The Not So Great Interstate 238
With its red, white and blue Interstate shield blazing a short 2.1 mile trail across a portion of the East Bay area of California south of Oakland, I-238 would appear to be like any of the similar highways of the nation’s system. But this one is a little different, and much maligned.
Why the I-238 hate? There is no Interstate 38, and therefore I-238 is an affront to the conventions of highway numbering that hold shorter auxiliary routes are numbers after their “parent” highway.
This out-of-whack designation comes to be thanks to a geographic quirk of the highway system near San Francisco, only one mainline interstate, I-80, serves the entire metro Bay Area. So there was bound to be trouble. I-80's western terminus is in San Fran after an east-west cross-country journey originating in the New Jersey Meadowlands, just outside of New York City. It crosses its final (or first, depending on your orientation) north-south mainline route, Interstate 5, in Sacramento. That leaves it to auxiliary routes of I-80 like 280, 380, 580…980, to serve the interstate needs of Bay Area drivers.
When the roadway that became I-238 was drawn up, there were no available I-x80 numbers to be had. So I-238 name was created as an extension of the nearby state road of the same number.
Take a deep dive into the numbering decision on the aptly named Indigestion 238.
AA Roads provides a full photo tour of I-238.