Instruct: Given a question, retrieve documents that answer the question.
Query: What's the longest highway in the world?
The Pan-American Highway[1] is a network of roads stretching across the American continents and measuring about 30,000 kilometres (19,000mi)[2] in total length. Except for a rainforest break of approximately 160km (100mi), called the Darién Gap, the roads link almost all of the Pacific coastal countries of the Americas in a connected highway system. According to Guinness World Records, the Pan-American Highway is the world's longest "motorable road". However, because of the Darién Gap, it is not possible to cross between South America and Central America with conventional highway vehicles. Without an all-terrain vehicle, it is necessary to circumnavigate this terrestrial stretch by sea.
Despite what its name may suggest, the speed limit on the highway is less than that of an expressway. The highway also has a traffic light junction at its intersection with Clementi Road, something that expressways do not have. The at-grade section of the highway is a three-lane dual carriageway, and the viaduct is a two-lane dual carriageway with a 1-metre hard shoulder. At a length of 5 km, the viaduct is the longest in Singapore.
The railway line has the longest straight section of railway in the world (), while the Eyre Highway (refer below) contains the longest straight section of tarred road in Australia ().
Certain older parts of Plainfield have suffered from extreme traffic congestion. Before Interstate 55 was built just east of the town in the late 1950s, U.S. Route 30, The Lincoln Highway and U.S. Route 66 (sometimes referred to as "The Mother Road") merged into one street for three blocks on what is now Illinois Route 59. This merge is now only shared by U.S. 30 and Lincoln Highway, between Plainfield/Joliet Road on the south to Lockport Street on the north, but continues to be an area of heavy traffic congestion even outside heavy commuting periods. At one time, the two longest paved highways in the world (Lincoln Highway and U.S. Route 66) crossed within Plainfield. The highways only crossed each other twice and both locations are in Will County. The other location is in neighboring Joliet.
Major highways are often named and numbered by the governments that typically develop and maintain them. Australia's Highway 1 is the longest national highway in the world at over and runs almost the entire way around the continent. China has the world's largest network of highways followed closely by the United States of America. Some highways, like the Pan-American Highway or the European routes, span multiple countries. Some major highway routes include ferry services, such as U.S. Route 10, which crosses Lake Michigan.
Yonge Street was formerly a part of Highway 11, which led to claims that Yonge Street was the longest street in the world. Running (mostly) concurrent with Yonge as far north as Barrie, then continuing beyond through central and northern Ontario to the Ontario-Minnesota border at Rainy River, the highway was over long. But Yonge Street could only be called the longest street in the world if were fully synonymous with Highway 11, which has never been the case.
At just over , SR 11 is the longest state highway in Maine, and the second longest numbered highway in the entire state (behind US 1, which runs just over in Maine). It is almost longer than Maine's longest Interstate Highway, its section of Interstate 95 (I-95). Overall, Route 11 in Maine, New Hampshire, and Vermont are long.
Vermont Route 100 (VT 100) is a north–south state highway in Vermont in the United States. Running through the center of the state, it travels nearly the entire length of Vermont and is long. VT 100 is the state's longest state highway, the longest north-south route in Vermont, and the longest numbered highway in Vermont of any type.
The northeastern point of Highway 1 passes through the region in the city of Cairns and connects the southern-running Bruce Highway to the western-running Savannah Way. Highway 1 circumnavigates the continent at a length of approximately and is the second-longest national highway in the world after the Pan-American Highway. Despite being Highway 1, not all sections of the Savannah Way are designated as a federally funded National Highway and certain sections remain unsealed.
By the end of 1937, the Middle Road was open between Toronto and Burlington, and would soon connect with what was first known as the "Hamilton–Niagara Falls Highway". When it opened, it was the first intercity divided highway in North America
and boasted the longest continuous stretch of illumination in the world until World War II.
It soon came time to name the new highway, and an upcoming visit by King George VI and Queen Elizabeth proved to be the focal point for a dedication ceremony. On June 7, 1939, the two royal family members drove along the highway (which now connected to Niagara Falls) and passed through a light beam near the Henley Bridge in St. Catharines. This caused two Union Jacks to swing out, revealing a sign which read "The Queen Elizabeth Way".
Eyre Highway begins at the town of Norseman, on the Coolgardie–Esperance Highway. Apart from Eucla, from the South Australia border, roadhouses serving the highway are the only settlements on the stretch through Western Australia. These are located apart, at Balladonia, Caiguna, Cocklebiddy, Madura, and Mundrabilla. The section between Balladonia and Caiguna includes what is regarded as the longest straight stretch of road in Australia and one of the longest in the world. The road stretches for without turning, and is signposted and commonly known as the "90 Mile Straight". Travelling east, the highway descends through the Madura Pass just before the Madura roadhouse from the Nullarbor Plain to the coastal Roe Plains. It skirts the bottom of the escarpment, climbing back through the Eucla Pass just before Eucla.
Because of its remoteness, some widened sections of the highway serve as emergency airstrips for the Royal Flying Doctor Service. These airstrips are signposted, have runway pavement markings painted on the road, and turnaround bays for small aircraft.
