That’s because people are waiting too long on other roads! There is a point where traffic will not increase as all the demand has been sated.

That's not what induced demand is.

Imagine if there was a portal on your front lawn that allowed you instant access to downtown London. How much more frequently would you travel to London if it took you literally no time at all? All of those trips are induced demand--that is, it is extra demand that is induced by the ease of the trip. Shifting demand from one route to another is, by definition, not induced demand, since it already existed!

If this were absolutely true, the wide highways would be completely packed at 2am

Induced demand does not turn people nocturnal

Neither does it magically summon infinite traffic under all conditions

Every time you decide to delay a trip during rush-hour, because of rush-hour - that is an example of what you are describing.

As an example, in Bellevue, Washington - the evening rush hour starts (and is really bad) at 3pm - there are that many people leaving work progressively earlier that there is still a rush hour of people leaving work early to avoid the big rush-hour.

No. There is not.

You've totally misunderstood induced demand. You can build unlimited roads and they will all be used up and commutes will increase for everyone.

People engineer cities and development around transit. If you provide massive amounts of transit to a desirable location people will saturate it.

This is why initially highway projects look like successes. Wow. My commute is so much better. And then. In a decade. They're even worse than they were originally.

>People engineer cities and development around transit. If you provide massive amounts of transit to a desirable location people will saturate it.

well yes, that is the objective of building transit[0]: to get people where they would like to go. That people 'induce demand' by moving to a place where they can go where they would like to go with (initially) less friction is the system reequilibrating - from places where demand was not adequately sated[0].

Consider the opposite situation: we remove one lane from all highways, and drop the speed limits on all surface streets by 25 percent, and reduce the departures of all trains and planes by 25%. If adding capacity is bad, then reducing it must be good [for the economy and people's quality of life].

[0]If demand was adequately sated, where was it induced from? Adequately sated here might also be read as 'optimally sated' or even just 'less well sated'. Obviously there is a point where cost exceeds the marginal benefit, e.g. adding 10 new bay bridges would surely reduce mean transit times across the bay, but at a patently unreasonable cost-benefit ratio.

[1]Unless you like to argue that we are at the local or global optimum for transit capacity?

It's not that adding capacity is bad, that it can be ineffective.

Given that personal transport is such a large percentage of the nations' carbon footprint, adding more cars detracts from that goal. From that perpsective, or a localized pollution perspective, or people wasting time in traffic jams (because NO alternative exists) - those are bad things.

I've generally lived in places in the US where driving is the ONLY viable option. By adding lanes, an ineffective tactic, instead of investing in more scalable (ie: effective) solutions - therein lies a problem.

> well yes, that is the objective of building transit

The US traffic engineer currently tries to optimize for throughput as defined by vehicles per minute, rather than passengers per minute. Therein lies the rub. Take a 2 lane road, dedicate one for buses, and it turns out the passenger throughput per minute goes way up, a single bus can be equivalent to 50+ cars.

Which is all to say, build more lanes of road for single occupancy cars has a limiting factor for when that is no longer an effective solution to the transit problem. Yet, adding more lanes is often still the only solution applied in many jurisdictions.

in some cities where traffic was reduced in specific areas (usually the center), business went up, because, as more people were forced to walk, they also were more spontaneously entering shops and buying more.

You clearly misunderstand the concept of induced demand

This would only be true if additional lanes were built on top of each other instead of next to each other. As lanes are widened though they just keep pushing things apart and making other types of transit less pleasant, which will then create demand that wasn't there before (because people now need to be on roads longer to get where they want to go). There is a maximum density that cars can support that is LOWER than most cities are built up at.

But it will increase. People move farther away ("this commute used to be bad but now there's another lane so I can live in a bigger house further out!"), businesses build "enough" parking so things are spread farther apart, and all of this increases the miles driven, thereby increasing traffic.

No, there is no such point, because there is simply not enough room to transport every person in an office building or high-rise apartment building in a personal car to and from work.

More lanes only helps the car manufacturers. A nice train system up and down the front range would be great. Would also help people get their 10,000 steps in every day walking to the train.