Well written and fairly convincing. Slightly off topic but the side point about highway capacity expansion projects interests me. I’m guessing it won’t be popular. But it’s true that more people are traveling and choosing to travel despite the congestion. I’ve never heard the urbanists so quick to dismiss such projects address these points.
The problem of the highway expansion is not damage done by the highway, or that the highway itself doesn't increase value for land far away: It's that the very subsidized highway later gives us horribly inefficient land uses which don't pay for themselves.
So yes, the widening of the highway makes the suburb more valuable, but the second effects make the city spend more resources on parking and makes the streets worse for anyone nearby. It's no picnic for the suburb either: A car-centric infrastructure basically bans anything else. That would be fine and all, if ultimately it produced more value than the alternatives. But look at the parking lots that were designed to never get completely full on black friday, back when it was actually a time where people did local shopping. Nowadays it's all wasted infrastructure, expensive to redevelop. If you thought that the commercial real estate office in dense cities was in trouble, don't look at the one in suburbs.
So it isn't really the highway, but all the things that relying on the highway leads to.
Not to mention how loud highways are. A concrete freeway generates enough noise at rush hour to make conversation impossible a quarter mile away. Nobody who lives nearby spends any time outside.
The issue from an urbanism perspective is not really that highways fill up immediately.
The problem is generally selling capacity expansion as "reducing congestion" when it does nothing of the sort. That, and the capacity gets used so quickly that you are very quickly spending yourself into a hole trying to build ever more highway capacity. The thing about a train is that it's very hard to make it so crowded the service degrades due to congestion, at least not within the first 20-50 years.
This black hole of money needed for highway congestion then starts pulling away from other municipal and transportation funding needs.
But that's true of public transit projects too. They always promise to reduce congestion and never actually do. Congestion charging is probably the only way to really reduce congestion and in many ways the solution is worse than the problem.
And, more than not being a problem, the highway filling up immediately is actually a benefit. Because more people are able and are choosing to travel, to accomplish whatever they need and want to accomplish.
Granted, the externality costs of all that car travel are high. But that's almost a separate issue and one that we really should be solving by a better accounting of costs and additional taxes. It's a shame that won't happen.
It doesn’t reduce road congestion but it does reduce transit congestion. The Second Avenue Subway, for example, decreased loads on the parallel congested Lexington Avenue line by 11%: https://www.6sqft.com/in-just-a-month-second-avenue-subway-e.... It’s displaced 88,000 trips a day, and yet it’s not anywhere near full; a highway expansion would struggle with that amount.
Traffic speeds generally have a floor of how long the equivalent public transport journey is. (If the public transport journey is faster, people will use that instead.) The issue now is that American land use is so out of whack it’s hard to deploy transit widely enough to make that true for the majority of trips.
I think you're on to something with regards to subways in urban environments moving a number of people that a highway expansion would struggle to match. Feels to me like movement of people should be the real metric and, given that, that we should be prioritizing transit investments in places like NYC, San Francisco, and West LA (as opposed to light rail to Azusa).
Downs-Thomson Paradox is also interesting here and relates to your second paragraph. In a built out environment, transit trips and car trips will take roughly the same amount of time, door to door. Transit advocates have used that finding as a way to complain about road projects, but I think it actually is a much more interesting finding that suggests a more multi-modal approach to planning. I wonder how relevant or irrelevant it is for non-built-out environments.
In the US at least, really the complaint from transit advocates is that funding is and continues to be overwhelmingly road-centric, with a small share for transit and basically a pittance for walking and biking.
Usually the issue with suburban transit investment occurring over urban ones is that urban areas are so weak they cannot fund expansions by themselves, and if you want the suburbs to pony up they’ll get their pound of flesh
It'd be interesting to think about ways we could implement congestion control on highways .. every thread I've read implicitly assumes it's not possible
Urbanists don't like highways because highways are generally sold to the public as a way to reduce congestion; what usually happens is the extra lanes fill up immediately. The capacity of a train is much larger and it's a lot cheaper to increase throughput on a train line (by running more trains, longer trains, etc) than it is on a highway.
Urbanists disagree that more VMT is inherently good. VMT is good because of why people make trips - see their family, go to work, shop etc.
The alternative isn't eliminating those trips. It's taking the trillions of dollars we waste and spending it on an alternative, more efficient modes that deliver better outcomes (travel time, cost, speed, comfort, etc)
I agree that VMT is good because of why people make those trips. If you're saying spending all that money on public transit would be a better way to help more people make more of those trips, then you'd be unequivocally wrong in much of the US. Go to someplace like Dallas and marvel at the nearly empty buses and light rail run cars. Maybe we could focus on dramatically improving public transit in someplace suitably dense like West LA. If only the politics allowed it.
Most people don't object to increasing rural highway capacity. However, the increased traffic has to go somewhere, and nobody likes busy streets in their neighborhood. Not in the suburbs, and not in the city. People generally want less traffic in their area, not more.
Urbanists tend to prefer walkable cities. They want to use less above-ground space for traffic and parking, leaving more space for buildings, parks, and public squares. Highway capacity expansions work against that, because they encourage more people to drive into the city.
Urbanists don't view the fact that more people are choosing to travel as good, because of the destructive effects of that travel (noise, pollution, parking, etc.)
I've lived in European cities and American cities. American cities are more car centric and its actually more convenient. Many cities in Europe are so congested and difficult to drive but its by design rather than a bug - it means people are more likely to get trains to get out of town. I do see that more roads encourages more cars and driving, I've found it to be a good thing.
Car dependency generally results in negative health outcomes though.
* driving is just less healthy than walking, biking, or walking to and from public transport
* driving causes high noise pollution and emissions; EVs will solve the latter but not the former, since above low speeds most of the noise is tires rolling against roads
* increased driving in the US has led to higher fatality rates for the people still walking and biking
* increased driving leads to lower funding levels for other types of transport since road infrastructure is so expensive, and not everybody can afford a car to avoid getting left behind
