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The whole concept of induced demand is really a misunderstanding of the problem. Congestion indicates transportation capacity is below demand. But once the med
by toast0 2y ago
The whole concept of induced demand is really a misunderstanding of the problem.
Congestion indicates transportation capacity is below demand. But once the medium is congested, you can't measure what the demand is; only how long it's congested.
You can reduce congestion by increasing capacity, or decreasing demand. If you have a pandemic and encourage people to stay at home, you'll find that the transportation networks that are still operating have plenty of capacity. If you add another lane to the 405 in LA, you'll find the duration of congestion has a step change reduction, but as population continues to grow, congestion duration will also continue to grow. If you add mass transit capacity, highway congestion duration will likely be reduced too.
When it's a real situation, the question is usually what intervention allows for the most additional transportation capacity given realistic funds availability. Somewhere like the LA area usually takes an all options approach: there is investment in mass transit as well as highways that service mass transit, individual transportation and commercial shipping. Although intentionally reducing population could work too :p
- lazide 2y agoEh, I think that’s a misstatement of market dynamics. Yes, congestion is stating that demand is exceeding capacity. However… Congestion is a pushback signal that reduces actual demand, by reducing quality/utility of the actual ‘product’. Congestion is demand being throttled through the mechanism of reduction in quality/availability, instead of some other mechanism, like increases in pricing (tolls), or reduction in customers (aka population decreases or exclusionary rules) through the natural usage of the system. Due to induced demand. Because there is almost always more ‘low quality’ demand, than ‘high quality’ demand. It’s a type of tragedy of the commons. In any ‘free’ system, it almost always ends up this way (see crazy long wait times in nationalized health systems!) precisely because the other options are excluded. Just like on free ways.
- matsemann 2y ago> Congestion indicates transportation capacity is below demand. But once the medium is congested, you can't measure what the demand is; only how long it's congested. But congestion is also part of what controls the demand. It's not a "true" demand that you're just not seeing because of congestion. Once the congestion is solved, the demand will increase as that changes the attractiveness of driving. Since driving then for some people will outcompete bus, cycling, trains etc., they will then shift over to driving even though they had no demand for it earlier. It will then reach a new equilibrium, not far off the old congestion.