# A Study to Eliminate Cardinal Initials on Interstate Routes and Other Needed Changes in Interstate Route Numbering

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January 18, 1973
A STUDY TO ELIMINATE CARDINAL INITIALS ON INTERSTATE ROUTES AND OTHER NEEDED CHANGES IN INTERSTATE ROUTE NUMBERING BY AASHO REPRESENTATION ON NACUTCD AND OTO-FHWA JANUARY 18, 1973
In accordance with the agreement reached between Mr. F. C. Turner, formerly Federal Highway Administrator, and Mr. A. E. Johnson, Executive Director of AASHO, members of the Office of Traffic Operations met with the AASHO membership to the National Advisory Committee during the NAC meeting on July 19 and 20, 1972, and discussed this study. It was agreed at that time that OTO would prepare a base map with additional detail maps depicting the suggested changes in Interstate route numbering and transmit copies to each AASHO member and alternate of the NAC for their review. This matter was discussed at the January, 1973 meeting of NAC.
The base map has been prepared showing the location or item number, existing Interstate route numbers and proposed changes in a few of these numbers. In addition a separate packet has been prepared for each item number consisting of the general Interstate location in and around urban areas, sections of the appropriate State map and urban area cutouts, all at a larger scale.
The following comments are offered for further explanation of action proposed for each location or item number.
Item #1 - Florida - Tampa Bay Area
Presently I-75 is being designed to split north of Tampa with the eastern leg designated I-75E and the western leg through Tampa, St. Petersburg and across the Sunshine Skyway Bridge to Palmetto designated as I-75W. In an effort to remove the cardi­nal initials from the route number, the State has suggested that I-75 be routed over the east leg and the west leg be numbered either I-175 or I-275. The determination of the three-digit number being odd or even will depend on whether the portion of presently designated Interstate from the north end of the Sun­shine Skyway Toll Bridge and Causeway south to Palmetto is to remain on the System. In either case the beginning of I-4 would be at the junction of I-175 or I-275 in Tampa. Concurrence in the State's desires is recommended.
I-75 presently enters Macon from the northwest, junctions with I-16 in Macon then turns southwesterly through Macon and con­tinues south into Florida. I-475 originates at a junction with I-75 northwest of Macon and bypasses the city on the west side and joins 1-75 south of Macon. It is believed that the majority of I-75 traffic is destined for Atlanta in the northbound direc­tion and southern Georgia and Florida in the southbound direction without desiring to travel through Macon. Therefore, it is recom­mended that I-475 be changed to I-75, I-16 be extended northwester­ly to the present junction of I-75 and I-475, and the north-south section of present I-75 in Macon be changed to either I-475 or I-216. It is understood that the State is not in favor of this change due to the business interests in Macon.
Item #3 - Louisiana - New Orleans Area
The routing of I-10 is such that it enters New Orleans from the west then turns southeast to the downtown area then makes a 90° turn to the northeast. I-610 is located through the northern portion of New Orleans and bypasses the business district. The State recommends the switching of the route numbers in this area as soon as I-610 is completed and opened to traffic. Concurrence in the State's position is recommended.
Item #4 - Texas - Dallas - Ft. Worth Area
Some changes were made in the Interstate routes in this area during September 1971. Presently I-35 originating in south Texas splits just north of Hillsboro into I-35E going through Dallas and I-35W through Ft. Worth and joining again southwest of Denton into the single route of I-35. Other existing routes in this area having a bearing on this situation are as follows:
   (a) I-20 has recently been changed and is now located south of downtown Ft. Worth and Dallas and inter­sects existing I-20 east of Dallas.
   (b) I-30 has recently been extended to the west of Ft. Worth and follows previous I-20 through Ft. Worth, the Dallas-Ft. Worth Toll Road and previous I-20 in Dallas to the original beginning point of I-30.
In an effort to eliminate the cardinal initials on I-35 the follow­ing changes are recommended:
   (a) Renumber the section of I-35E from north of Hillsboro ​to Dallas as I-30. This will extend I-30 from north of Hillsboro to Little Rock, Arkansas.
   (b) Renumber the section of I-35E from Dallas to Denton as I-45. This will extend I-45 from Galveston to Denton.
   (c) Renumber the entire length of I-35W as I-35.
   (d) Renumber the existing loop I-635 in Dallas as I-645.
   (e) Renumber the existing section of I-30 from west of Ft. Worth to downtown Dallas as either I-230 or I-245. Since this is primarily an east-west route and is a continuation of I-30 we suggest the use of I-230.
Item #5 - Oklahoma - Oklahoma City Area
Presently there are two loop routes in the metropolitan area; I-440 in the northwest quadrant and I-240 in the southwest and southeast quadrants. It is the State's desire to number the en­tire loop route as I-240 when construction is completed and the route opened to traffic. Approval is recommended.
