Highway strip

A highway strip, road runway or road base is a section of a highway, motorway or other form of public road that is specially built to act as a runway for (mostly) military aircraft and to serve as an auxiliary military air base. These runways allow military aircraft to continue operating even if their regular air bases, some of the most vulnerable targets in any war, are degraded or destroyed.

The first highway strips were constructed near the end of World War II in Nazi Germany, where the well developed Reichsautobahn system allowed aircraft to use the motorways. During the Cold War highway strips were systematically built on both sides of the Iron Curtain, in many cases in response to the Six Day War and Operation Focus in 1967, where the Israeli Air Force in a surprise air strike disabled many of their opponents' air bases in just a few hours. Countries that have built highway strips include both West and East Germany, Singapore, North Korea, Taiwan, Sweden, Finland, Bulgaria, Switzerland (military significance), Poland, India, Pakistan and Czechoslovakia.

Design
The strips are usually 2 to 3.5 km straight sections of the highway, where any central reservation is made of crash barriers that can be removed quickly (in order to allow airplanes to use the whole width of the road), and other features of an airbase (taxiways, airport aprons) can be built. The road will need a thicker-than-normal surface and a solid concrete base. The specialized equipment of a typical airfield are stored somewhere nearby and only carried there when airfield operations start. The highway strips can be converted from motorways to airbases typically within 24 to 48 hours. The road would need to be swept to remove any debris before use by aircraft. Road runways can however also be quite small—the short runways built in the Swedish Bas 90 system are commonly only 800 m in length. The STOL-capability of the Viggen and Gripen allowed for such short runways. In the case of Finnish road airbases, the space needed for landing aircraft is reduced by means of a wire, similar to the CATOBAR system used on some aircraft carriers.

Around the world
A number of countries around the world utilise the strategy of highways constructed to double as auxiliary airbases in the event of war.

Australia
While not designed for military use, in outback Australia some sections of highway are maintained as emergency runways for use by the Royal Flying Doctor Service.

Bosnia and Herzegovina
In Glamoč, Bosnia and Herzegovina, the M15 road was used as a military airstrip. There is a clear example of how the road was widened for the needs of airplane landing.

China
In 1989 China conducted its first highway strip drills. They have since been conducted at later dates and in different areas of the country. In 2014 Chinese forces landed warplanes on a highway strip in Henan province for the first time.

Cyprus
After the Turkish invasion of Cyprus, three highway strips were built in the Greek part of Cyprus, easily recognisable by a runway centre line and markings for the touchdown zone. They also all have aircraft turning areas at either end. One is located on the A1 Limassol–Nicosia Highway (5200 m) and one near the western end of the A5 Limassol–Larnaca highway (5000 m). The third is a much smaller strip located on the A6 Limassol-Paphos highway near to Paphos International Airport.

Czechia
In Czechia, highway strips are called "the airport section of the highway" (letištní úsek dálnice (LÚD)). There are two existing highway strips. One on highway D1 (km 136.8 to 139.2) near Měřín city, 2100 m long and 25.5 m wide. It was finished in 1976 and used for exercise landings and take-offs in 1980, 1982 and 1985. The second highway strip is on highway D46 (km 1.4 to 4.2) and it is meant as backup take-off and landig runway for Vyškov airport. Many more were planned, but not built.

Estonia
During the Operation Saber Strike exercises in 2016 and 2018, A-10 Thunderbolt II aircraft from the United States Air National Guard operated from former Warsaw Pact road runways in Estonia.

Finland
In the Winter War of 1939-1940 the Finnish Air Force re-deployed its aircraft to makeshift airfields including frozen lakes to preserve them against Soviet air attack. The tactic was successful, with Soviet air raids on bases causing little damage and the vastly outnumbered Finnish aircraft scoring a high number of aerial victories.

Throughout the Cold War the Finnish Air Force maintained a network of secondary airfields including civilian airports and road bases to improve survivability and effectiveness in the event of war.

