Re-purposing one of the existing lanes (a bus lane can move more people than 3 SOV lanes combined). Toll roads, reinvesting parking revenue, and increased tax revenue from downtown land used for working, living, and playing instead of just storing automobiles.
I don't buy that it's not a useful concept. Space is limited in geographic areas so it seems like a zero-sum game to me. Adding more lanes means there is more space to be utilized by cars, taking away space to be used for other productive means of transportation.
The demand to travel is still there, as the author asserts, but it's how we use the space we have to provide it that matters. If you add another lane you induce demand for more cars since there is less useful land to build on for other purposes and you make it harder to get around by other means.
Adding extra lanes to a road just increases the amount of people driving on them, instead of easing traffic. So I would bet the same is true of public transit.
The point of adding lanes is not to improve commutes. It's to improve thoroughput. If you add more lanes, and traffic moves at the exact same speed as it did before, guess what that's a win. Your throughput is now higher, more vehicles are moving per hour, and that ultimately means fewer trucks clogging up the port across town (or across the country).
This is the case for all transit, known as induced demand. Increase the number of lanes on a road and you'll get as bad if not worse traffic than before as the increased capacity results in more people driving.
More lanes means a temporary decrease in congestion, which incentivizes people to choose automobiles as their primary form of transportation, which fills up the roads again. Repeat this cycle endlessly as roads are widened.
Basically widening roads doesn't decrease traffic in the long term. This is why LA and Houston and other car dominated places have wider roads than anywhere else and terrible traffic.
The core issue is that automobile oriented infrastructure infrastructure isn't very efficient at moving people in the first place. If you're going to spend a lot of money to increase transportation capacity, extra car lanes is a poor choice.
If a full lane is dedicated to buses instead then that bus would be much faster than the cars stuck in traffic, while moving significantly more people.
Is that dedicated lane cheaper? In many cities that are facing a traffic crunch, they've already made all of the "easy" road improvements -- for example, 101 in the SF Bay Area is pretty much all built in to the center median, so adding new lanes means adding outside lanes (which requires rebuilding every bridge and intersection).
It'd be cheaper, of course, to take an existing lane and convert it to a bus-only lane, but that's politically infeasible.
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.
If there's less congestion, doesn't that a) help with clearing the streets so that buses run faster, b) broaden ridership so it's not just "those people" on transit, and c) help get a larger body of the population lobbying for no-brainer improvements like dedicated lanes, shorter headways, etc?
I think adding more lanes is a mental trap. It seems like when you have a lot of traffic, what you need to do is add more capacity to your road. But that doesn't end up working the way you'd expect, roads aren't like pipelines, because a road network is not only capacity for transportation but a subtle system of incentives. It's easy to add capacity and lose throughput because you change people's decision making and reap results you didn't anticipate.
So, I would say, invest in a bus system to make better use of the lanes you have. Invest in a subway system to give people safe, cheap alternatives to car ownership. Change zoning so that people don't have to travel so far to get where they want to go.
These are all incredibly expensive, a subway is certainly more expensive than adding a lane, but they have the advantage of actually addressing the problem. Transport really matters and we need to pony up for it, and we'll reap the benefits for generations.
Great point that I hadn't considered before. Like how adding more lanes to a road just creates more traffic. I hope things don't go that way but I can see it happening.
There's a well known effect, called induced demand, where building more roads cause traffic to increase. Doing the reverse will decrease traffic, then transit won't have to scale up nearly as much as we might assume.
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