Item #6 - Tennessee - Memphis
There are two loop routes presently approved in the Memphis area; I-240 in the north, east and south portions of the city and I-255 in the west portion starting at the south junction of I-55 and I-240 and going north to the junction of I-40. The State desires to renumber the I-255 portion of the loop as I-240. Approval is recommended.
Item #7 - Kansas - Wichita & Salina
I-35W begins at its junction with I-35 in the south edge of Wichita and continues northerly 95.7 miles to its junction with I-70 northwest of Salina. To eliminate the cardinal initial on this route it is recommended that the route number be changed to I-31, an unused number. Since I-235 in Wichita is a loop route which actually begins and ends on I-35W rather than I-35, it is recommended that it be changed to I-231.
Item #8 - Colorado & Nebraska
The approved routing of I-80S begins at a junction of I-70 northwest of the downtown area of Denver and continues ​northeasterly to its junction with I-80 in Nebraska. The total length is 186.3 miles of which 184.2 miles are in Colorado and 2.1 miles are in Nebraska. To remove the cardinal initial from this route it is necessary to renumber it as an even numbered route. Also since it originates at a junction with I-70, it is believed that the route number chosen should be in the 70 series of numbers. All even numbered routes in the 70 series have already been used in other, sections of the country; however, it is believed that a specific route number can be used to designate two separate routes as long as the length of these routes is rather short, the route number does not designate a major route, and the two routes are located in separate sections of the country. If this criterion is used it is believed that the likelihood of driver confusion would be nil. Therefore, route number I-78 was chosen since the total length of existing I-78 is 146.8 miles and is located in Pennsyl­vania, New Jersey and New York. If it is desired not to use the same number on two widely separated sections of Interstate, this route could be numbered I-23.
Item #9 - Illinois - Peoria - East Peoria Area
Presently the approved location of I-474 is to the west and south of the Peoria - East Peoria area with I-74 going through the center of the metropolitan area. The State desires to switch these routes upon the completion of construction to provide route continuity for through traffic wishing to bypass the downtown area. Approval is recommended.
Item #10 - Iowa - Illinois - Quad-City Area
In the Quad-City area (Davenport and Battendorf, Iowa, and Rock Island and Moline, Illinois), there exists three Interstate routes having various Interchange geometries which have caused serious traffic operation difficulties. The major difficulty is the cloverleaf Interchange southeast of Moline, Illinois, where I-80 traffic westbound is required to exit on the outer ramp of the cloverleaf to turn north and remain on I-80. Likewise the eastbound traffic on I-80 is required to exit onto the southwest loop of this Interchange to remain eastbound on I-80. Also all traffic on I-74 desiring to remain on that route are required to make exit maneuvers.
The approved location of I-280 is in the west and southwest por­tion of the area and starts at the junction with I-80 northwest of the area. This Interchange is a directional and certainly more suitable for accommodating the various movements than the cloverleaf southeast of the area. Therefore, the following changes ​are recommended.
   (a) Renumber present I-280 and the east-west section of I-74 as I-80.
   (b) Renumber the east and north sections of I-80 as I-74.
   (c) Renumber the north-south section of I-74 which is located through the urban area as either I-274 or I-280.
The above changes would also eliminate the present 9.4 mile over­lap of I-74 and I-280 south of Moline.
Item #11 - Illinois - Chicago Area
There are several changes which the State desires to make in the numbering of Interstate routes in the Chicago area. A summary of these is as follows.
   (a) Reroute I-90 over the Dan Ryan and John F. Kennedy Expressways and the northwest tollway.
   (b) Reroute I-94 north on its existing location; then west along the proposed route of I-494 to join the Edens Expressway. This would delete route number I-494.
   (c) Route I-290 from the Rohlwing Road interchange with the Northwest Tollway, south and east along the Eisenhower Expressway to its junction with I-90 (Dan Ryan Express­way).
It appears that the above changes would improve traffic operations in the area and eliminate several overlapping routes. Routes I-294 and I-80 are to remain unchanged. The above changes are recommended upon completion of the routes involved.
One additional item affecting the Chicago area is the routing of I-57. Within the last few years the State of Wisconsin has added an Interstate route from Milwaukee to Green Bay and selected I-57 as the route number. They also have requested Illinois to sign the route through Chicago to the Wisconsin line. This would result in overlapping of I-57 with other complicated routes in the Chicago area and also an overlap of I-94 from Chicago to Milwaukee. To alleviate this situation it is recommended that I-57 in Wisconsin be renumbered as I-39.
There are several changes which both States desire to make in the numbering of Interstate routes in the St. Louis - East St. Louis area.
A summary of these is as follows.
   (a) With the completion of a proposed connection in the northwest quadrant of the area, the north leg of I-270 would be renumbered as I-70.
