[[File:I-{{{2}}} (CA).svg|25x20px|link= ]] [[Interstate {{{2}}} (California)|I‑{{{2}}}]]
The Template:JctI functions similar to {{Jct|state=xx|I|nnn}}, to format U.S. Interstate highway signs and names for U.S. highways. Intended as a quick version of {Jct} only for Interstate highways, it runs at the rate of 50 roads per second, or 4x times faster than template {Jct}.
If parameter {3} is not blank then superscript "[fix JctI]" is appended as a wikilink reminding to use {Jct} instead, and listing the parameters of those roads to format.
Template:JctI operates as a co-template to {Jct}, with no additional options, and advising to use {Jct} when extra options are not supported.