Two-lane expressway


A two-lane expressway or two-lane freeway is an expressway or freeway 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; a former example is some sections of U.S. Route 101 in northern California.
In Europe, the concept of express road, is related to road which are classed between a motorway and an ordinary road. This concept is recognized both by European union law and by UNECE treaty. This type of road is not very standardized, and its geometry may vary from country to country or within a same country. These roads are usually, but not always, reserved for motorized vehicles, and accessible with limited-access roads. Some European union regulation considers the high-quality roads are roads "which play an important role in long-distance freight and passenger traffic, integrate the main urban and economic centres, interconnect with other transport modes and link mountainous, remote, landlocked and peripheral NUTS 2 regions to central regions of the Union». According to this same regulation «High-quality roads shall be specially designed and built for motor traffic, and shall be either motorways, express roads or conventional strategic roads."

Justification

Two-lane freeways are usually built as a temporary solution due to lack of funds, as an environmental compromise or as a way to overcome problems constrained from highway reconstruction when there are four lanes or more. If the road is widened, the existing road is typically allocated to traffic going in one direction, and the lanes for the other direction are built as a whole new roadbed adjacent to the existing one. When upgraded in this manner, the road becomes a typical freeway. Many two-lane freeways are built so that when the road is upgraded to a proper divided freeway, the existing overpasses and ramps do not need reconstruction.
A super-2 expressway is a high-speed surface road with at-grade intersections, depending on the common usage of the term expressway in the area. By this definition, Super-2s can be considered the first stage of project which is expected to become a full freeway, with the transportation authority owning the land necessary for the future adjacent carriageway. At-grade intersections exist but there is sufficient land to replace them with interchanges. In some US states, a super-2 expressway is simply referred to as a super-2, regardless of whether it is fully controlled-access or not. Highway 410 in Ontario was originally a super-2 before being upgraded to a full freeway. Similarly, most of Highway 102 in Nova Scotia was a super-2 for three decades before being upgraded. Many super-2 expressways are simply just short transitional segments between surface street and four-lane divided freeways.
A super-4 expressway is a multi-lane divided highway with at-grade intersections, although the highway will become a full controlled-access freeway if the intersections are replaced with interchanges. A super-4 may have been a super-2 that has been twinned, although such instances of super-4 intermediaries are rare as super-2s are often upgraded right away to full freeways. Highway 40 in Ontario is a super-4 expressway between Highway 402 and Wellington St., and from Indian Rd to Rokeby Line. The remaining sections of Highway 40 are super-2 expressways. Other super-4 expressways include the Hanlon Parkway in Guelph and Black Creek Drive in Toronto, both which have sufficient right of way to allow for interchanges and overpasses to replace the at-grade crossings.
When a super-2 expressway is converted to a four-lane divided freeway, conversion artifacts such as double yellow lines, or broken yellow lines in passing zones are usually cleanly bestowed in favor of more consistent road marking for four-lane divided expressways.

List of two-lane freeways

Argentina

While most expressways in Japan are four-lane divided expressways with median barriers, some expressways in rural areas are two-lane expressways, such as some sections of the Hokkaidō Expressway. The two-lane expressways in Japan are built in the same manner as the ordinary four-lane expressways with grade-separated interchanges and full access control, allowing future conversions to full four-lane divided expressways.

Malaysia

The two-lane expressway is not a new concept in Malaysia, as the Kuala Lumpur–Karak Expressway was initially a two-lane toll expressway before being upgraded to a full expressway in 1997. While the full four-lane divided toll expressways are more favored in recent years due to their higher traffic capacity, a few two-lane expressways do exist, such as the Kempas Highway and the North Klang Straits Bypass. These expressways, however, only have partial access control with at-grade intersections commonly available like most other federal and state roads. Nevertheless, these two-lane highways are still classified as "two-lane expressways" as they are maintained by highway concessionaires, namely PLUS Expressways Berhad and Shapadu.
Meanwhile, the South Klang Valley Expressway at Teluk Panglima Garang is a two-lane carriageway making it the first true two-lane expressway in Klang Valley and the second in Malaysia.
The first true two-lane expressway with full access control is the section of the Senai–Desaru Expressway between Cahaya Baru and Penawar.

Mexico

;Motorways
; Expressways
Some sections of two-lane freeway can be found on the N1 and the N2 highways.

South Korea

753 of 1,225 kilometers were two-lane expressway in 1978. After 1992, South Korean Government planned to widen all two-lane expressways into four-lane. All expressways except 88 Olympic Expressway has been widened before 2004. 88 Olympic Expressway was the last two-lane limited access tollway of South Korea, for 144 of its 183 kilometers, between exits 14 and 26. Although a service rating of two-lane section was poor, still they were fully integrated into South Korea's ticketed tollway system. No two-lane expressway has been in South Korea after 22 December 2015, since all expressways are widened to four-lane.

United Kingdom

Arkansas

The section from Yen Bai City to Lao Cai City of the Hanoi-Lao Cai Expressway is two-laned.