> The only way out of the trap AFAIK would be to build excess capacity thought the entire system.
I agree. This makes a lot more since.
The authors are taking good data, but making a big leap on their assumption to the cause.
Roads don't "create" traffic. New roads in most major cities are never built until the old ones are already 300-500% over capacity.
If you wait until your 500% over capacity, and then double the lanes, your still way over capacity, so the old and new roads are still "congested". This traffic isn't "new" -- it was always there, you just couldn't see it, because a 200% over capacity road, and a 500% over capacity road, looks like the same gridlock from the sky.
Except that roads do create traffic. Your line of thinking was exactly what drove NYC's road construction boom in the 40s and 50s - new road is built, utilization briefly goes down, then, as soon as people realize that there's now a faster, more convenient way to get into the city, they start using it. Utilization goes back up.
Critically, many of those people are people who might have taken mass transit or carpooled. They are literally new demand in the system driven by new capacity.
Over a longer time period, there's an even deeper effect, where new roads and perceived availability of road transit drives more people to move to previously undesirable parts of metro areas, which increases population which increases demand.
> Except that roads do create traffic. - new road is built, utilization briefly goes down, then, as soon as people realize that there's now a faster, more convenient way to get into the city, they start using it. Utilization goes back up.
That's not "new" traffic. Traffic was already critically underserved previously, and is now only majorly underserved. The original road was 500% over capacity, and now the new road lowers it to 300% over capacity.
>They are literally new demand in the system driven by new capacity.
No, the demand was always there. No one went out and bought a car because a new road was built.
These are people who we're already underserved by transportation previously, but weren't counted (because demand so outstripped capacity that they couldn't be easily counted originally).
> Critically, many of those people are people who might have taken mass transit or carpooled.
This is a huge assumption. For instance, this can only even be possible in a handful of places like Chicago or NYC. There is no meaningful mass transit in the most of the major US cities to even pull traffic from.
If public transit is a good option, people will take it regardless of how many roads exist. (Very few people purposely want to make life more expensive or more inconvenient for themselves).
> as soon as people realize that there's now a faster, more convenient way to get into the city, they start using it.
From what you've said, it sounds like your advocating for people to willingly make life more expensive and more inconvenient for themselves. Your saying "new roads make driving too convenient and nice, we should take roads out so driving becomes even more terrible than public transit already is. Force people to make a bad choice, to avoid a terrible one"
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There's absolutely no need to race-to-the-bottom on transportation. We should build more roads and build more public transit, simultaneously. When public transit becomes cheap and convenient, many people will willing choose it. For those who don't, new roads and additional capacity alleviates that problem as well.
Your logic assumes that driving is inherently bad, and that we should "punish" drivers as a result. That's terrible, there's nothing wrong with driving, and there's no need to punish people for driving. There happen to be some bad externalities to driving (exhaust, traffic accidents), but those problems are being worked on (electric zero-emission cars, self driving cars, etc)
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What your advocating for sounds really dangerous. Imagine if we applied this logic to any other market:
"The internet is congested. We can't just add fiber lines, if people had more internet speeds, they'd just use it up! We should destroy fiber lines, and cap all internet users to 1Mbps speeds, so that people start using the Postal Service and Blockbuster more often. "
"We can't run more clean water to the bad part of town. It might 'drive more people to move to a previously undesirable part of the metro area'. We should keep the water system broken -- or actually, just start slowly cutting water off to that area. "
> "The internet is congested. We can't just add fiber lines, if people had more internet speeds, they'd just use it up! We should destroy fiber lines, and cap all internet users to 1Mbps speeds, so that people start using the Postal Service and Blockbuster more often. "
Love this example. I can already see the wheels turning in some people who prefer a more centrally planned society.... Renting DVDs from blockbuster is more efficient. Each disc transported to an area enables hundreds of people to watch the movie. Sure they can't watch it on demand whenever they'd like, but the DVD rental model is so efficient. Sure, public transportation doesn't take you exactly where you want to go whenever you'd like, but its more efficient! (Yeah, the analogy isn't perfect, but it does make a striking point)
"There's absolutely no need to race-to-the-bottom on transportation. We should build more roads and build more public transit, simultaneously. When public transit becomes cheap and convenient, many people will willing choose it."
The problem with this is that roads take room, and have externalities (cutting up neighborhoods, noise, pollution). Some of these are being worked (as you note) but there are no full technical solutions to these problems. People won't stand for it.
For these reasons, your internet and water-use analogies are inaccurate parallels.
I'm surprised you're offering these arguments. I live in LA and the opposition to new freeways in already-built-up areas is pretty much ingrained at this point. (Conservatives hate the destruction of neighborhoods, and liberals hate the environmental consequences). Limited in-place widening is still being done (with complaints) but 50 years of experience have taught something of a lesson. People generally don't believe these wider roads will significantly lessen congestion.
> The problem with this is that roads have externalities
Public Transit does too. Cutting up neighborhoods, noise, pollution all happen with busses and light rails. The externalities are almost identical in either case. (You can bury your light rail, but you could also bury your roads, etc).
> For these reasons, your internet and water-use analogies are inaccurate parallels.
That may be true, but I don't see how yet.
People oppose fiber lines all the time because "telephone poles look ugly" or "I don't want to be in the electromagnetic field" (even though there isn't one).
> People generally don't believe these wider roads will significantly lessen congestion.
