Demographic growth, urban development and the great automobile boom crossed paths in the 20th century to give rise to some of the most spectacular roads today: from the Panamericana that has never closed to the road with the longest straight line in the world. Logic leads us to think: if there are more cars, then more lanes are needed to avoid traffic jams (spoiler: from one point on, not working). And if we talk about roads with more lanes, there is one place that takes the cake: the Interstate 10 in the United States.
The point that interests us in question is in Houston, Texas: there an ordinary six-lane highway from the 60s became thanks to an astronomical widening of the widest road on the planet. It is this American highway that holds the record with 26 lanes and not a chinese highwaydespite the fame of the 50 lanes of the G4 Beijing-Hong Kong-Macao.
The highway with the most lanes is in Texas. Within that highway that crosses the United States from Santa Monica in California to Jacksonville in Florida with a route of 2,460 kilometers in total length there is a specific section known colloquially as the Katy Freeway: a segment about 37 kilometers west of Houston. At its widest point, at Gessner Road, the road has 26 lanes in total: 12 main lanes (six in each direction), 8 service lanes (four in each direction) and 6 central dynamic toll lanes.
This corridor is the backbone of mobility for the entire west of Houston, one of the largest cities in the United States and extremely dependent on the automobile (even for the United States): it has hardly any public transportation, little urban planning and decades of peripheral expansion. In this scenario, the I-10 is more than a highway: it is the artery of mobility and business parks, logistics centers, hospitals and universities that depend on private vehicles are concentrated around it.
An unofficial record, not official. The Katy Freeway holds this record in practice, but it is not official (there is no Guinness for this) because no one has agreed on how to count the lanes. Do you only count those on the main road? There are 14. Do you add the side service lanes and the center toll lanes? You reach 26. Without a single, agreed upon criterion, Guinness cannot set a number and certify it.
Brief history of its construction and expansion. The Katy Freeway was built in the 1960s and had six to eight lanes, sufficient for the mobility needs of the time. But between the 80s and 90s, Houston suffered spectacular urban growth: in 2000, traffic surpassed the 200,000 vehicles when had been designed for 120,000. In 2004, the American Highway Users Alliance (AHUA) classified it as the second most serious bottleneck in the country: they estimated that drivers lost 25 million hours a year.
So the Administration planned a huge road expansion: an investment of 2.8 billion dollars and a four-year project between 2004 and 2008 to incorporate dynamic toll lanes inside an interstate highway for the first time. To make room they demolished an old railway corridor. As a curiosity, in 2014 there was another small expansion to add an auxiliary lane in each direction.
Travel time from Pin Oak to downtown. Source: City Observatory / data: Houston Transtar
More lanes and more traffic jams. Since a picture says a thousand words, above these lines is a graph from the non-profit organization City Observatory with data from Houston’s official traffic agency. City Observatory collects Although the AHUA described in a report that this expansion was one of the great success stories of traffic engineering to alleviate traffic jams and traffic jams, this was not the case: the congestion got worse. Just two years later, they recorded that travel times on that 47-kilometer route from the outskirts to downtown Houston increased by 13 minutes in the morning rush hour and 19 minutes in the afternoon.
This phenomenon has a name: induced demand. Thoroughly developed by Gilles Duranton and Matthew Turner in “The Fundamental Law of Road Congestion: Evidence from US Cities“, offers a clear conclusion: vehicle kilometers traveled increase proportionally to the available lanes and the new roads attract more drivers and more trips until the added capacity is saturated.
The G4 toll, seen in Street View
What happens with the G4 Beijing-Hong Kong-Macao. It is common to find references to the G4 as “the 50-lane highway” thus overtaking the Katy Freeway on the right. The reality is another story: as verified by Africa Check with Google Mapsthe G4 is in practice a four-lane highway along almost its entire length of more than 2,000 kilometers.
The expansion to dozens of lanes that usually appears corresponds exclusively to the Zhuozhou toll area (can be verified with Street View), near Beijing, where the number of lanes is expanded punctually to distribute the flow to the toll booths. Just half a kilometer later, it is reduced to four again. In 2015 there was a terrible traffic jam during the week of China’s National Day at that point that caused kilometer-long queues and the spread of that supposed “50-lane highway” when in reality it is the toll infrastructure of an ordinary four-lane road.
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