Talk:Induced demand

induced != latent

though they are similar, the two terms are not interchangeable. one way to think of the difference: Latent demand is a part of the phenomenon of induced demand. induced demand is an increase due to more capacity. latent demand is potential demand but is constrained because of congestion, kind of like potential energy stored until it's released. Source: ‘Suburban Nation’ by Andres Duany et al [1] :: “This condition is best explained by what specialists call latent demand. Since the real constraint on driving is traffic, not cost, people are always ready to make more trips when the traffic goes away. The number of latent trips is huge--perhaps 30 percent of existing traffic. Because of latent demand, adding lanes is futile, since drivers are already poised to use them up.” El duderino ^(abides) 06:57, 26 January 2015 (UTC)

That's because reliable sources say otherwise. Beyond My Ken (talk) 05:06, 28 January 2019 (UTC)

Nope, WP:RS beats WP:OR every day of the week and twice on Sundays. Beyond My Ken (talk) 05:17, 28 January 2019 (UTC)

"Induced demand", "latent demand", and "effective demand" are economic terms. Examples: An enlarged/upgraded street may "induce" more traffic to use that street over others (not necessarily increasing traffic in the area overall), or war mongering may induce demand for military hardware; "latent demand" is demand not yet visible (unknown) to the market, as opposed to "effective demand" or "market demand" or simply, "demand". "Induced demand" is new demand caused by some change in condition; "latent demand" already exists but is not visible (not yet effective demand) because of some current constraint: price, distribution, marketing, raw material, etc. Cmoneti (talk) 16:53, 28 January 2019 (UTC)

"Induced demand" is new demand caused by some change in condition; "latent demand" already exists but is not visible (not yet effective demand) because of some current constraint: price, distribution, marketing, raw material, etc. And if the constraint changes that's a change in condition. For instance, if the constraint is the number of lanes available to travel from A to B then an enlarged/upgraded street will create more demand. Whether that demand is "induced" or "latent" cannot be determined without close study of the specifics of the demand. Until that is done, "induced demand" and "latent demand" are essentially the same thing. Beyond My Ken (talk) 17:30, 28 January 2019 (UTC)

The inability (in some cases) to determine whether "induced" demand derives from a transformation of "latent demand" to "effective demand" rather than the creation of a new demand does not make "induced demand" the same as "latent demand". "Induced demand" is part of actual, i.e., "effective demand"; those two may be thought of as the same in some general contexts. But, "latent" demand" is the conceptual opposite of "effective demand", so "latent demand" and "induced demand" cannot be the same. Cmoneti (talk) 05:27, 29 January 2019 (UTC)

Got a reliable source that says any of this? Beyond My Ken (talk) 08:30, 29 January 2019 (UTC)

The prefix terms of Induced, effective, latent, market, derived, etc., all denote a type of demand. Their purpose is to help distinguish the origin, evolution, or current state of the "demand" being discussed. "Induced Demand" -- https://nacto.org/references/lee-douglass-b/ "“Induced” is a term implying that a particular condition is indirectly caused by another condition. In the case of traffic volumes, the term arose from the phenomenon that improvements to a highway -- especially capacity improvements -- seemed to result in more traffic choosing to use the road than would be the case if the highway were not improved." "Latent Demand" -- https://dictionary.cambridge.org/dictionary/english/latent-demand "Derived Demand" -- https://dictionary.cambridge.org/dictionary/english/derived-demand "Market Demand" -- https://dictionary.cambridge.org/dictionary/english/market-demand?q=%22market+demand%22 "Induced Demand" -- (N/A. But see "Induced Investment", same concept) https://dictionary.cambridge.org/dictionary/english/induced-investment "Derived Demand" is the more traditional economics term for the recently popular "induced demand"; they are the same. Cmoneti (talk) 17:25, 29 January 2019 (UTC)

Sorry, dictionary defintiions aren;t going to do it. That's WP:SYNTH. Because the subject-specific source we have at the moment says otherwise, we're going to need a citation from a reliable source that says what you're saying. Beyond My Ken (talk) 20:18, 29 January 2019 (UTC)

Forgive me, I'm new to editing and I don't understand. Since we are talking about established terms and definitions (as opposed to, e.g., opinion or description of events), why is the dictionary not an acceptable source? And what's wrong with the nacto.org source (National Association of City Transportation Officials)? Cmoneti (talk) 22:56, 29 January 2019 (UTC)

Got any reliable sources that say that "induced demand" is the same as "latent demand"? Maybe that will help me understand. Cmoneti (talk) 22:56, 29 January 2019 (UTC)

