The widest highways in the world

Which is the longest road ever built? And the most dangerous? And which are the widest highways in the world? Questions such as these are by no means rare. They may come up on a car journey, for example, as you are driving along a particularly wide or long highway. Or they may arise simply out of an interest in engineering or city planning, since we know that there are many very different types of roads in the world of road networks and traffic. We know, for example, that the longest highway in the world is the famous Pan American Highway, that extends for an amazing 25,750 kilometres across North and South America, and that the busiest road for traffic is the National Expressway 110 in Beijing, China. But which is the widest highway in the world? It is no simple matter to answer this question, since different administrations have tried to claim that record at various times. But it is important to note that winning this record also depends on the type of requirements selected for consideration: should side roads be considered? Should we count the number of lanes or the actual width of the carriageway in metres? Let’s take a look in any case at the roads and highways that currently stand out because of their width.

The largest road in the world: Avenida 9 de Julio, in Buenos Aires

Before considering which are the biggest highways in the world, it is worth taking a look at the widest city street in the world. The most famous Avenues in the world include roads such as Broadway and the Avenue des Champs-Elysées, but the title of the widest avenue in the world should probably go to Avenida 9 de Julio, one of the major arterial roads cutting through the centre of Buenos Aires, in Argentina. The road is named after the date of national independence, that is, 9 July 1916. This 4-kilometre-long city street is a good 140 metres wide: by comparison, a standard football field is 105 metres long.

The Avenida 9 de Julio was planned in 1888, and involved clearing a long sequence of apartment blocks, connecting the Retiro district and arriving at Constitucion station; however, the works were continually postponed due to forceful protests by the residents as well as legal claims. The works only started in 1936 and proceeded very slowly. The first part of the road was completed in 1960, and the Avenida was finally finished about 20 years later.

The widest highways in the world: the two record-beating roads

After this brief digression on city streets, let’s turn now to the most famous highways in the world in terms of width.

Katy Freeway, Houston

It may at first sight seem obvious that the title of the widest highway in the world should be awarded to the Katy Freeway in Houston, Texas. More specifically, this is a section of the Interstate 10 in the state of Texas, the road which crosses the country from Anthony, on the border with New Mexico, to Orange, on the border with Louisiana, thus passing through cities such as El Paso, San Antonio and of course Houston. And it is in Houston, the city famous throughout the world for its Space Centre, that the highway became known as the busiest in the United States in the early 2000s, with the worst “bottleneck” in the country. That was why it was decided to widen part of the Katy Freeway, with the works completed in 2008.

The widening of this section of the highway cost 2.8 billion dollars: according to the claims of the local authorities and many US daily newspapers, the Interstate 10 now has 26 lanes at this point. From this point of view, the Katy Freeway would without any doubt overtake the highways that had until then been considered the widest highways in the USA, that is, the I-75 at Atlanta, with 15 lanes, and the I-405 at Los Angeles, with 14 lanes. It was the then mayor of Houston, Sylvester Turner, in particular who claimed the record for the widest highway in the world. But some observers pointed out that the total of 26 lanes also includes side roads, which don’t actually make up part of the Interstate 10 highway, and hence not the Katy Freeway either: the actual number of lanes needs to be recalculated, therefore, arriving at a total of 18 lanes. It is still sufficient to make the Katy Freeway the widest highway in the United States, but not for it to be recorded as the absolute widest in the world.

King’s Highway 401 in Ontario

Remaining in North America, there is definitely at least one highway that has as many lanes as the Katy Freeway at Houston: this is the King’s Highway 401, in Ontario, Canada, which reaches 18 lanes when it gets to Toronto, more specifically, in the vicinity of Pearson International Airport; moreover it is a highway that sees about half a million “transits” a day.

Expressway G4 Beijing-Hong Kong-Macao

If we explore further, we discover that the record for the broadest highway in the world has also been claimed by the Expressway G4 Beijing-Hong Kong-Macao: it is possible to find photographs of this arterial road with as many as 50 automobile lanes, one next to another. This would automatically make it the widest highway in the world. But we must point out that this photo does not show the actual highway, but rather the lanes at a highway tollbooth, so it does not actually reflect the true number of lanes of the highway itself; in fact, after the tollbooth the number of lanes falls from 50 to 20, and eventually to the traditional four after a few kilometres.

But is it really useful to build highways with such a high number of lanes? Obviously, the objective here is to provide more space for the flow of cars, to reduce the potential for traffic jams and bottlenecks. But we should note that various studies show that this is not actually what happens: increasing the capacity of a highway beyond a certain number of lanes, does not help to reduce traffic in the long term, in fact, due to a phenomenon known in economics as “induced demand”. As the available “free” space increases, demand also increases and with it the traffic.