2+1 road is a specific category of three-lane
road
A road is a linear way for the conveyance of traffic that mostly has an improved surface for use by vehicles (motorized and non-motorized) and pedestrians. Unlike streets, the main function of roads is transportation.
There are many types of ...
, consisting of two lanes in one direction and one lane in the other, alternating every few kilometres, and usually separated with a steel
cable barrier
A cable barrier, sometimes referred to as guard cable or wire rope safety barrier (WRSB), is a type of roadside or median safety traffic barrier/guard rail. It consists of steel wire ropes mounted on weak posts. As is the case with any roadside b ...
. The second lane allows faster-moving traffic to
overtake slower vehicles at regular intervals. Traditional roads of at least width can be converted to 2+1 roads and reach near-
motorway
A controlled-access highway is a type of highway that has been designed for high-speed vehicular traffic, with all traffic flow—ingress and egress—regulated. Common English terms are freeway, motorway and expressway. Other similar terms i ...
safety levels at a much lower cost than an actual conversion to motorway or
dual carriageway
A dual carriageway ( BE) or divided highway ( AE) is a class of highway with carriageways for traffic travelling in opposite directions separated by a central reservation (BrE) or median (AmE). Roads with two or more carriageways which are ...
.
Sometimes, during freeway reconstruction, a
barrier transfer machine
A barrier transfer machine, also known as zipper machine or road zipper, is a type heavy vehicle that is used to transfer concrete lane dividers, such as jersey barriers, which are used to relieve traffic congestion during rush hours. Many oth ...
will be used on one half of the freeway while the other is being reconstructed.
A similar concept is utilized with 3-lane setups where 2 lanes have right of way, and the opposing side has to yield to the oncoming side on major highways that are mostly 2 lanes, of which those are more common.
By country
Estonia
The construction of 2+1 roads in Estonia first started in autumn 2016, when a contract for a reconstruction of a 9 kilometre section of the
national road 4 between
Ääsmäe
Ääsmäe is a settlement in Saue Parish, Harju County in northern Estonia.
Ääsmäe Manor
The manor in Ääsmäe traces its origins to 1574, when king John III of Sweden presented the estate as a gift to his secretary Johann Berends. The prese ...
and
Kohatu
Kohatu is a village in Saue Parish, Harju County, Estonia. (retrieved 27 July 2021) It borders Metsanurga village to the north, Mõnuste village to the west, Kernu and Kirikla villages to the south and Rapla County to the east. The territory ...
into a 2+1 road was signed.
The road is being reconstructed as a 2+1 road, equipped with barriers along the entire length.
Also there are several sections of the
national road 2 between
Põltsamaa
Põltsamaa (german: Oberpahlen) is a town in Põltsamaa Parish, Jõgeva County, Estonia. The town is situated on the Põltsamaa River, and features a 13th-century castle.
Gallery
Põltsamaa Jõgi.jpg, Põltsamaa River
Põltsamaa Vabadussõja m ...
and
Tartu
Tartu is the second largest city in Estonia after the Northern European country's political and financial capital, Tallinn. Tartu has a population of 91,407 (as of 2021). It is southeast of Tallinn and 245 kilometres (152 miles) northeast of ...
planned for a conversion into 2+1 road. The first of them (
Annikvere-
Neanurme) was opened in November 2017. The speed limits are during summer and during winter.
Finland
![Orivesi Jyväskyläntie](https://upload.wikimedia.org/wikipedia/commons/c/cb/Orivesi_Jyv%C3%A4skyl%C3%A4ntie.jpg)
The first 2+1 road in Finland was opened in 1991 on
Finnish national road 4 , sv, Riksfyran; fi, Lahdenväylä; sv, Lahtisleden
, maint = the Finnish Transport Agency
, map = Finland national road 4.png
, length_km = 1295
, length_round =
, length_ref =
, established = 1938
, direction_a =
, terminus_a = Helsi ...
