27 CAR § 95-104. Interchange spacing

(a) The spacing of adjacent interchanges has a pronounced effect on the operation of freeways. (b) As a rule of thumb, the minimum interchange spacing is one (1) mile in urban areas as measured from the intersecting crossroads. (c) More space is generally required for freeway-to-freeway interchanges due to their larger footprint and higher ramp volumes. (d) Proposed interchanges spaced less than one (1) mile in urban areas may still be considered with appropriate geometric designs, i.e., collector-distributor roads or braided ramps. (e) In rural areas, the minimum interchange spacing is three (3) miles for interstates and two (2) miles for noninterstate freeways as measured from the intersecting crossroads.