Lol. You sound just like any other addict I’ve met.
Traffic is going to have a market value. If you live along a congested highway that takes 30 minutes to get into the city, you and everyone else that lives there has accepted that trade off.
Adding a lane might save you 10 minutes, but it also pushes that 30 minute boundary out 5 miles. More development will happen along that highway, and eventually that 30 minute boundary moves back inward.
It may not get back to the full 30 minutes while you are still commuting as this takes years of development to shift back, but it will happen.
Traffic is really a secondary benefit. Adding a lane will benefit those already living near the highway mostly by changing the land values, especially in a fast growing area.
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Adding lanes doesn’t relieve congestion because it will cause growth in use until congestion returns, sure. But it will serve more people overall. This isn’t an unbounded math problem on either side; n can’t be 0 or large. I think you are making a point that mass transit is the only thing that works. I agree, but only above certain densities.
Anecdotally, locally there is a major downtown/suburb connector that has heavy congestion at peak times. Three travel lanes each direction, constrained from going larger. They added a fourth lane in a few areas that connect short runs between access points with heavy inflow and outflow due to geographic features. This really improved the travel time at peak for the subset of people who use these routes, and helps the ones driving past with less merging traffic.
The interstate that is a similar downtown/suburb route has three lanes, but goes up a significant grade for 2 miles. The on ramp at the bottom at the start of the grade has a tight curve/short acceleration lane and folks try to merge at 25 mpg. It is a horrible old design. Adding a substantially long acceleration lane for the fourth lane going up the mountain would improve flow dramatically.
Demonstrably false. Go live in Switzerland for a year or two. You’ll not find many terrains less inviting for mass transit. Mountains separating small villages and hamlets. Yet…even tiny little towns get frequent high speed rail service albeit the terrain means a lot of very expensive tunnels.
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So this demonstrates it was the most economical way to serve the hamlets? I understand that it has consequences the Swiss either wanted or were willing to accept, but it might not be the same for the US.
On a side note, just because infrastructure has maintenance costs doesn’t make it a liability and not an asset.
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I would think uninhabitable terrain inherently increases population density of the habitable areas, as well as spreading them (pockets of population) out more. I don’t think it’s comparable to cities in terms of transit planning. Different problems imo.
Two spring immediately to mind. First is widening I-74 from two lanes to three in Cincinnati. That was done in the 80s and improved traffic quite a lot. The last time I was driving on it there was construction that was having an impact on traffic, but the portions of the highway unaffected by traffic were moving along pretty well.
Second is expanding a local road in suburban Portland, Oregon. Area was growing like crazy… with or without added road capacity. And while there is certainly traffic during rush hour… I shudder to think how bad it would be without the expansion. It’s a thoroughfare that runs between a lot of new-ish (21st century) developments and the train line, and traffic (not to mention parking) closer to the city is so bad that a lot of people are driving from their homes to the train station and taking the train into the city.
When you turn something on the order of 10 family farms into 10,000 homes… you need additional capacity on the thoroughfares. 
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Traffic can be a bit weird. There are a couple math “paradoxes” where adding a road or a lane theoretically does nothing or makes congestion worse. Hopefully they model it these days.
You are assuming the city continues to grow. If it doesn’t, the new road solves congestion for a long time.
Private autos and roads for them provide something that many Americans value – their own single family house on their own piece of property. If we all preferred high density and walkable neighborhoods, our existing communities would already look like that. Instead of the voters saying they wanted better roads, they would have said they wanted better mass transit.
Like many big cities, we have problems with homelessness and enough affordable housing for low wage workers. A developer proposed an affordable housing development in an area with a significant number of homeless people that neighbors complain about. It’s designed for people making under 12k a year, convenient to transit, and on site staff to help those making the transition from homelessness. The neighborhood voted overwhelmingly to block it, with some of the alleged main complaints being not enough parking there and too much traffic already.
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Adding lane-miles that compete with public transportation might well have that impact. Adding lane-miles that make it easier for people to utilize public transportation… I’m skeptical.
Also there has to exist decent public transportation for that to even be an issue. Portland has ok public transportation. Cincinnati has abysmal public transportation. About the worst you could possibly say about adding lane-miles in Cincinnati is that it might drive up demand by resulting in the city and metro area’s population (and tax base) growing larger. 
That said, every 20-30 years someone dusts off the maps of the maybe 60% complete subway system that hasn’t been touched in almost 100 years. If there were an honest debate about lane-miles vs subway completion there’s a lot to be said for completing the subway. But the only debate ever seems to be add lane-miles or don’t.
*shrug.
Some Issues:
- Devoting less resources to public transportation.
- Making public transportation less attractive to people.
- Making car commuting, in general, more attractive.
- Making the city more attractive, creating more density.
- Making highways more attractive than local roads (emptying the local roads).
The 5th is the weirdest, imo-- Braess's paradox - Wikipedia
But in short the fact that people have to label all these “paradoxes” and “iron rules” suggests that road building frequently doesn’t go as planned.
I guess they didn’t read the bit about transit.
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We have a giant multi-decade project happening here called the Beltline. An urban planner came up with the idea in his thesis. It proposes use of abandoned rail line, as has been done in many areas. He found enough abandoned track to encircle the inner part of the city (barring a couple of trouble spots), and proposed a ring of parks around the city with walking/biking trails and light rail. He also proposed lots of affordable housing, as many of these areas were cheap and blighted at the time.
It’s been slowly happening. First steps were clearing and putting gravel down on large stretches of the trail. People immediately started using them heavily. They then started paving stretches of the trail. It became incredibly popular, with mid rise development springing up from blighted areas. It’s absolutely packed on nice weekend days, filled with walkers, bikers, dogs, strollers, restaurant goers,… An amazing success so far.
Two things have been much slower though: affordable housing and transit. It’s done the exact opposite so far wrt affordable housing. Property values near the Beltline have soared, and rents near the more popular areas have skyrocketed. It’s one of the hot spots for younger folks to live. There is very much NIMBYism regarding affordable housing being built there now, and the fact that it’s taken so long put it out of reach in terms of development costs on much of the stretch. Saw a couple signs on a new midrise condo building protesting building another one right next to it. I got mine, screw the next guy.
Now some NIMBYs are trying to block light rail along the Beltline, even though it was ALWAYS in the plan for decades and in the referendum voters overwhelmingly approved. Now that residents near the Beltline have huge increases in property values and a trendy spot they want to reject all transit. The first stretch of transit along the Beltline would be in my general area, although I am not Beltline adjacent.
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That’s why I said alleged. People making under 12K in the city generally can’t afford a personal car, and generally would not consider it where transit is convenient.
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Yup.
Agreed. Better look at the revenues and any ancillary / externality costs while you’re at it.
Here’s pen and paper. Have a go. Many have done so and it always comes to the same answer…ISSUE MORE BONDS, we will catch up later.
You are being just a little too subtle for me here (which can be easy to do, admittedly). Are you saying the analysis/decisions were made poorly in the past, or it applies to all infrastructure, even high speed mass transit infrastructure, because all infrastructure is a liability?
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