CARxR 1.09: Highway Numbering: Interstate Highways

In this episode, we continue our exploration of numbering of state highways by turning our attention to the Interstate Highway system. This system, started in 1956, uses the red, white, and blue shields. It is the third episode in a four part miniseries on highway numbers in California. In this episode we talk about the history of the Interstate Highway system, how the Interstate Highways are numbered, the history of California’s chargable interstates (i.e., highways that counted towards the federal 42,500 mile limit), the history of California’s non-chargeable interstates, some interstate submissions that were never approved, and we opine about some of the most common questions about California interstates.

There is no interview. We’re going to move the interview segments into separate bonus episodes, owing to the difficulty of obtaining and scheduling the interviews.

The remaining episode in this miniseries will explore the numbering of and the history of California’s signed county route system.

Here’s the link to the show:

And here’s the link on Spotify for Podcasters:

Here are some relevant links (I may edit this to add more links in later):

• California Highways:
  • Interstate Highway Types and the History of California’s Interstates
    • Control Cities
    • Chargeable and Non-Chargeable Interstates
    • Interstates Turn 50: California Celebrates 50 Years of the Interstate Highway System
    • Interstates Turn 50: History of Interstates in California
    • Interstates Turn 50: Timeline
    • Interstates Turn 50: Innovations
    • Interstates Turn 50: Additional Historic Photos
  • Highway Numbering: Numbering of Eisenhower Interstate Numbered Routes
• Gribblenation:
  • Establishing the numbering conventions of California’s chargeable Interstates
  • Interstate 5; Southern San Diego County to California State Route 99 in Wheeler Ridge
  • Interstate 5; the West Side Freeway
  • Interstate 505; a trace of Interstate 5W
  • California State Route 51; failed Interstate 80 on the Capitol City Freeway, the I–80 Business Loop, and former US 40/99E
  • Interstate 80 west over the Carquinez Bridge to the San Francisco-Oakland Bay Bridge
  • Legacy California State Route 17; CA 13 (i), CA 17, the Nimitz Freeway, I–880, the Richmond-San Rafael Bridge, and I–580
  • Interstate 580 from Interstate 5 west to California State Route 13
  • Interstate 980
  • Interstate 238; the Interstate numbering abomination carved out of an otherwise mundane State Highway
• AARoads:
  • Interstate 5
  • Interstate 8
  • Interstate 80
  • Business Loop I–80/Interstate 305/California 51 in Sacramento
  • I–305
  • Interstate 10
  • Interstate 405
  • Interstate 40
  • Interstate 580
  • Interstate 980
  • California/Interstate 238
• Federal Highway Administration: The Interstate System

Episode 1.10 will conclude the numbering miniseries, and we’ll be looking at the County Sign Route system.

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