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.

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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 carraigeway. 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.

When an undivided freeway has four lanes, it is known as a super-4, though these are an oddity as most multi-lane freeways are divided, due to potential accidents from high-speed traffic crossing to the opposing side. Highway 27 directly north of Highway 401 in Toronto, Ontario is an example of a super-4 freeway by this definition, as it has four lanes of undivided traffic, and is fully controlled-access with interchanges and service roads to provide access to property in the area.

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 formerly 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 Courtright. The remaining sections of Highway 40 are super-2 expressways. Other super-4 expressways include the Hanlon Parkway in Guelph and the 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 4-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 4-lane divided expressways.

List of two-lane freeways

Australia

New Zealand

Europe

United Kingdom

South Africa

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

South Korea

The 88 Olympic Expressway, Route 12, is a two-lane limited access tollway for 144 of its 183 kilometers, between exits 14 (Danyang) and 26 (East Dongguryeong). It is fully integrated into South Korea's ticketed tollway system. This section is to be widened to four lanes by 2015.

Indonesia

Japan

While most expressways in Japan are 4-lane divided expressways with median barriers, some expressways in rural areas are 2-lane expressways, such as some sections of the Hokkaidō Expressway. The 2-lane expressways in Japan are built in the same manner as the ordinary 4-lane expressways with grade-separated interchanges and full access control, allowing future conversions to full 4-lane divided expressways.[3]

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.[4] 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 (Kempas Highway) and Shapadu (North Klang Straits Bypass).

The first true two-lane expressway with full access control is the section of the Senai-Desaru Expressway between Cahaya Baru and Penawar.[5]

North America

Canada

Mexico

United States

Arkansas
California
Connecticut
Florida
Kansas
Kentucky
Louisiana
Maine
Maryland
Massachusetts
Michigan
Minnesota
New Hampshire
New Jersey
New York
North Carolina
Ohio
Oklahoma
Oregon
Pennsylvania
Rhode Island
Texas
Utah
Vermont
Virginia
Washington
West Virginia
Wisconsin

Notes