News:

Thanks to everyone for the feedback on what errors you encountered from the forum database changes made in Fall 2023. Let us know if you discover anymore.

Main Menu

Induced Demand Debunked with one Chart

Started by kernals12, March 19, 2021, 07:26:10 AM

Previous topic - Next topic

kernals12

We're told that "we can't pave our way out of congestion" because people will just drive more and leave the roads just as clogged as before. But as this chart shows, that's false


We see that, nationally, the growth in driving far exceeds the growth in lane miles. And, the great slowdown in driving growth after 2007 happened to coincide with a period of increased roadbuilding.

And the idea never made a lick of sense. The road outside my house is empty most of the time, people don't drive down it just because it's there. And there are plenty of examples of new freeways removing traffic from surface arterials. And here in Boston, the Big Dig objectively has improved traffic, with the old Central Artery's mid day bumper to bumper traffic jams being cast to the ashbin of history.

Think of it like this. If a power company is experiencing rolling blackouts, do they just throw their hands  up in the air and say "If we build more powerplants and transmission lines, people will just use more electricity. It's hopeless!" No, they keep adding capacity as long as revenue covers the cost of expansion. Obviously, in many places, it would be prohibitively expensive, both in monetary and social terms, to pave our way out of congestion, but to claim we shouldn't widen our roads because it would just bring more traffic defies all reason, and is just the latest lie the anti-car crowd has rolled out as part of their nefarious anti-mobility agenda.


hotdogPi

I actually agree that induced demand isn't really a thing. Look at the southern half of I-495 (MA), which hasn't grown that much (the northern half connected large cities even before I-495 was there), and the northern suburbs of Atlanta, which have had huge growth despite the lack of an outer beltway.
Clinched, minus I-93 (I'm missing a few miles and my file is incorrect)

Traveled, plus US 13, 44, and 50, and several state routes

I will be in Burlington VT for the eclipse.

ahj2000

Agree- to a point. At some point, paving the 13th and 14th lane is a signal that other methods of decongestion may be necessary. Throwing in a rail line or some other high-capacity/quality commuter system is necessary when you have massive.

kernals12

Quote from: 1 on March 19, 2021, 07:37:11 AM
I actually agree that induced demand isn't really a thing. Look at the southern half of I-495 (MA), which hasn't grown that much (the northern half connected large cities even before I-495 was there), and the northern suburbs of Atlanta, which have had huge growth despite the lack of an outer beltway.

Highways are the only thing that are judged a failure when people use them. The guys at Streetsblog think empty streetcars are a better investment than bumper to bumper freeways.

kernals12

Quote from: ahj2000 on March 19, 2021, 07:48:13 AM
Agree- to a point. At some point, paving the 13th and 14th lane is a signal that other methods of decongestion may be necessary. Throwing in a rail line or some other high-capacity/quality commuter system is necessary when you have massive.

I made that point already

QuoteObviously, in many places, it would be prohibitively expensive, both in monetary and social terms

Also, each additional lane adds less to traffic capacity than the one before it, due to increased numbers of lane changes. So, if you have a 14 lane freeway, its best to split it up into local and express lanes, a la New Jersey Turnpike

hotdogPi

Quote from: ahj2000 on March 19, 2021, 07:48:13 AM
Agree- to a point. At some point, paving the 13th and 14th lane is a signal that other methods of decongestion may be necessary. Throwing in a rail line or some other high-capacity/quality commuter system is necessary when you have massive.

I'm also in favor of alternate route surface roads. For example, I-93 has MA 28 and MA 38, but the I-95 portion of MA 128 doesn't have any good alternates. Alternates don't have to parallel the freeway – if MA 114 (a diagonal) between I-495 and I-95 wasn't a straight line with no turns and a 45 mph speed limit (that's high for eastern Massachusetts), I-93 and I-95 would be more congested.
Clinched, minus I-93 (I'm missing a few miles and my file is incorrect)

Traveled, plus US 13, 44, and 50, and several state routes

I will be in Burlington VT for the eclipse.

kernals12

Quote from: 1 on March 19, 2021, 07:54:44 AM
Quote from: ahj2000 on March 19, 2021, 07:48:13 AM
Agree- to a point. At some point, paving the 13th and 14th lane is a signal that other methods of decongestion may be necessary. Throwing in a rail line or some other high-capacity/quality commuter system is necessary when you have massive.

I'm also in favor of alternate route surface roads. For example, I-93 has MA 28 and MA 38, but the I-95 portion of MA 128 doesn't have any good alternates. Alternates don't have to parallel the freeway – if MA 114 (a diagonal) between I-495 and I-95 wasn't a straight line with no turns and a 45 mph speed limit (that's high for eastern Massachusetts), I-93 and I-95 would be more congested.

Congestion on the I-95 portion of 128 is largely due to the antiquated cloverleaf interchanges, most infamously at I-93.

hotdogPi

Quote from: kernals12 on March 19, 2021, 07:56:27 AM
Quote from: 1 on March 19, 2021, 07:54:44 AM
Quote from: ahj2000 on March 19, 2021, 07:48:13 AM
Agree- to a point. At some point, paving the 13th and 14th lane is a signal that other methods of decongestion may be necessary. Throwing in a rail line or some other high-capacity/quality commuter system is necessary when you have massive.

I'm also in favor of alternate route surface roads. For example, I-93 has MA 28 and MA 38, but the I-95 portion of MA 128 doesn't have any good alternates. Alternates don't have to parallel the freeway – if MA 114 (a diagonal) between I-495 and I-95 wasn't a straight line with no turns and a 45 mph speed limit (that's high for eastern Massachusetts), I-93 and I-95 would be more congested.