As of 2017, all aircraft in the Finnish Air Force are capable of operating from road bases.

Currently Finland conducts drills on its road bases (maantietukikohta), around once a year. In the Baana 16 exercise in 2016 the Finnish Air Force flew F/A-18C and BAE Hawk, Pilatus PC-12 and C295M aircraft from a highway in Lusi. The Finnish Air Force uses arresting cables to quickly stop F/A-18s, which were originally designed to operate from aircraft carriers. The Swedish Air Force also took part in the 2015 and 2016 exercises, flying Gripen fighters.

Germany
Germany has a number of highway strips (NLP-Str - Notlandeplätze auf Straßen, "emergency airfields on roads").

India
In India, highway strips are called Emergency Landing Facilities (ELF). ELF facilities are activated in the states of Uttar Pradesh, Rajasthan, Andhra Pradesh and union territory of Jammu and Kashmir. A total 13 locations have been chosen for development of such highway strips.


 * Yamuna Expressway: India has successfully tested its runway strip on a stretch of the Yamuna Expressway in Uttar Pradesh on 21 May 2015. It was built at a cost of ₹130 billion for its combat jets of the Indian Air Force (IAF), a first for military aviation in the country. In June 2016, the Minister of Road Transport and Highways, Nitin Gadkari announced that the government was considering developing 'Road Runways' for commercial operations as well.
 * Agra–Lucknow Expressway (Lucknow) : India successfully tested another runway strip on a stretch of the Agra Lucknow Expressway in Uttar Pradesh on 24 October 2017.
 * National Highway 925 (Barmer): On 9 September 2021, the Minister of Road Transport and Highways, Nitin Gadkari, and the Minister of Defence, Rajnath Singh, inaugurated India's first runway strip on a National Highway NH925 in Barmer, Rajasthan and, a mock emergency landing was conducted with the two ministers and the Air Chief Marshal R. K. S. Bhadauria on-board a military transport aircraft.
 * National Highway 16 (Bapatla): An Emergency Landing Facility airstrip was activated on National Highway 16 on 18 March 2024. The 4.1 km long and 33 m wide strip has been constructed by the National Highways Authority of India. Aircraft, including Sukhoi Su-30MKI, Hawk, An-32, Dornier 228, conducted landing trials on the same day.
 * National Highway 44 (Anantnag): An ELF was tested on April 2, 2023 from 03:45 to 04:30 am in Jammu and Kashmir's Anantnag district. The landing strip is 3.5 km long. Five helicopters including two Chinook, two Dhruv and one Mi-17 of IAF were part of the trial. It also included Sukhoi Su-30MKI and HAL Tejas. The landing strip construction started in 2020 at a cost of inr 1190000000.

Japan
In Hokkaido the Japan Self-Defense Forces have Kenebetsu Air Base and Yakumo Sub Base as alternative air bases.

North Korea
North Korea has established a large number of highway strips to use in case of war.

Pakistan
In Pakistan, The M-1 Motorway (Peshawar-Islamabad) and the M-2 Motorway (Islamabad-Lahore) each include two emergency runway sections of 9000 ft length each. The four emergency runway sections become operational by removing removable concrete medians using forklifts. The Pakistan Air Force (PAF) has used the M2 motorway as a runway on two occasions: for the first time in 2000 when it landed an F-7P fighter, a Super Mushak trainer and a C-130 and, again, in 2010. On the last occasion, the PAF used a runway section on the M2 motorway on 2 April 2010, to land, refuel and take-off two jet fighters, a Mirage III and an F-7P, during its Highmark 2010 exercise. In March 2019, Pakistan also used a section of M2 motorway to land its fighter jets to demonstrate its capability.

Poland
A large number of highway strips (DOL - Drogowy Odcinek Lotniskowy, lit "road airfield section") were built during the Cold War in Poland. As of 2003, only one highway strip is used annually for an exercise.