To be clear, I'm not advocating for bad roads. I'm advocating for more roads, and there is a big difference. New freeways should be far above ground (so that there's no division of neighborhoods) or below grade, just like new public transit (usually) is.
I'm also not advocating for more strip-mall like roads. (4-8 lane at-grade streets typical near malls, WalMart, etc). There should be lots of big freeways, with lots of small exits to smaller urban streets (downtown) or smaller suburban streets.
I think we are too far apart on this one. The buried freeway idea seems like a boutique solution for certain niche cases (the big dig in Boston is another example).
But the freeways relevant to me (in LA) are much too large and pervasive to put underground. It's over 100 miles of freeway, 5 lanes each way! And this is only in the most densely built-up core. Undergrounding them is lunacy!
By the time that all got done, we'd be in robotic helicopters or uploaded. Underground trains would be much more realistic (less tunneling for a given throughput), but even so, we have to be content with aboveground light rail.
>Public Transit does too. Cutting up neighborhoods, noise, pollution all happen with busses and light rails. The externalities are almost identical in either case.
Very true! However, they are significantly lower per person transported.
If people were rational you'd be right, but from happiness surveys we know that people underestimate the (negative) effects of a long commute by car. So it's entirely possible that when a new road is built, a family might move out of the city centre to a larger house in the suburbs, expecting this to make them happier, when in fact it makes them less happy.
> there's no need to punish people for driving. There happen to be some bad externalities to driving (exhaust, traffic accidents), but those problems are being worked on (electric zero-emission cars, self driving cars, etc)
They're being worked on, but they're not solved yet, and in the meantime US road taxes don't come close to covering those costs, and the way we treat road deaths as "accidents" (despite a larger, more predictable death toll than e.g. environmental pollution) means the compensation payouts are disproportionately low.
When you kill yourself because of a predictable risk it's on you. When you kill someone else because of a predictable risk that should qualify as negligent homicide, at least (and lower-risk things than driving do).
Okay, that applies to pedestrian deaths. But the vast majority of driving deaths are based on mutual choice to drive. As long as nobody's drunk it's rarely a 'kill someone else' situation, rather it's a 'two drivers interacted in a way that went wrong' situation.
Negligent homicide should not apply if the negligence was mutual.
That's not the whole picture. The article doesn't directly mention the economic benefits from more people being able to access an area. My guess is that it works something like this:
Let's say you change a 3 lane road to a 6 lane road, and double the capacity. While some people from nearby roads will decide to start using the new road, a lot of increased usage over time will come from the new development that's made possible by the improved capacity. Strip malls will open up, new subdivisions or condos will go in, business centers will open, etc. Which is all fine, but it means that ultimately road usage will increase until some pain-of-driving threshold is reached, at which it'll level out.
No, it doesn't. Why can't some of you understand basic economics?
For simplicity, let us have City Core (C), the suburbs reachable with a one hour commute at the worst (S), and the rural area/farmland (F) further out, and ultra-rural deliverance areas beyond that (D).
No one wants to go buy a piece of Farmer Joe's land in zone F and build a house when it takes 3 hours to drive to work. Therefore relatively few people live out there. Because so few live out there, many other people don't want to live out there (not much shopping, no entertainment, few schools, etc).
Now the road is widened. In C, it goes from six lanes to ten. In S, it goes from four to eight. In F, a new closed-access highway with four lanes is built.
What is the result? Why spend $650,000 on a house in S when you can build the same house in F for $300,000? Which is in fact what a ton of people do. Over a period of ~20 years, developers buy up the farmland in zone F, subdivide it, and build houses. People move for the cheaper/larger housing; businesses move in, retail is built, and now we have zone S'. You have four lanes of traffic from zone F connecting to an expanded eight lanes in zone S, which was originally four lanes. Can you spot the problem? Hint: 8 - 4 = 4. Thus the "effective" number of lanes is unchanged for the people living in zone S, even though we presume both S and C have increased density by building taller buildings, renovating to subdivide houses into apartments, etc.
Same for the people in zone C, where the four additional lanes of traffic from S' eat all the excess capacity from the expansion.
What was zone D becomes the new zone F'. Soon as they build some excess road capacity (damn hippies and liberals! what a bunch of Phooey, we should just build more roads) all our problems will be solved!!!
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So yes, in a place like NYC with massive over-demand for transportation, you are correct. But here in Dallas, we've been building tons of new roads all over for the past 50 years and it hasn't changed much, it has merely enabled people to buy up farmland and move further away. Plano in the 1960s was all farms, now it's been 100% build on (literally, the city has no further room to grow). Same for Allen. McKinney is almost completely built now. Any further road expansion will require tearing down skyscrapers, double-decking, or tunneling which magnify the cost of building new roads by an order of magnitude or worse.
Dallas is living proof that building more roads won't help congestion. It might lower home prices or allow your city to continue expanding, but it won't help with commute times or congestion beyond a small temporary bump.
I agree. This makes a lot more since.
The authors are taking good data, but making a big leap on their assumption to the cause.
Roads don't "create" traffic. New roads in most major cities are never built until the old ones are already 300-500% over capacity.
If you wait until your 500% over capacity, and then double the lanes, your still way over capacity, so the old and new roads are still "congested". This traffic isn't "new" -- it was always there, you just couldn't see it, because a 200% over capacity road, and a 500% over capacity road, looks like the same gridlock from the sky.