14.10 | |
| I-95 | 1/10/75 | MA 128 Fr: I-95/NW Int MA 128 at Peabody To: I-93 Exit 1 at Canton | 37.54 | |
| I-195 | 1/10/75 | Fr: I-495 Exit 1 / MA 25 at Wareham To: I-195 WS Acushnet Rv at New Bedford | 14.28 | |
| I-395 | 4/18/83 | MA 52 Fr: I-90/I-290 at Auburn To: I-395 at Connecticut State Line | 12.29 | |
| I-495 | 1/10/75 | MA 25 Fr: MA 24 at Rayham To: I-195 Exit 22 / MA 25 at Wareham | 18.50 MA Total 99.61 | |
| Michigan | I-69 | 9/04/73 | MI 21 Fr: I-75 Exit 117A at Flint To: I-475 Exit 6 at Flint | 3.20 |
| I-69 | 2/10/87 | MI 21 Fr: I-475 Exit 6 at Flint To: I-94 Exit 271 at Port Huron | 63.60 MI Total 66.80 | |
| Missouri | I-64 | 8/08/87 | US 40 Fr: I-270 West of St Louis To: I-55/70 at St Louis | 14.70 |
| I-170 | 4/08/86 | MO 725 Fr: Page Ave/Rte D Overland To: I-64/US 40 at Richmond Heights | 4.29 MO Total 18.99 | |
| Nevada | I-515 | 11/01/94 | New US 93/95 - Boulder Highway, NV 582 Fr: Sand Hill Road at Las Vegas To: "Wagon Wheel" Intch at Henderson | 14.90 |
| I-580 | 11/24/78 | US 395/North-South Freeway Fr: I-80 at Reno To: Mill St at Reno | 1.21 NV Total 16.11 | |
| New Hampshire | I-293 | 8/09/76 | Everett Turnpike Fr: I-93 North of Manchester To: US 3 at Manchester | 5.68 |
| New York | I-87 | 9/11/69 | NY Thruway Fr: I-84 at Newburgh To: W int I-287/NY 17 at Suffern | 29.80 |
| I-478 | 11/12/71 | Brooklyn-Battery Tunnel Fr: North end of tunnel in Manhattan To: I-278/Brooklyn-Queens Expressway | 1.90 | |
| I-495 | 11/12/71 | Queens-Midtown Tunnel Fr: West end of tunnel in Manhattan To: I-278/Brooklyn-Queens Expressway | 3.10 | |
| I-495 | 10/25/83 | Long Island Expressway Fr: I-678/Van Wyck Expressway (Queens) To: NY 25 in Suffolk | 59.60 | |
| I-678 | 4/28/75 | Van Wyck Expressway Fr: I-495 Long Island Expressway To: JFK Intl Airport in Queens | 7.80 | |
| I-990 | 7/28/93 | Fr: CR 299/French Rd NE of Buffalo To: NY 263 / Millersport Highway | 2.04 NY Total 104.24 | |
| North Carolina | I-40 | 6/15/09 | Fr: I-95 at Benson To: NC 132 at Wilmington | 91.40 |
| I-77 | 12/27/68 | Fr: US 512/Woodlawn Rd in Charlotte To: SC State Line | 5.80 | |
| I-240 | 1/26/76 | Fr: US 70/74 East int E of Asheville To: US 74 E int SE of Asheville | 1.71 | |
| I-240 | 4/21/76 | NC 191 - US 19/23 - US 70/74 Fr: I-26/I-40 West of Asheville To: Charlotte St North of Asheville | 5.21 | |
| I-277 | 4/26/78 | Northwest Expressway at Charlotte Fr: I-77 Exit 11/NC 16 To: Tenth/McDowell Streets | 1.72 | |
| I-440 | 3/26/91 | Raleigh Beltline Fr: I-40 SW of Raleigh To: I-40 SE of Raleigh | 16.70 | |
| I-540 | 1/29/97 | Northern Wake Expressway Fr: I-40/Raleigh-Durham Intl Airport To: US 70 | 5.00 NC Total 127.54 | |
| Ohio | I-80 | 1/23/70 | Ohio Turnpike Fr: I-480 SW of Cleveland To: I-480 SE of Cleveland | 35.00 |
| Oklahoma | I-44 | 8/26/82 | Bailey Turnpike Fr: I-240 at Oklahoma City To: Texas State Line | 114.76 |
| I-235 | 5/13/76 | US 77 / Central Expressway Fr: I-44 Exit 127 at Oklahoma City To: 36th Street NW | 1.54 | |
| I-240 | 12/24/68 | US 62 / OK 3 / South Bypass Fr: I-44 at Oklahoma City To: I-35 | 4.35 OK Total 120.65 | |
| Oregon | I-84 | 3/08/84 | US 30 / Banfield Expressway Fr: I-5 at Portland To: I-205 | 6.89 |
| Pennsylvania | I-180 | 9/23/83 | US 220 / PA 147 Fr: US 15 at Williamsport To: I-80 at Milton | 28.80 |
| I-476 | 10/24/96 | NE Extension, Pennsylvania Turnpike Fr: I-276/476 at Philadelphia To: I-81 North of Scranton | 110.00 PA Total 138.80 | |
| South Carolina | I-77 | 8/14/95 | Fr: I-20 NE of Columbia To: SC 48 South of Columbia | 9.50 |
| I-385 | 2/13/84 | US 276 Fr: I-85 at Greenville To: I-26 at Clinton | 36.00 | |
| I-526 | 8/05/92 | Mark Clark Expressway Fr: East end of Wando River Bridge To: US 17 at Mt Pleasant | 3.60 | |
| I-526 | 1/05/90 | Mark Clark Expressway Fr: I-26 North of Charleston To: US 17 West of Charleston | 7.60 SC Total 56.70 | |
| Tennessee | I-140 | 5/27/97 | Pellissippi Parkway Fr: I-40/TN 162 West of Knoxville] To: US 129 North of Alcoa | 11.20 |
| I-181 | 12/04/85 | US 23 Fr: TN 1 at Kingsport To: US 321/TN 67 at Johnson City | 23.80 TN Total 35.00 | |
| Texas | I-20 | 7/03/84 | Fr: I-30 West of Fort Worth To: I-20, 2 miles East of I-30 | 2.00 |
