primary system
Defined in 1 dictionary — U.S. Code
United States Code
23 U.S.C. § 131 — for purposes of this section (2 versions over time)
For purposes of this section, the terms “primary system” and “Federal-aid primary system” mean the Federal-aid primary system in existence on June 1, 1991, and any highway which is not on such system but which is on the National Highway System.
23 U.S.C. § 136 — for purposes of this section (4 versions over time)
For purposes of this section, the terms “primary system” and “Federal-aid primary system” mean any highway that is on the National Highway System, which includes the Interstate Highway System.