Details of the 1957 urban additions (216 mi total):
- urban connections
- 12.5~ mi Chicago: assumed to be 494 (1962 map)
- 8 mi Philadelphia: Phillyroads says it was 695
- 6 mi St. Louis: assumed to be 244 south of 44 (1957 map)
- Washington:
- 1 mi Kansas City: assumed to be one of the east-west legs of the downtown loop (1957 map)
- 11 mi Louisville: 264 shown west of 65 on 1962 KY official
- Omaha:
- 8.5 mi Duluth: assumed to be 35 north of 535 to 68th Avenue, but may have been only part
- belt routes
- 60 mi Cincinnati: all of 275 shown on 1962 OH official
- 7 mi Louisville: assumed to be 265 in Indiana
- 28 mi San Diego: [1] says AASHO approved 805 in 1958
- 4 mi Akron: Kurumi says 277 existed by 1958 (as 480, but was this a final number? was the original route longer?)
- 4.5 mi Springfield-Holyoke: 391 is the only possibility, despite not being a belt
- 23 mi Dayton: all of 675 shown on 1962 OH official; mileage is assumed because 3.5 mi was added in 1968
- 20 mi Hartford: Kurumi says it was 291 west of 91 (east of 91 added 1968)
- 12 mi Oklahoma City: 240 east of 35 shown on 1961 OK official
- 6.5 mi Syracuse: 481 south of 690 shown on 1959 numbering map
- 35 mi Jacksonville: assumed to be 295 west of 95
- Scranton: huh?
- 29 mi Salt Lake City: 215 and 415 confirmed to exist in full by 1962 (p. 11)
- 13 mi Sacramento: [2] says AASHO approved 880 in 1958
This adds to 289. WTF??