between
Järvenpää
Järvenpää (; sv, Träskända) is a town and municipality in Finland. It is located on the Helsinki–Riihimäki railway track in Uusimaa region, some north of Helsinki. Neighbouring municipalities are Tuusula, Sipoo and Mäntsälä. People ...
and
Mäntsälä, which later was upgraded to a motorway. Since then, numerous 2+1 roads have been built as part of the national road network. They resemble motorways in that they are typically, although not always,
limited-access road
A limited-access road, known by various terms worldwide, including limited-access highway, dual-carriageway, expressway, limited access freeway, and partial controlled access highway, is a highway or arterial road for high-speed traffic which ...
s and have no at-grade interchanges. In the mid-1990s, 2+1 roads with traffic separators were introduced; these are effective in preventing head-on collisions, and approaching the safety of motorways. In 2006, there were 440 km of 2+1 roads, e.g. along
road 3 and
road 4. However, they weren't that much of a panacea: interchanges made the roads much more expensive than planned and confusing to drivers. Thus, new construction halted and only 2+2 roads with traffic separators were built. These are however more expensive and require more widening of the road.
Germany
![B 54 bei Steinfurt](https://upload.wikimedia.org/wikipedia/commons/8/84/B_54_bei_Steinfurt.jpg)
The "2+1-System" refers to expressways with three lanes on a single carriageway where bypassing on the lane of the opposite direction is prohibited so that speed restriction is not required to increase safety. These expressways are grade-separated with a design speed of and the side of two lanes (allowing to bypass lower speed vehicles) alternates about every 1.5 to 2 kilometres. In hilly parts, the uphill direction is usually the one with two lanes to allow overtaking of heavy, slow vehicles. In many cases, there is no median barrier or it consists of concrete blocks – additional safety measures are mostly needed near the end of the two lane section where some motorists tend to pull in very late so that a longer no-traffic section needs to be inserted on the middle lane.
After some good experiences with test roads the system has been used often in places where the amount of traffic does not justify construction of a
dual carriageway
A dual carriageway ( BE) or divided highway ( AE) is a class of highway with carriageways for traffic travelling in opposite directions separated by a central reservation (BrE) or median (AmE). Roads with two or more carriageways which are ...
expressway but remote rural areas should be connected to major towns with a high speed road. Existing examples are
B 1,
B 4 near Uelzen,
B 16,
B 20,
B 31n near Stockach (),
B 33,
B 54,
B 56n,
B 67 between Bocholt and Rhede,
B 72,
B 210,
B 300,
B 482, and parts of the
A 98.
Israel
In
Israel
Israel (; he, יִשְׂרָאֵל, ; ar, إِسْرَائِيل, ), officially the State of Israel ( he, מְדִינַת יִשְׂרָאֵל, label=none, translit=Medīnat Yīsrāʾēl; ), is a country in Western Asia. It is situated ...
, route 437 is a 2+1 from Hizme Junction to Adam Junction. The road descends before ascending, and whichever direction is uphill is the one with two lanes.
Ireland
In the
Republic of Ireland
Ireland ( ga, Éire ), also known as the Republic of Ireland (), is a country in north-western Europe consisting of 26 of the 32 counties of the island of Ireland. The capital and largest city is Dublin, on the eastern side of the island. A ...
, a 2+1 road was tried on a short section of the
N20 near
Mallow,
County Cork
County Cork ( ga, Contae Chorcaí) is the largest and the southernmost county of Ireland, named after the city of Cork, the state's second-largest city. It is in the province of Munster and the Southern Region. Its largest market towns are ...
and the
N2 near
Castleblayney
Castleblayney (; ) is a town in County Monaghan, Ireland. The town had a population of 3,607 as of the 2016 census. Castleblayney is near the border with County Armagh in Northern Ireland, and lies on the N2 road from Dublin to Derry and Let ...