| I-27 | 12/13/68 | US 87 Fr: I-40 at Amarillo To: I-27 Exit 110/US 87, N of Canyon | 12.90 | |
| I-30 | 9/14/71 | Former Dallas-Fort Worth Turnpike Fr: I-35W at Fort Worth To: I-35E at Dallas | 29.93 | |
| I-44 | 7/03/84 | US 281 Fr: Oklahoma State Line To: 8th Street in Wichita Falls | 14.70 | |
| I-410 | 7/07/69 | Fr: I-10 Exit 564 NW of San Antonio To: I-35 Exit 166 NE of San Antonio | 9.93 TX Total 69.46 | |
| Virginia | I-95 | 3/21/86 | Richmond-Petersburg Turnpike Fr: I-64 in Richmond To: I-85 in Petersburg | 24.08 |
| I-664 | 5/04/92 | Fr: South Shore of Hampton Roads To: I-64 at Bowers Hill | 9.20 VA Total 33.28 | |
| West Virginia | I-68 | 6/03/91 | US 48 Fr: I-79 at Morgantown To: Maryland State Line | 31.80 |
| Wisconsin | I-39 | 1/11/96 | WI 78 - US 51 Fr: I-90/94 at Portage To: South Int WI 29 at Wausau | 104.00 |
| I-43 | 11/24/87 | WI 15 Fr: I-90 at Beloit To: I-894 at Milwaukee | 63.00 WI Total 167.00 | |
| Total Mileage 2,108.33 | ||||
High Priority Route Additions in Accordance With The National Highway System Designation Act of 1995
The National Highway System Designation Act of 1995 (P.L. 104-59) amended Section 1105 of the Intermodal Surface Transportation Efficiency Act (ISTEA) of 1991 (P.L. 102-240) to designate all or parts of four National Highway System high priority corridors as future parts of the Interstate System. Section 1211 of the Transportation Equity Act for the 21st Century (P.L. 105-178) modified the descriptions for three of these corridors and designated five additional corridors as future parts of the Interstate System. Interstate route numbers for four of the corridors are also specified by these Acts.
General descriptions and Route numbers of the Nine Corridors
- Kansas City, Missouri to Shreveport, Louisiana
- Georgetown, South Carolina to Portsmouth, Ohio (I-73 and I-74)
- Bedford, Pennsylvania to Corning, New York (I-99)
- Sarnia, Ontario, Canada to Chicago, Illinois, and Sarnia, Ontario, Canada to the U.S./Mexico Border in the Lower Rio Grande Valley, Texas (I-69)
- Laredo, Texas to Texarkana, Texas (I-69)
- Harriman, New York to Erie, Pennsylvania
- Lafayette, Louisiana to New Orleans, Louisiana
- Danville, Virginia to Greensboro, North Carolina
- Batesville, Mississippi to Birmingham, Alabama
Funding Eligibility
Construction and improvement of these corridors are eligible for funds under the National Highway System program and the Surface Transportation Program, and bridge improvements may be funded under the Highway Bridge Program. When segments of these corridors are added to the Interstate System, they become eligible for Interstate Maintenance (IM) funds and their lane-miles are included in the formula for subsequent IM apportionments. Planning and development of high priority corridors are also eligible for funding under the discretionary National Corridor Planning and Development Program.
Signing
Interstate route signs may be erected when the Secretary adds a segment to the Interstate System after determining that it has been built to Interstate standards and connects with another Interstate segment. Informational signs may be erected to identify corridors (or segments of corridors) as future parts of the Interstate System in accordance with guidance contained in 23 CFR 470, Appendix C. Unless specified in legislation, i.e., I-69, I-73, I-74, and I-99, proposed Interstate route numbers must be submitted by the State(s) to American Association of State Highway and Transportation Officials for approval with concurrence by the Federal Highway Administration.
Segments Completed and Signed as Interstate Routes
The portions of these routes added to the Interstate System as of 6/30/98 are shown in the following table.
| State | Route | Date Added | Termini | Length |
|---|---|---|---|---|
| Pennsylvania | I-99 | 1/26/96 | US 220 (High Priority Corridor 9) Fr: Penn Turnpike at Bedford To: PA 350 at Bald Eagle | 53.00 |
| North Carolina | I-73 | 8/27/96 | US 220 (High Priority Corridor 5) Fr: US 220 A at Emery To: I-40 at Greensboro | 56.70 |
| Total Mileage 109.70 | ||||