Singapore
The Republic of Singapore Air Force periodically conducts an "alternate runway exercise". It was first conducted on 17 April 1986 with F-5 and A-4 aircraft. The seventh exercise, "Torrent 2016", was conducted near Tengah Air Base in November 2016. Signs, street lights and other fixtures were removed, and landing equipment installed temporarily, which included mobile arresting gear for the first time. F-15SG and F-16C/D fighters participated in the 2016 exercise.

South Korea
As with North Korea, South Korea has also established a number of highway strips.

Soviet Union
A large number of highway strips were built in the former USSR (Аэродромный Участок Дороги, "airfield part of road").

Sri Lanka
Tamil separatist group Liberation Tigers of Tamil Eelam (LTTE) operated in northern Sri Lanka prior to their elimination in 2009, used highways as landing strips.

Sweden


Sweden started establishing road runways (reservvägbaser) as alternative bases with the introduction of the Bas 60 system in the late 1950s. The Six-Day War in 1967 (where the Egyptian Air Force was grounded by a quick surprise attack on air bases) and the introduction of long range attack aircraft (primarily the Su-24) inspired further development, resulting in the Bas 90 system. Improvements in the Bas 90 system included construction of short backup runways in the direct vicinity of the air bases and further dispersion of ground operations. The Viggen and the Gripen were both designed with STOL capability in order to utilize shorter runways.

The Swedish Air Force did not practice using their road bases for around a decade in the early 21st century, but in 2015 and 2016 its Saab JAS 39 Gripen fighters participated in Finnish Air Force road base drills. In September 2017, the air force conducted exercises on a number of road bases for the first time in over a decade.

In preparation for NATO integration, United States aircraft have done some landings on these road strips in the 2020-ies, even if they are considered too narrow according to NATO standard and too short for most military aircraft.

Switzerland
A number of highway strips called NOLA/NOSTA (Notlandepisten) were set up from 1969 to 2004.
 * Oensingen, A1 motorway (training: 1970 STRADA with Venom ),
 * Münsingen, A6 motorway (training: 1974 STRADA with Venom, Hunter and P-3. 1982 TAUTO with Hunter and Tiger.),
 * Flums, A13 motorway (training: 1977 NOLA with Hunter and anti-aircraft warfare (AA), 1985 TAUTO with Hunter and Tiger),
 * Alpnach, A8 motorway (NOSTA) connected to Alpnach Air Base (training: 1978 NOSTA with Hunter),
 * Lodrino, A2 motorway connected to Lodrino Air Base (training: 1991 STRADA with Hunter, Tiger and AA ),
 * Bex, A9 motorway (training: 1980 ABEX with 36 Hunter ),
 * Sion, A9 motorway connected to Sion Air Base (training: 1988 with Tiger
 * Payerne, A1 motorway connected to Payerne Air Base.

Taiwan
Taiwan built a number of highway strips (戰備跑道, lit. "war spare runway").

United Kingdom
During the Cold War, the Royal Air Force launched Jaguar aircraft from the M55 motorway between Preston and Blackpool have been tested. Areas such as Teesside, Southend and Liverpool have been considered for highway strip areas as large civilian airports such as Glasgow and Heathrow would be unavailable. Another advantage to this is that the more the jet fighters are spread, the harder it is for the enemy to target.

United States
A persistent myth claims that "one mile in every five must be straight for use as an airstrip in times of war or other emergencies". However, no legislation containing this provision was ever passed. The Defense Highway Act of 1941 provided for the operation of "flight strips" alongside highways, but did not mandate the use of the road itself.

For Exercise Northern Strike 2021, A-10 Thunderbolt IIs from the 354th Fighter Squadron and the 127th Wing of the Michigan Air National Guard along with two C-146A Wolfhounds from the Air Force Special Operations Command participated in the exercise. The aircraft landed on state highway M-32 as part of Northern Strike 21, a large-scale training exercise, in Alpena, Michigan. This was the first time that United States military aircraft had used highways as airstrips on American soil. The United States Air Force repeated this training with the Rally in Rockies exercise from the 12 to 17 September.