"When you tear down freeways, all the traffic just disappears"

[bandit957]

One must also remember that when the freeways were first conceived, we had only about 150 million people.  Now, about 70 years on, we now have about 320 million people.  That's an increase of 170 million people, or more than double what it was before the freeways.  So of course, there will be more traffic.  There's 113% more people here than there was 70 years ago!  These people need a way to get around, and more commercial centers to serve them adequately.

I don't think there's any more commercial "centers" than there used to be. The "centers" are actually now stretched along a loop around the edge of town - which forces people to drive further and create more congestion.

My area didn't gain many more people, but the traffic got a lot worse anyway.

[Duke87]

In theory, a congested 8-lane highway is better than an equally congested 4-lane highway; twice as many vehicles benefit from the 8-lane highway. The same applies in reverse, an 8-lane highway deconstructed to a 4-lane highway or a Boulevard may be equally congested, but fewer trips are being made. The question is if the non-highway advantages to a Boulevard conversion economically outweigh the losses from reduced road capacity (supply).

Indeed, you have hit on a key problem here, a sort of problem that negatively impacts a lot of discussions - we live in a world where lots of important matters require specialized knowledge to fully appreciate, so the discussion is always dragged in crazy directions because while the public is not really literate on the underlying concepts, everyone still has an opinion, and perception and reality can be staggeringly different.

In this case, the thing everyone perceives is traffic, and how much time they spend sitting in it. There is an assumption that if congestion does not improve, there has been no useful improvement, and if congestion does not get worse, there has been no negative impact. But that is looking at the matter from an entirely selfish perspective. If you look at it from a more societal perspective, indeed - a wider but equally congested highway still moves more people, as you say.

Now, this much is true - no urban freeway removal has ever directly resulted in ungodly congestion as detractors often predict it will. This is because, as has been discussed, most of the trips on the freeway are discretionary in their specific destination if not in outright existence. If I need to go to the store, I need to go to the store, but maybe if the fastest road to the store I like to go to is closed, I'll go to a different store. As to whether this is a good or bad thing, well, that is a matter of personal opinion. On the one hand, making travel down a specific corridor more difficult reduces people's practical options, and gives them fewer choices due to the reduced general mobility. From a perspective of personal freedom, this isn't a good thing. On the other hand, if the removal of the freeway reduces the overall number of vehicle miles driven in the area, an argument could be made that that is a major benefit for environmental reasons.

This is why the proponents of freeway removals, road diets, and the like are often derisively referred to as "anti-mobility advocates" - because, strictly speaking, that is true. If you advocate reduced transportation capacity, you advocate reduced mobility. But mobility does consume energy, so therefore reduced mobility equals energy is conserved - which is a benefit.

As with anything in life, there are upsides and downsides. Removing a freeway benefits some people and harms others. Building a new freeway does the same. Any given space can only be built up in one manner at a time, so no matter what is built there is an opportunity cost associated with it. Half a century ago the general consensus was that freeways were a highly worthwhile use of urban space. Today, that consensus has changed.

One thing I at least believe (in hindsight, mind you) is a major design flaw of our nation's freeway system is that as built it more often than not funnels long distance traffic directly through the downtowns of major cities. Bypasses generally do exist, but they are usually longer and therefore not the favored route (traffic congestion notwithstanding). This is a major weakness of a hub and spoke type freeway system. If we could erase the entire interstate network off the map and redraw it from scratch, it would make a hell of a lot more sense to design it the way several earlier toll roads were designed - the through route bypasses the outskirts of the cities it serves, traffic that wishes to head into town needs to exit and take a spur route, and traffic just passing through doesn't enter the downtown area and doesn't create any blight on the city. Alas, we didn't build things this way, and it'd generally be rather expensive to rebuild them this way.

[Mergingtraffic]

one of the reasons the freeways were built b/c of traffic congestion on side streets.  I-95 was built in the northeast b/c traffic on US-1 was horrible. People think the freeways created some traffic, there were traffic problems before the freeways.