The route of I-670 was originally designated as I-70N between I-70 at Valleyview (Exit 96) and Interstate 70A in Downtown Columbus. I-70A formed a loop along the Columbus Innerbelt utilizing SR 315 to the west, what is now I-670 to the north, and I-71 to the east. I-70N and I-70A were eliminated by AASHTO on November 10, 1973. The same actions designated I-670 from I-70 at Valleyview east to Interstate 71, northeast of Downtown.
The initial stretch of I-670 freeway opened to traffic was the portion between SR 315 and U.S. 23 north of Downtown Columbus in 1961. This portion was signed as part of Interstate 71 from 1962 onward. It was extended east to the I-71 freeway leading north in 1966. I-71 was dropped from the I-670 alignment in 1976.2
Delays for construction of I-670 west of SR 315 and east of Interstate 71 were complicated not only by funding issues, but also changes in environmental regulations. Work was to commence after the 1976 opening of the I-70/71 interchange southeast of Downtown. However a 1970 environmental shift in policy prevented the relocation of the Scotio River, a piece of the Interstate 670 overall project. The actions of the National Environmental Protection Act curtailed the project and forced planners to redesign the highway from scratch in 1978. From then until 1983, up to six alternatives were considered in conjunction with new environmental review processes. The final alignment was chose in 1984.1
Additional funding shortfalls arose in the late 1980s, curtailing the forward progress of the highway in conjunction with the overall complex design. It was not until 1993 that the first of the original 15 projects associated with Interstate 670 opened to traffic. By 1996 a financial recommitment by the City of Columbus and state transportation officials was agreed upon to countermand additional funding deficits. The agreement led for ODOT to take over construction and funding of Interstate 670 west of Neil Avenue and for the City of Columbus to cover the alignment east of Neil Avenue. The September 2003 opening of the aforementioned projects culminate the final two projects of the original 15 for Interstate 670. Additionally the alignment from I-70 to Grandview Avenue was reconstructed between June 2002 and July 2003.1
Coinciding with work on the final segments of Interstate 670, the older portion underwent extensive reconstruction. On March 30, 2002, I-670 between Third Street and Neil Avenue closed for 18 months for rehabilitation and expansion. The closure coincided with new construction of I-670 between SR 315 and Neil Avenue, an overall $75 million project. Included were aesthetic improvements such as iron fencing and decorative lighting.1 On September 19, 2003, I-670 officially opened to traffic and completing the Ohio Interstate system.3,4 AASHTO officially approved Interstate 670 on May 14, 2004, with concurrence by the Federal Highway Administration obtained on May 24, 2004.