About a month ago a new, multi-lane, multi-million dollar toll bridge opened by my house. I haven’t noticed any difference in traffic.
This wouldn’t be a surprise to many people in the transportation sector. The more roads you build, the more traffic you cause. This is called “induced traffic”. Or, to be more general, “induced demand”.
The idea that building more roads, causes more traffic sounds counter-intuitive at first. Let’s say the government builds 100 brand new roads in your city. Suddenly, there’s a lot more space for driving. People will say, “Hey, driving is awesome. There’s so much room! I’m gonna drive.”
Likewise, if you triple the number of buses and sky trains and other public transit vehicles, you suddenly have a huge increase in ridership. People say, “I love taking the bus. It’s way faster and there’s so many buses and it’s so comfortable.” The buses will soon fill up.
Then, when all the buses are full again and the roads are empty, people will leave the bus and go back to driving. This back and forth will happen until equilibrium is reached.
Generally, the roads are always at equilibrium. There’s just the right amount of cars on the road. The roads are not busy enough to compel people to avoid driving, and they’re not empty enough to encourage new traffic.
Induced demand works in other areas as well. When air condition efficiency improved in the 1990s, more people bought and used air conditions.
When fuel economy in our cars improved, people drove more and used more gasoline.
This is why the government often fails when it tries to legislate environmental improvements. Subsidize the price of gas, and more people buy gas. Make cars more fuel efficient, more people will drive. Plant more trees and more people buy paper products.
It works in the opposite as well. Increased demand for hamburgers means people will breed more cows. Increased demand for fresh, drinking water means more desalinization plants.
This wouldn’t be a surprise to many people in the transportation sector. The more roads you build, the more traffic you cause. This is called “induced traffic”. Or, to be more general, “induced demand”.
“Induced demand is the phenomenon that after supply increases, more of a good is
consumed.” – Wikiepedia.
The idea that building more roads, causes more traffic sounds counter-intuitive at first. Let’s say the government builds 100 brand new roads in your city. Suddenly, there’s a lot more space for driving. People will say, “Hey, driving is awesome. There’s so much room! I’m gonna drive.”
Likewise, if you triple the number of buses and sky trains and other public transit vehicles, you suddenly have a huge increase in ridership. People say, “I love taking the bus. It’s way faster and there’s so many buses and it’s so comfortable.” The buses will soon fill up.
Then, when all the buses are full again and the roads are empty, people will leave the bus and go back to driving. This back and forth will happen until equilibrium is reached.
Generally, the roads are always at equilibrium. There’s just the right amount of cars on the road. The roads are not busy enough to compel people to avoid driving, and they’re not empty enough to encourage new traffic.
Induced demand works in other areas as well. When air condition efficiency improved in the 1990s, more people bought and used air conditions.
When fuel economy in our cars improved, people drove more and used more gasoline.
This is why the government often fails when it tries to legislate environmental improvements. Subsidize the price of gas, and more people buy gas. Make cars more fuel efficient, more people will drive. Plant more trees and more people buy paper products.
It works in the opposite as well. Increased demand for hamburgers means people will breed more cows. Increased demand for fresh, drinking water means more desalinization plants.
This is true, we learned all about this in economics class.
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