   (b) With the completion of a proposed connection in the northeast quadrant of the area, a complete loop route would exist on the west, south and east sides of the area and would be designated as I-270. This would eliminate routes I-244 and I-255.
   (c) Extend I-64 to the northwest starting at the junction with proposed I-70 and continue in a southeasterly direction through the downtown area of St. Louis to the connection with existing I-64 in East St. Louis.
It is believed these changes would provide more continuity in routes, relieve the downtown area of through traffic all resulting in im­proved traffic operations. These changes are recommended for approval at such time as the needed construction is completed.
Item #13 - Minnesota - Minneapolis - St. Paul Area
The only reasonable solution to eliminate the cardinal initials from the routes in this area is to renumber one of the routes as a loop designation. The length of I-35W through Minneapolis is 41.8 miles long and I-35E through St. Paul is 39.0 miles in length. It is also understood the alinement and geometries are somewhat more complicated along I-35W when compared to those of I-35E. It is believed that through traffic should travel the more direct and less confusing route; therefore, it is recommended that I-35E be renumbered as I-35 and I-35W be redesignated as I-235. It may be desirable to combine I-694 and I-494 into a single belt route.
Item #14 - Ohio - Akron
It is recommended this change be approved provided the existing geometries are adequate for satisfactory operations. It should be noted that route number I-80S has been deleted throughout the State of Ohio and renumbered as I-76. This change has received both AASHO and FHWA approval.
Item #15 - Ohio - Columbus
This is similar to the Item #14 wherein the State is considering the renumbering of the north leg of I-70 in downtown Columbus as I-670. It is recommended that this change be made provided the geometries are adequate for satisfactory operations.
Item #16 - Maryland & District of Columbia - Baltimore Washington, D. C.
In their previous response to the initial phase of this study the Maryland DOT expressed their desire to eliminate the cardinal initials from routes I-70N and I-70S. It is their recommendation to renumber I-70N as I-70 and I-70S as I-370. Since it is be­coming apparent that I-70S will not be constructed within the District of Columbia the proper termination point of I-70S would be at its Interchange with I-495 in the northwest section of the metropolitan area. It is, therefore, recommended that I-70N be changed to I-70. However, since I-70S connects at both ends to another Interstate route, it is recommended that it be changed to I-270 rather than I-370. In addition it is believed that the use of the I-270 route number would solve the signing and some of the operation problems in this area since the west leg of the present I-70 - I-495 Interchange complex is designated as I-270.
Item #17 - Delaware - Wilmington
The State is contemplating the switching of I-95 and I-495 in the Wilmington area as soon as construction progresses to a point of serviceability.
Item #18 - Pennsylvania & New Jersey - Philadelphia - Camden Area
The changes in routes I-76 and I-676 as shown on the attached packet for this item number have recently been approved by AASHO and FHWA approval was given on August 28, 1972.
Item #19 - Iowa & Nebraska - Council Bluffs - Omaha Area
Upon the completion of I-680 in this area, the Iowa State Highway Commission has stated that they will consider renumbering I-80N as I-680 and route I-680 over I-29 for an 11 mile overlap. This ​change is recommended.
Item #20 - Idaho - Pocatello
To eliminate the cardinal initial from the 62.5 mile route of I-15W, it is recommended that the route be renumbered as I-215.
Item #21 - Utah, Idaho & Oregon
The approved routing of I-80N in these three States begins in Portland, Oregon, and continues easterly and southeasterly through Boise, Idaho, to Tremonton, Utah, where it overlaps I-15 for 36.0 miles to Ogden, Utah, thence southeasterly to a junction with I-80 at Echo Junction, Utah. The total route length is 790.2 miles in­cluding the overlap section with I-15. This is similar to Item #8 since to eliminate the cardinal initial from this route it is necessary to renumber the entire route. Since the route is gen­erally an east-west route and junctions with I-80 the route number should be an even-numbered route in the 80 series. All even num­bers in the 80 series have already been used in other sections of the country, however, as stated under Item #8, it is believed that a specific route number can be used to designate two separate routes in separate sections of the country. Therefore, route num­ber I-86 is recommended to replace I-80N since the existing I-86 is only 45.1 miles in length and is located only in Connecticut and Massachusetts. If it is desired not to use the same number on two widely separated sections of Interstate, this route could be numbered I-11 or I-13.
In addition to the above numbered items, other recent changes have been made in Interstate route numbers, mainly in Pennsylvania. As mentioned in Item #14, Ohio has renumbered I-80S as I-76. This same change in I-80S was accomplished by Pennsylvania which also has been given recent approval by AASHO and FHWA to renumber I-81E as I-380.
With the implementation of the above recommendations and the pre­viously approved changes in route numbers in Ohio, Pennsylvania and New Jersey, cardinal initials would be eliminated from all Interstate routes and it is believed that traffic operation in various areas would be greatly improved.
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