I finally read the whole article. Nowhere did I see a section offering a clear definition of "induced demand" as the page title suggests. There is only the very clumsy first sentence with no sources. The rest of the article is specifically about the phenomenon of induced traffic in the discipline of traffic engineering. Seems to me that lengthy discussion deserves its own page. Cmoneti (talk) 22:56, 29 January 2019 (UTC)

I think the page should be short, including a concise definition of "induced demand", noting that it is a term primarily from traffic engineering that is analogous to "derived demand" from economics; there could additionally be 1-3 paragraphs to expand/characterize the phenomenon in traffic engineering that the term refers to, including a reference to Braess's Paradox and other terms perhaps already existing on wikipedia. Cmoneti (talk) 16:53, 30 January 2019 (UTC)

I did not find a clear definition of "induced demand" in the Cervero article on page 3 or anywhere else. There is a clear definition in the first sentence of my previously suggested source: https://nacto.org/references/lee-douglass-b/ "“Induced” is a term implying that a particular condition is indirectly caused by another condition." Cmoneti (talk) 16:53, 30 January 2019 (UTC)

The Douglass Lee definition is valuable. The Cervero definition is on page 4 line 8 where he writes that "Most have embraced definitions of induced travel similar to that of Schmidt and Campbell (1956):'The added component of traffic volume which did not previously exist in any form, but which results when new or imporved transportation facitilities are provided'."--Tedweverka (talk) 05:22, 31 January 2019 (UTC)

An inaccurate definition, in my opinion. Induced demand is as likely (or more so) to be traffic drawn from other streets as it to be completely new demand. Cmoneti (talk) 16:46, 31 January 2019 (UTC)

This is precisely his point. The intent of excluding from the definition of "induced traffic", the traffic that changes modes in response to increased capacity on a particular freeway is to separate the measure of "induced demand" from the number of trips that merely change mode. It is part of the definition that Cuervo claims "Most have embraced".--Tedweverka (talk) 06:52, 1 February 2019 (UTC)

"Induced demand" and "latent demand" are distinct terms: in name, in use, and etymologically. An online survey of the terms' use quickly and thoroughly confirms this. I have found no source that suggests otherwise. No source is needed to assert that "induced demand" is different from "latent demand" any more than to assert that an infant is understood to be smaller than an adult. One can talk about "induced demand" without mentioning "latent demand"; the onus is on the person who asserts that "induced demand" is the same a "latent demand" to show those terms are the same or analogous. Cmoneti (talk) 16:53, 30 January 2019 (UTC)

Again, what is the reliable source that backs this up? Beyond My Ken (talk) 00:25, 31 January 2019 (UTC)

With all due respect, that reads like a non sequitor to what I wrote. Cmoneti (talk) 16:46, 31 January 2019 (UTC)

That's because all you keep doing is repeating your opinion, which is OR and SYNTH and therefore, frankly, useless. You need a reliable source, and you cannot provide one. Why not? Beyond My Ken (talk) 17:06, 31 January 2019 (UTC)

• Let me make this perfectly clear: no matter how many people come here and express their unsupported personal WP:OR opinion, "latent demand" will not be removed from the article, because it is supported by a reliable source, and the opinions of the so-called "consensus" are not -- they are not only not supported, but rely on a WP:SYNTH argument: that because the words "induced" and "latent" have different dictionary defintiions, therefore "induced demand" and "latent demand" must be different concepts. For this reason, the "consensus" here is not a legitimate consensus, but is an example of a WP:Wrongful consensus.
  If anyone has a reliable source which supports the removal of "latent demand", then the consensus would be legitimate and can be put into effect, but we simply do not recognize personal opinions as legitimate material for articles, in fact, it is expressly forbidden by WP:Original research. All of the opinions above are WP:OR, therefore none of them can be used to justify the removal of information supported by a reliable source.
  I'm putting everyone here on notice that continuing to edit war over this will not end well. Your choice is baldly simple: get a reliable source. Beyond My Ken (talk) 00:32, 31 January 2019 (UTC)

• Cmoneti -- with their handful of edits to Wikipedia, almost all of them to this talk page -- is incorrect, and does not understand Wikipedia policy. The equivalence is sourced, and that's all that's needed. Get yourself a reliable source, and this discussion is over in your favor. As it is now, the article stays in the WP:STATUSQUO. Beyond My Ken (talk) 05:54, 31 January 2019 (UTC)

Where is the source for the equivalence? I don't see it on the page. Cmoneti (talk) 16:46, 31 January 2019 (UTC)

