Two-lane Expressway

A two-lane expressway is an expressway with only one lane in each direction, and usually no median barrier. It may be built that way because of constraints, or may be intended for expansion once traffic volumes rise. The term super two is often used by roadgeeks for this type of road, but traffic engineers use that term for a high-quality surface road. Most of these roads are not tolled.

A somewhat related concept is a four-lane undivided expressway. This is much rarer; an example is some sections of U.S. Route 101 in northern California.