Induced demand
In economics, induced demand – related to latent demand and generated demand – is the phenomenon whereby an increase in supply results in a decline in price and an increase in consumption. In other words, as a good or service becomes more readily available and mass produced, its price goes down and consumers are more likely to buy it, meaning that the quantity demanded subsequently increases. This is consistent with the economic model of supply and demand.
In transportation planning, induced demand, also called "induced traffic" or consumption of road capacity, has become important in the debate over the expansion of transportation systems, and is often used as an argument against increasing roadway traffic capacity as a cure for congestion. Induced traffic may be a contributing factor to urban sprawl and affordable housing. City planner Jeff Speck has called induced demand "the great intellectual black hole in city planning, the one professional certainty that every thoughtful person seems to acknowledge, yet almost no one is willing to act upon."
The inverse effect, known as reduced demand, is also observed.