• Beyond My Ken -- refuses all offered sources, and insists the induced/latent equivalence is sourced, yet does not provide it. Well, I believe I have found the initial source for this article: https://www.youtube.com/watch?v=DqqjT3Xq620 . If one listens to the audio while viewing this article, one can clearly identify the same structure and much of the same sentences or whole paragraphs, including the exact same contested statement at the beginning of this article. 'The source is nothing more than a Youtube click bait video, hardly a reliable source.' Cmoneti (talk) 00:12, 1 February 2019 (UTC)
• Beyond My Ken -- removing the offending clause, "or latent demand," removes an assertion (and without impact on rest of the article). A source may be required to add an assertion, not to remove it. Cmoneti (talk) 00:12, 1 February 2019 (UTC)

• Sorry, that is not the case, you really don;t know what you're talking about -- but why shouldl you? You made one edit 14 years ago, and then didn't edit again until you started here. The bottom line is: you need a reliable source to support your opinion, and you still haven't got one. Get one, and this argument is settled, in your favor. That you haven't provided one strongly indicates that either (1) you're not trying, or (3) there is not one to get. Beyond My Ken (talk) 00:16, 1 February 2019 (UTC)

• I had an impeccable source 14 years ago on economist J.B. Say's so called "Say's Law": his own words in his own language from his original 1832 treatise publication. Don't know why it was removed, but economics is political. Cmoneti (talk) 04:40, 1 February 2019 (UTC)
• I'm still waiting for you to declare your source. What's the hangup? Cmoneti (talk) 04:40, 1 February 2019 (UTC)

• You're drowning in sources, friend, every single one of which says that while there is a technical distinction to be made between "induced demand" and "latent demand", the two terms are used interchangeably.
  You want more, 'cause I can keep plucking them, they're out there to be picked. Where's your source that says they're not used interchageably? Beyond My Ken (talk) 01:02, 1 February 2019 (UTC)

• Yes! I want more! You say you can "pluck" them, but you haven't shown any. Where's the one you've been claiming all this time? Cmoneti (talk) 04:35, 1 February 2019 (UTC)

Could it be that "latent demand" and "induced demand" are the same thing, but the phrase used depends on one's POV with respect to the desirability of the commodity in question? Latent demand is the unsatisfied demand for a commodity that one approves of, released when supply of that desirable commodity is increased - whilst induced demand is the unsatisfied demand for a commodity that one disapproves of, released when supply of that undesirable commodity is increased. Just a thought. -- DeFacto (talk). 07:18, 1 February 2019 (UTC)

They are basically the same thing, which is why the terms are used interchangeably. Latent demand cannot be satisfied because of constraints in the system -- such as the lack of roads, or roads that are in bad condition, or do not have enough capacity -- and when those constraints are released -- by new or improved roads, for instance -- the new traffic that was called "latent" when it was pent-up is called "induced demand". I don't believe that approval or disapproval has anything to do with it, it's entirely about the throughput of the system, before and after. The latent demand is latent because it needs constraints to be removed, and when they are removed it become induced demand. Two sides of the same coin, but latent demand is mostly theoretical (the problem being how to accurately determine it empirically -- perhaps by surveys and polling?) while induced demand can be seen, counted, analyzed, etc.

The point is, they are two names for the same thing, mirror images on either side of the removal of constraints. Beyond My Ken (talk) 07:34, 1 February 2019 (UTC)

@Beyond My Ken: yes, I'm suggesting that they are the same thing, but named differently depending on personal bias. You seem to be defining them as two subtly different things - one as the unsatisfied demand resulting from lack of supply and the other as increased consumption following supply increase. Under your definition the two may not be equal, especially if the increased supply is insufficient to fulfil all of the unsatisfied demand. -- DeFacto (talk). 10:52, 1 February 2019 (UTC)

Yes, I would agree with that description. They are the same thing if the additional capacity of the channel (or the additional supply) is sufficient to satisfy all the Latent Demand. Beyond My Ken (talk) 10:56, 1 February 2019 (UTC)

Put it this way:

• If Latent Demand = additional capacity of the channel (AC), then Induced Demand = Latent Demand
• If Latent Demand < AC, then Induced Demand = Latent Demand + any new Generated Demand
• If Latent Demand > AC, then Induced Demand = Latent Demand, and New Latent Demand = (Old Latent Demand - AC) [i.e. there is unsatisfied Latent Demand]

But, again, these would be technical definitions, and -- as the citations provided show -- "Induced Demand" and "Latent Demand" are very often used interchangeably, probably because of the extreme difficulty in determining what the Latent Demand is in any particular case before removing the constraints on the system, while the Induced Demand can be empirically counted once the channel has been modified. That makes Latent Demand a much less useful, and much more theoretical, concept. Of course, if you're going to build a new road, it's probably a good idea to have some sense of what the existing Latent Demand is, given the cost of building roads, but I suspect that, given the difficulty of determining that, they probably estimate the Latent Demand by the seats of their pants and various "tricks of the trade".