The GTA also consists number of King's Highways and supplemented by municipal expressways. One of the most principal highways in the GTA, Highway 401, is also the longest in Ontario and is also one of the busiest highways in the world. Notably, a segment of the highway passing through the GTA holds the distinction of being North America's busiest highway. The GTA is laced with a number of limited-access highways, including the 400-series highways. These include:
Provincial downloading separated Yonge Street from Highway 11 during the 1990s. As a result, Highway 11 does not start until Crown Hill just outside Barrie, several kilometres north of where the name "Yonge Street" ends. The Guinness Book of World Records no longer lists Yonge Street as the longest street in the world and has not chosen a replacement street, but cites the Pan-American Highway as the world's longest "motorable road".
RN40 is the longest route in Argentina and one of the longest in the world alongside such routes as U.S. Route 66, Canada's Trans-Canada Highway, and Australia's Stuart Highway, more than long. At its traditional southern end near the city of Río Gallegos, it starts at sea level. It then crosses 20 national parks, 18 major rivers, and 27 passes in the Andes. Route 40's highest point is in Abra del Acay in Salta Province.
Highway 18 is a highway in the Canadian province of Saskatchewan. It runs from Highway 13 near Robsart, approximately east of the Alberta border, to the Manitoba border near Gainsborough, where it becomes Highway 3. It passes through three major communities, all in the eastern quarter of Saskatchewan – Estevan, Oxbow, and Carnduff; it also passes north of the west and east blocks of Grasslands National Park. Highway 18 is about long, which is the longest east-west highway and second longest highway in Saskatchewan.
State Highway 16, or SH 16, is a south–north state highway that runs from Zapata on the Texas-Mexico boundary to U.S. Highway 281 24 miles (38.6 km) south of Wichita Falls. It is the longest state highway in Texas at almost 542 miles, but is only the 9th longest of any highway classification in the state. Before the 1939 renumbering, SH 4 was the longest state highway. 
Australias Highway 1 is a network of highways that circumnavigate the country, joining all mainland state capitals. At a total length of approximately it is the longest national highway in the world, surpassing the Trans-Siberian Highway (over ) and the Trans-Canada Highway (). Every day more than a million people travel on a part of it.
Unlike most Interstate Highways, much of I-70 in Utah was not constructed parallel to or on top of an existing U.S. Highway. Portions of I-70 were constructed in areas where previously there were no paved roads. Because it was built over an entirely new route, I-70 has many features that are unique in the Interstate Highway System. For example, the between Green River and Salina makes up the longest distance anywhere in the Interstate Highway System with no motorist services. This same piece is noted as the longest highway in the United States built over a completely new route since the Alaska Highway, and the longest piece of Interstate Highway to open at a given time. The construction of the Utah portion of I-70 is listed as one of the engineering marvels of the Interstate Highway System.
Lake Shore Road was macadamized during the 19th Century, although it was frequently damaged by erosion. With the advent of automobile use in the early 20th Century, it was chosen as the route of the proposed "Toronto-Hamilton Highway" in 1914 as part of the "Provincial Highway" (Highway 2). The Toronto-to-Hamilton highway which, when completed in 1917, was both Ontario's first concrete highway and one of the longest such inter-city stretches in the world. 
In Canada, the first precursor with semi-controlled access was The Middle Road between Hamilton and Toronto, which featured a median divider between opposing traffic flow, as well as the nations first cloverleaf interchange. This highway developed into the Queen Elizabeth Way, which featured a cloverleaf and trumpet interchange when it opened in 1937, and until the Second World War, boasted the longest illuminated stretch of roadway built.
A decade later, the first section of Highway 401 was opened, based on earlier designs. It has since gone on to become the busiest highway in the world.
The following is a list of U.S. Highways in Maryland. There are currently 14 U.S. Highways that exist entirely or partially in the U.S. state of Maryland. Seven of these are primary U.S. Highways while seven are auxiliary U.S. Highways that may or may not be related to one of the primary U.S. Highways. The longest primary U.S. Highway in Maryland is U.S. Route 40 (commonly abbreviated US 40) at . The shortest primary U.S. Highway in Maryland is US 11 at . The longest auxiliary U.S. Highway in Maryland is US 301 at . The shortest auxiliary U.S. Highway in Maryland is US 522 at . All U.S. Highways are maintained by the Maryland State Highway Administration except for the portions that run through Baltimore, Hagerstown, and Cumberland. Maryland has five former U.S. Highways; those five are shaded in dark gray in the list.
The Trans-Siberian Highway is the unofficial name for a network of federal highways that span the width of Russia from the Baltic Sea of the Atlantic Ocean to the Sea of Japan. In the Asian Highway Network, the route is known as AH6. It stretches over from St. Petersburg to Vladivostok. The road disputes the title of the longest national highway in the world with Australia's Highway 1.
The highway became fully paved on 12 August 2015.
This highway links the cities of Luntai () on National Highway 314 and Minfeng () on National Highway 315, on the northern and southern edges of the Tarim Basin. The total length of the highway is 552 km; approximately 446 km of the highway cross uninhabited areas covered by shifting sand dunes, making it the longest such highway in the world.
At , it is the largest highway project in India and the fifth longest in the world. It is the first phase of the National Highways Development Project (NHDP), and consists of four- and six-lane express highways, built at a cost of . The project was planned by 1999, launched in 2001, and was completed in 2012.
In 2012, a series of free public electric vehicle charging stations were installed along the main route of the highway by a private company, Sun Country Highway, permitting electric vehicle travel across the entire length, as demonstrated by the company's president, Kent Rathwell, in a publicity trip in a Tesla Roadster. As of 2012, this made it the longest electric-vehicle-ready highway in the world.[19][20]