,
County Monaghan
County Monaghan ( ; ga, Contae Mhuineacháin) is a county in Ireland. It is in the province of Ulster and is part of Border strategic planning area of the Northern and Western Region. It is named after the town of Monaghan. Monaghan County Cou ...
. Following the pilot, the
National Roads Authority
The National Roads Authority (NRA) ( ga, An tÚdarás um Bóithre Náisiúnta) was a state body in Ireland, responsible for the national road network. The NRA was established as part of the Roads Act 1993 and commenced operations on 23 December ...
announced in July 2007 that 2+1 roads were unsuitable and that new lower capacity trunk routes would instead be built as
2+2 road
A 2+2 road is a specific type of dual-carriageway that exists primarily in Ireland, Sweden, Estonia and Finland, consisting of two lanes in each direction separated by a steel cable barrier.
These roads do not have hard shoulders and therefore ...
s (officially known as "Type 2 Dual Carriageways") – at grade
dual-carriageways
A dual carriageway (British English, BE) or divided highway (American English, AE) is a class of highway with Carriageway, carriageways for traffic travelling in opposite directions separated by a central reservation (BrE) or median (AmE). ...
with a narrow median and no hard shoulder.
Lithuania
The first rural 2+1 road section finished in Lithuania was a short 1.5 km road section of A11 between
Šiauliai
Šiauliai (; bat-smg, Šiaulē; german: Schaulen, ) is the fourth largest city in Lithuania, with a population of 107,086. From 1994 to 2010 it was the capital of Šiauliai County.
Names
Šiauliai is referred to by various names in different l ...
and the junction with the A18 road (
Šiauliai
Šiauliai (; bat-smg, Šiaulē; german: Schaulen, ) is the fourth largest city in Lithuania, with a population of 107,086. From 1994 to 2010 it was the capital of Šiauliai County.
Names
Šiauliai is referred to by various names in different l ...
Bypass). It was opened in late 2017.
All 1+1 sections of
Via Baltica
European route E 67 is an E-road running from Prague in the Czech Republic to Estonia and by ferry to Finland. It goes via Prague, Wrocław, Warsaw, Kaunas, Panevėžys, Riga, Tallinn, Helsinki.
The route is known as the Via Baltica ...
north of
Kaunas
Kaunas (; ; also see other names) is the second-largest city in Lithuania after Vilnius and an important centre of Lithuanian economic, academic, and cultural life. Kaunas was the largest city and the centre of a county in the Duchy of Trakai ...
up to the
Latvia
Latvia ( or ; lv, Latvija ; ltg, Latveja; liv, Leţmō), officially the Republic of Latvia ( lv, Latvijas Republika, links=no, ltg, Latvejas Republika, links=no, liv, Leţmō Vabāmō, links=no), is a country in the Baltic region of ...
n border are planned to be converted to 2+1 by 2035. The first section, the A17 road or
Panevėžys
Panevėžys (; Latin: ''Panevezen''; pl, Poniewież; yi, פּאָנעװעזש, ''Ponevezh''; see also other names) is the fifth largest city in Lithuania. As of 2011, it occupied with 113,653 inhabitants. As defined by Eurostat, the population ...
Bypass was constructed in 2019. Work took place in stages. The first 10 km section between junctions with the A8 and the A9 was finished in summer 2018. The remaining section up to the A10 road was completed in 2019.
All planned 2+1 sections will be equipped with barriers.
New Zealand
In New Zealand, there are few 2+1 roads, although regular isolated 'passing lanes' exist frequently throughout the country, mainly in heavily trafficked areas and on hills. A trial of a 2+1 road with a wire-rope median barrier was undertaken on SH1 between Longswamp and Rangiriri south of Auckland, and there are plans to introduce more 2+1 roads. NZ research also investigated the design and operational effects of 2+1 roads to establish the most appropriate configurations for the country.