It's interesting to note that much of the criticism of the concept of Induced Demand is ideologically-based, not scientifically- or empirically-based. Beyond My Ken (talk) 11:17, 1 February 2019 (UTC)

My point about term selection based on bias is that those who object to the increase in supply of a particular commodity will argue that it is the provision of extra supply which creates (or induces) the demand, hence they use the term "induced demand", whereas those who support the increase in supply will argue that the extra demand already exists (it is latent), hence they use the term "latent demand".

For example, political support or opposition for the provision of extra supply of a particular commodity can hinge on whether the demand is considered to be latent or induced! For instance, governments may choose to support calls for improved infrastructure to reduce broadband network congestion as it will satisfy the latent demand, where they would oppose calls for improved infrastructure to reduce road network congestion as it will create induced demand and soon become congested itself. -- DeFacto (talk). 11:53, 1 February 2019 (UTC)

Great discussion. You have demonstrated in your own word usage a repeated distinction between "latent" and "induced" demand, namely that "induced demand" is transformed from "latent demand"---or the presumption of this conceptual quantity. There are several defined types of "demand"; they are all demand but not equal; they exist to distinguish and clarify the causal and temporal context of the subject at hand. In other words, infants and adults are both human beings, but they are not the same; one evolves into the other, just as "latent demand" may be transformed into "effective demand", of which "induced demand" is a part. Cmoneti (talk) 15:41, 1 February 2019 (UTC)

induced demand != demand

The current page defines induced demand by its consquence, but it refers to a phenomenon due to plain old "demand". Plain old demand is the phenomenon that after supply increases, more of a good is consumed.--73.229.196.41 (talk) 18:43, 6 February 2019 (UTC)

The first paragraph is a rambling list of associations. It needs a rewrite.--73.229.196.41 (talk) 18:45, 6 February 2019 (UTC)

ENGVAR

I've made a couple of consecutive edits today per MOS:ENGVAR (particularly MOS:ARTCON) from "travelled" to "traveled" and "travelling" to "traveling", as it appears to me that most of the article is written in US English. At the same time I changed "vehicle-kilometres" to "vehicle-miles" as the rest of the article states distances in miles... there is only one use outside a quote (200 miles) and I am not sure whether this would benefit from a {{convert}}), and I'm also not sure if "vehicle-mile" needs the hyphenation (it is not hyphenated in a quote). 94.21.10.214 (talk) 09:51, 20 December 2019 (UTC)

I've linked Vehicle miles of travel, a targeted redirect to Units of transportation measurement#Traffic flow, and removed the hyphens in "vehicle miles" as it is defined there unhyphenated. 94.21.10.214 (talk) 10:05, 20 December 2019 (UTC)

Actually I'm wrong... the definition is for "vehicle-mile" with a hyphen, but the redirect itself has "vehicle miles" without one. I'll leave it without, for now, following the usage in the quote. 94.21.10.214 (talk) 10:07, 20 December 2019 (UTC)

I did some google ntrans on this and "vehicle miles" beats "kilometres" about five to one, but I am not sure that tells us much. I put in variant spellings of "kilometers" and singular "mile" but I regard the results with suspicion as I cannot believe "vehicle-mile" or "vehicle mile" was never used in a book. Certainly all four terms shot up in use after about 1970. We should probably stick to miles as that is in the quotes and so on, except one British reference uses vehicle kilometres which is actually a bit odd since in the UK distances on roads must by statute be measured in miles (one of the few things that MUST be in Imperial, the other being a pint of beer (or half or third or multiples thereof), cider or perry on draught. Milk and orange juice may be sold in pints if delivered in returnable containers. I worked for many years as a barman and milkman in the UK.... 22:32, 20 December 2019 (UTC) — Preceding unsigned comment added by 94.21.10.214 (talk)

"Draught beer and cider may only be sold in a third of a pint, two-thirds of a pint, half a pint or multiples thereof".[2] NIST in the US allows milk to be sold in various US Customary sizes, ranging from a third of a pint to two gallons. There seems to be a distinction that I believe in UK law it is simply "returnable containers" whereas NIST seems occasionally to state "glass containers (bottles)" and contrariwise says "bottles or plastic". As far as I can see, neither requires the container actually to be returned, only that it be returnable. 94.21.10.214 (talk) 22:54, 20 December 2019 (UTC)

Demand

"In the short term, increased travel on new road space can come from one of two sources: diverted travel and induced traffic."

No. Over-density & over-development lead to a repression of possible travel. When roads appear, they are used. This is why we are headed towards a major disaster as we have people who think they know, when they don't.

Nantucketnoon (talk) 08:56, 19 January 2021 (UTC)