When converting an existing two-lane roadway to a four-way divided facility, the Federal Highway Administration (FHWA) allows existing alignments to remain in place. Specifically,

the new roadbed will be constructed to full current standards.

When the existing lanes are converted to one-way operations, no changes are required to the horizontal or vertical alignment of the existing road as long as it meets 3R criteria described in .

Other features such as signing, roadside hardware, and safety end treatments, should meet current standards. Existing structures with substandard widths on the existing lanes may remain if that width meets minimum 3R requirements for multi-lane facilities.

Transitions for opening and closing passing lanes on Super 2 highways is discussed in . Transitions for speed change lanes are discussed in .