Portugal
In Portugal, there are plenty of 2+1 roads. Almost every national road in the country has a 2+1 profile, but the biggest part is located in the north because of the hills (for example, in
Beira Baixa, or
Viseu
Viseu () is a city and municipality in the Centro Region of Portugal and the capital of the district of the same name, with a population of 100,000 inhabitants, and center of the Viseu Dão Lafões intermunipical community, with 267,633 inhabita ...
). One example of this is the N2 road, which goes from
Faro (
Algarve
The Algarve (, , ; from ) is the southernmost NUTS II region of continental Portugal. It has an area of with 467,495 permanent inhabitants and incorporates 16 municipalities ( ''concelhos'' or ''municípios'' in Portuguese).
The region has it ...
) to
Chaves. Also, this type of road isn't frequently used on parts of roads that have a village near, except in the
Lisbon District
Lisbon District ( pt, Distrito de Lisboa, ) is a district located along the western coast of Portugal. The district capital is the city of Lisbon, which is also the national capital. From its creation until 1926, it included the area of the cur ...
where most of them have that profile. In Portugal, there are 4 (major) types of roads: a national road (N) which sometimes contains the 2+1 profile, a complementary route (IC), which always contains the 2+1 profile, except inside villages, a principal route (IP) which either contains the 2+1 profile (with the IC profile) or the 2+2 profile (with the A profile) and a highway (A) which has its own profiles, like 2+2, 3+3 or 4+4.
Romania
![2+1 road on the DN7, Olt Valley section, Romania](https://upload.wikimedia.org/wikipedia/commons/d/d3/2%2B1_road_on_the_DN7%2C_Olt_Valley_section%2C_Romania.jpg)
The 2+1 road format in Romania often refers to sections, usually on steep inclines, where there is another lane, designed to be used by slow vehicles to avoid congestion when going uphill.
The first 2+1 "alternative" road opened between
Lazaret
A lazaretto or lazaret (from it, lazzaretto a diminutive form of the Italian word for beggar cf. lazzaro) is a quarantine station for maritime travellers. Lazarets can be ships permanently at anchor, isolated islands, or mainland buildings. ...
and
Turnul Spart in 2018 on the Olt Valley section of the
DN7
DN7 ( ro, Drumul Național 7) is a national road in Romania which links Bucharest with the Banat region, in western Romania, and further to the eastern European capitals Budapest and Belgrade via the border with Hungary at Nădlac. It is a high- ...
. This section lacks cable barriers, but provisions have been made to install one, if needed. The next 2+1 road section to open will be between
Sinești and
Movilița on the DN2. The
DN2 is currently configured as a 13 m wide road with emergency lanes, in the same style as 13 m wide roads in Sweden, however, drivers improperly use the emergency lanes, leading to the current high number of crashes.
Once the roadworks will be completed, the 2+1 road is supposed to reduce the number of crashes, but it will lack the essential cable barrier. This is because the only cable barrier installed in Romania, at
Afumați on the same DN2 was damaged because the lanes were too close to it and a truck hit it, but instead, the Romanian Roads Administration (CNADNR) blamed the "unsafety" of the barrier.
Russia
Some federal roads use the 2+1 design. The length of overtaking sections is 400 to 3,000 metres. Unlike in Western Europe, the majority of Russian 2+1 roads are not equipped with barriers. The most well-known example of a 2+1 is the M-10 road section between Tver and Novgorod oblast. This 2+1 is particularly popular in Krasnodar Kraj and Sakhalin Island.
Sweden
In Sweden, many roads have been built, especially in the period 1955–1980. These have two lanes, and two shoulders, in the beginning planned as emergency strip, due to the relative unreliability of cars of that period.
Around 1990, the idea emerged to build fences in the middle of them and to have 2+1 lanes. This was thought to be a cheap way of increasing traffic safety since these roads had a bad safety record of many head-on collisions at high speeds. Some people were, for example, overtaking against meeting traffic assuming meeting cars would go to the side. The roads are a little narrow for 3 lanes, but trials were carried out on a few roads. It turned out that not only did safety improve, but it was also easier to overtake than before as the 2-lane sections provide safe overtaking opportunities. After the year 2000, more than of roads in Sweden have been converted from wide ordinary roads into 2+1-road, all with barriers.
