Talks to Watch

Why Traffic Congestion Grows Exponentially, Why It Matters, and What To Do About It // An Explainer

100K views · Dec 16, 2021 · 12:05 · 0 HN recommenders · 4 mentions · discussed 2022–2024

CityNerd explains why traffic congestion grows nonlinearly as more cars use a road network, and why adding road capacity tends not to fix it. It covers the consequences for drivers, bus riders, cyclists and pedestrians, and discusses alternatives such as true bus rapid transit.

Why Hacker News points people here: HN commenters cite it when arguing that congestion is an exponential, feedback-driven problem so widening roads or removing a few cars behaves counterintuitively.

“traffic congestion is an exponential problem”HN comment, 2022

What Hacker News said 4

Cites itjewayneJun 2022

“Here's a video on the topic”

Explains why traffic congestion grows exponentially

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Here's a video on the topic: ("Why Traffic Congestion Grows Exponentially, Why It Matters, and What To Do About It") this video

Cites itnoahtallenJun 2022

“traffic congestion is an exponential problem”

Congestion is exponential so more road capacity does not help

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This is a straw man argument, where you’re using a worst-case scenario for buses. A quick rail line could get you to the office in under an hour, and would beat traffic if it was designed well. Hell, buses ought to skip traffic via dedicated lanes since they’re carrying so many more people than a car. But it’s important to note that only takes 2-3 hours because public transit doesn’t get the investment it needs to be good . And even when cars do get an extreme amount of investment, it still takes you an hour to go 25 miles. It should be clear at this point that driving is not a scalable, general solution for quick, effective transit in areas with lots of people. The pretty simple reason is that traffic congestion is an exponential problem ( this video ). As a result, investing in car infrastructure is actually not a good way to improve your commute time. It may seem backwards, but since more car infrastructure encourages more drivers, and since more drivers increase congestion at an exponential rate , more car infrastructure tends to (at the best case) not improve the situation at all. This is why people like myself really try to push for investment in other forms of transit. If you have multiple, high-quality transit options, some people will pick the train, some will pick a bike, and others will pick a car. If biking and taking the train or bus is good enough that it gets a few drivers off the road, that makes the experience significantly better for you, as we are now decreasi

Cites itxracyNov 2023

Traffic as a positive feedback loop of small disruptions

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ah yes, "traffic enforcement fixes traffic" That's why there exists no traffic in all of the places with traffic police. It's not at all like it's a positive feedback loop where one person messing up parking causes downstream effects for the rest of the day... this video

in “'It gets scary': Neighbors say these Bay Area ghost kitchens are out of control” · view on HN
Cites itxracyJun 2024

“Traffic congestion increases nonlinearly[1].”

Congestion is nonlinear, so removing cars matters more

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Traffic congestion increases nonlinearly[1]. i.e. the 10th car on a road has a smaller effect than the 100th car on the road. Accordingly, the cost of increasing a bus' size and decreasing its speed pales in comparison to the value derived by removing 5-20 cars from the road. this video