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Comment by secondraft | Hacker News Reader

> This is misleading - the city controls supply, not demand.

Well. Relevant quote from https://en.wikipedia.org/wiki/Induced_demand

"Trying to cure traffic congestion by adding more capacity is like trying to cure obesity by loosening your belt."

Shitty quote. Induced demand is a lazy intellectual concept that fails to realize that congestion follows a standard supply and demand curve and the price is just being hidden because the monetary cost is usually free for everyone so it’s all based on time cost.

So you add supply, you capture more of the demand that has been there at a lower cost. You didn’t induce shit. You will eventually add enough supply that everyone will be satisfied (see every road not suffering from congestion issues).

”Trying to cure a toilet paper shortage by producing more toilet paper is like trying to cure obesity by loosening your belt.”

Because we don’t charge for roads, users “pay” in congestion delays, so as we widen roads more drivers can use the road at the same “price” measured in minutes of delay. In some cases You might say that increased capacity induced hesitant drivers to drive.

That is the point. There are people who want to go somewhere but congestion is making them not go. Eventually you get a head of it and things are free flowing while everyone gets where they want to go. In middle of nowhere rural area everything is this way. In big dense cities you would need 30+ levels of bridges (at much great expense per user than rural gravel roads).

I will fully agree that cities should build something other than bridges and parking garages. However induced demand is not a factor because cities that are not ahead of so called induced demand are leaving behind (part of) the great advantage of a cities over rural areas: the vast amount of different places you can get to in a short time.

One way of looking at it is to consider the area of road required per citizen during transportation. If a car consumes 10 square meters of road and a bike only consumes 2 square meters of road, converting a car lane into two bike lanes should immediately reduce traffic congestion. If and only if, of course, enough people are able and willing to do so.

Cars can go a lot faster than a bicycle (assuming safety is a concern, there is a reason I don't have a motorcycle - which isn't to say cars are safe) thus per unit time you can get more distance in a car. Which is back to my point: you are throwing away the point of the city with that argument. I realize parking takes more space, but it will be ages before the city rebuilds to the new reality and until then it isn't functioning like it should.

Yes, decreasing the cost to capture more of the demand curve doesn’t need a special term. That’s why “induced demand” is so dumb. The demand was always there, the busy road was just too high a cost.

It still doesn't work, because the places where the roads ultimately end up, cities, cannot add more roads. It has to stop somewhere.

But they can add more roads via tunnels, bridges, etc. People just don’t want to pay the cost but instead of just saying that they handwave with stupid crap like “induced demand” to pretend it’s an intractable problem.

Also, tons of people give no fucks about going to the city. It’s not some grand final destination. Some of the worst congestion points in the Bay Area aren’t anywhere near dense city.

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