Until around 2005, the roads had the original speed limit in use on most highways. As a result of this, many people drove at 90 km/h at 1-lane parts but at 2-lane parts, this being the speed limit on motorways. The speed limit has now been changed to with a notably smoother traffic flow. There is a problem that some people want to overtake as many slow cars as possible in the two-lane sections, sometimes with small margins at the end of the section.
United Kingdom
In the UK, 2+1 roads are known as 'Wide single 2+1 roads'. According to the Design Manual for Roads and Bridges, they should only be used on rural all-purpose single carriageways. The overtaking lane sections can be between 800 metres and 1500 metres. This is because this length allows for cars to overtake, but does not cause frustration for drivers on single-lane sections. It is recommended to use hatching with double solid lines to separate traffic flows to stop single-lane traffic from using the oncoming overtaking lane. 2+1 roads can also be used for climbing lanes, to allow slower vehicles to be overtaken by other vehicles when travelling uphill on a single carriageway. They should be used where the road is longer than 500 metres at a gradient of 2%.
United States
![State route 77 in the salt river canyon, arizona](https://upload.wikimedia.org/wikipedia/commons/4/4c/State_route_77_in_the_salt_river_canyon%2C_arizona.jpg)
The United States has 2+1 roads in states such as
California
California is a U.S. state, state in the Western United States, located along the West Coast of the United States, Pacific Coast. With nearly 39.2million residents across a total area of approximately , it is the List of states and territori ...
,
New Hampshire
New Hampshire is a U.S. state, state in the New England region of the northeastern United States. It is bordered by Massachusetts to the south, Vermont to the west, Maine and the Gulf of Maine to the east, and the Canadian province of Quebec t ...
and
Missouri
Missouri is a U.S. state, state in the Midwestern United States, Midwestern region of the United States. Ranking List of U.S. states and territories by area, 21st in land area, it is bordered by eight states (tied for the most with Tennessee ...
. The most prominent example is
Interstate 93
Interstate 93 (I-93) is an Interstate Highway in the New England states of Massachusetts, New Hampshire, and Vermont in the United States. Spanning approximately along a north–south axis, it is one of three primary Interstate Highways ...
in
Franconia Notch State Park
Franconia Notch State Park is a public recreation area and nature preserve that straddles of Interstate 93 as it passes through Franconia Notch, a mountain pass between the Kinsman Range and Franconia Range in the White Mountains of northe ...
(before dropping down to a single lane in each direction, plus a steel divider). The mode is not unknown in the United States off Interstate roads, including for example
California State Route 1
State Route 1 (SR 1) is a major north–south state highway that runs along most of the Pacific coastline of the U.S. state of California. At , it is the longest state route in California, and the second-longest in the US after Monta ...
between
Malibu and
Oxnard
Oxnard () is a city in Ventura County, California, United States. On California's South Coast, it is the most populous city in Ventura County and the 22nd-most-populous city in California. Incorporated in 1903, Oxnard lies approximately west ...
,
Arizona State Route 77
State Route 77 (or SR 77) is a state highway in Arizona that traverses much of the state's length, stretching from its northern terminus at the boundary of the Navajo Nation north of Holbrook to its junction with I-10 in Tucson.
Route descriptio ...
north of
Oracle
An oracle is a person or agency considered to provide wise and insightful counsel or prophetic predictions, most notably including precognition of the future, inspired by deities. As such, it is a form of divination.
Description
The word '' ...
and the section of
Missouri Route 5
Missouri Route 5 is the longest state highway in Missouri and the only Missouri state highway to traverse the entire state. It is part of a three state, 650 mile highway 5. To the north, it continues into Iowa as Iowa Highway 5 and to the south ...
between the towns of
Lebanon
Lebanon ( , ar, لُبْنَان, translit=lubnān, ), officially the Republic of Lebanon () or the Lebanese Republic, is a country in Western Asia. It is located between Syria to the north and east and Israel to the south, while Cyprus li ...
and
Camdenton. In the United States, this term is not used and roads that would be in a configuration that could be described as 2+1 usually have an extra added climbing lane on steep grades for trucks and slow vehicles to climb or are dropping or expanding to 2 or 4 lanes respectively.
These roads also exist in
Texas
Texas (, ; Spanish language, Spanish: ''Texas'', ''Tejas'') is a state in the South Central United States, South Central region of the United States. At 268,596 square miles (695,662 km2), and with more than 29.1 million residents in 2 ...
, called "
Super 2", as that term has more than one definition.
In the 1950s,
New York
New York most commonly refers to:
* New York City, the most populous city in the United States, located in the state of New York
* New York (state), a state in the northeastern United States
New York may also refer to:
Film and television
* '' ...
state built many highways which totalled 3 lanes wide, with traffic moving in either direction permitted to use the center lane for passing. After less than ten years of
a frighteningly high head-on collision rate, all were re-striped into either two wide lanes, or a one-direction passing lane, or alternating between the two systems.
Elsewhere
![9382Southern Tagalog Arterial Road 12](https://upload.wikimedia.org/wikipedia/commons/a/aa/9382Southern_Tagalog_Arterial_Road_12.jpg)
Divided 2+1 roads are rare outside of Europe and the United States, though they are seen in a few places, such as
Australia
Australia, officially the Commonwealth of Australia, is a Sovereign state, sovereign country comprising the mainland of the Australia (continent), Australian continent, the island of Tasmania, and numerous List of islands of Australia, sma ...
and the Canadian provinces of
Ontario
Ontario ( ; ) is one of the thirteen provinces and territories of Canada.Ontario is located in the geographic eastern half of Canada, but it has historically and politically been considered to be part of Central Canada. Located in Central Ca ...
and
Quebec
Quebec ( ; )According to the Canadian government, ''Québec'' (with the acute accent) is the official name in Canadian French and ''Quebec'' (without the accent) is the province's official name in Canadian English is one of the thirtee ...
. In Japan, a 2+1 road was implemented in the northern island of Hokkaido.
Kazunori Munehiro (2015), Performance Evaluation of 2+1 Lane Highway in Hokkaido, Japan: Case Study of Saraki-tomanai Road
5th International Symposium on Highway Geometric Design, Vancouver, Canada.
See also
*Reversible lane
A reversible lane (British English: tidal flow) is a lane in which traffic may travel in either direction, depending on certain conditions. Typically, it is meant to improve traffic flow during rush hours, by having overhead traffic lights and li ...
*Road diet
A road diet, also called a lane reduction, road rechannelization, or road conversion is a technique in transportation planning whereby the number of travel lanes and/or effective width of the road is reduced in order to achieve systemic improveme ...
*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 ris ...
* Super 2
*2-1 road
A 2-1 road (2-minus-1 road) is a type of road with extra wide shoulders, and a smaller single two-way lane in the middle for vehicles. The shoulders are to be used by pedestrians and cyclists, and if necessary by meeting vehicles. The purpose o ...
*Dual carriageway
A dual carriageway ( BE) or divided highway ( AE) is a class of highway with carriageways for traffic travelling in opposite directions separated by a central reservation (BrE) or median (AmE). Roads with two or more carriageways which are ...
References
External links
National Roads Authority
Interim Advice Note on Road Link Design for 2+1 roads
(PDF
Portable Document Format (PDF), standardized as ISO 32000, is a file format developed by Adobe in 1992 to present documents, including text formatting and images, in a manner independent of application software, hardware, and operating systems. ...
4.7 MB)
Major Road Schemes in Ireland 2008 update
NCHRP Research Synthesis #275 on 2+1 Roadway Design Standards
{{DEFAULTSORT:2 1 Road
Road surface markings
Types of roads
Articles containing video clips