Congestion on the I-95 portion of 128 is largely due to the antiquated cloverleaf interchanges, most infamously at I-93.

I think the congestion on I-95 at I-93 (I assume you're talking about the northern one in Reading), at least northbound, is actually because of the lane drop at MA 28 one exit later.
Clinched, minus I-93 (I'm missing a few miles and my file is incorrect)

Traveled, plus US 13, 44, and 50, and several state routes

I will be in Burlington VT for the eclipse.

kernals12

Quote from: 1 on March 19, 2021, 08:00:27 AM
Quote from: kernals12 on March 19, 2021, 07:56:27 AM
Quote from: 1 on March 19, 2021, 07:54:44 AM
Quote from: ahj2000 on March 19, 2021, 07:48:13 AM
Agree- to a point. At some point, paving the 13th and 14th lane is a signal that other methods of decongestion may be necessary. Throwing in a rail line or some other high-capacity/quality commuter system is necessary when you have massive.

I'm also in favor of alternate route surface roads. For example, I-93 has MA 28 and MA 38, but the I-95 portion of MA 128 doesn't have any good alternates. Alternates don't have to parallel the freeway – if MA 114 (a diagonal) between I-495 and I-95 wasn't a straight line with no turns and a 45 mph speed limit (that's high for eastern Massachusetts), I-93 and I-95 would be more congested.

Congestion on the I-95 portion of 128 is largely due to the antiquated cloverleaf interchanges, most infamously at I-93.

I think the congestion on I-95 at I-93 (I assume you're talking about the northern one in Reading), at least northbound, is actually because of the lane drop at MA 28 one exit later.

It's not. It's because of weaving. I've used that cloverleaf enough times to know that.

kernals12

Also, the town of Willits, California recently had a freeway bypass built to remove through traffic from Main Street. The induced demand theory would state that people would start clogging up the empty main street due to the added capacity, but local business owners say no, they, like almost all business owners in places that have been bypassed (radiator springs anyone), that the new freeway has reduced their traffic.

Rothman

I think "induced demand" is a lot weaker than activists make it out to be.  Look at Binghamton, NY or Duluth, MN/Superior, WI, where highway improvements have not resulted in higher congestion.

I've always maintained that economic health is really the bigger factor (i.e., people coming to an area for work) and that mass transit investments are complementary to highway improvements and not supplemental.
Please note: All comments here represent my own personal opinion and do not reflect the official position(s) of NYSDOT.

kphoger

And I think we need to define the terms carefully:  induced demand vs latent demand.
Keep right except to pass.  Yes.  You.
Visit scenic Orleans County, NY!
Male pronouns, please.

Quote from: Philip K. DickIf you can control the meaning of words, you can control the people who must use them.

thspfc

Quote from: Rothman on March 19, 2021, 08:49:51 AM
I think "induced demand" is a lot weaker than activists make it out to be.  Look at Binghamton, NY or Duluth, MN/Superior, WI, where highway improvements have not resulted in higher congestion.

I've always maintained that economic health is really the bigger factor (i.e., people coming to an area for work) and that mass transit investments are complementary to highway improvements and not supplemental.
I agree, it's important to remember that the areas that are getting major highway expansions are the areas that are growing quickly. Shrinking or stagnant cities don't need larger highways.

jeffandnicole

Induced demand is often an exaggerated issue, looking for the worst of the worst after a project is completed.  Let's say a road is jammed from 2pm to 7pm.  A lane is added, and now the delay is only from 4pm to 6pm.  Anti-road people will say the construction didn't work, and the road still clogs up.  True...except it's now only a 2 hour delay, not a 5 hour delay.  And many times, documents prepared for the project may even point out that congestion will still occur (possibly stated as service levels), so the project results are functioning as expected.

Some roads jam up at non-peak hours as well. The lunchtime hour can be hectic.  A road widening/improvement project can cure that significantly as well.

Also, traffic that was avoiding the jammed area, using back roads, residential streets, etc, may now go back to using the highway, seeing that they can use it congestion free.  The anti-road people aren't going to search around for the alternative routes people were using and compare them.


kernals12

There's a similar misconception in housing in the belief that new development causes home prices to rise.

HighwayStar

Quote from: ahj2000 on March 19, 2021, 07:48:13 AM
Agree- to a point. At some point, paving the 13th and 14th lane is a signal that other methods of decongestion may be necessary. Throwing in a rail line or some other high-capacity/quality commuter system is necessary when you have massive.

Why? There is nothing unique about the 13th lane that does not apply to the 2nd. All you might reasonably say is that rather than adding a 13th lane to that particular road perhaps another route would be in order.
But there are plenty of places on the east coast that would benefit from double deck freeways to remove congestion.
There are those who travel, and those who travel well

HighwayStar

Quote from: kernals12 on March 19, 2021, 04:12:54 PM
There's a similar misconception in housing in the belief that new development causes home prices to rise.

You hit the nail on the head, anyone with a background in Econ is familiar with this BS line of thinking. How about the one with the Tsar that discovered the providence of the empire with the most doctors also had the most sick people, so he had the doctors executed.  :ded:
The real key is that this type of explanation is not supposed to be correct, it is a means to an end, namely, forcing people to ride the putrid public transit. (nice signature on the profile btw)
There are those who travel, and those who travel well

hotdogPi

Quote from: HighwayStar on March 30, 2021, 01:18:01 PM
Quote from: ahj2000 on March 19, 2021, 07:48:13 AM
Agree- to a point. At some point, paving the 13th and 14th lane is a signal that other methods of decongestion may be necessary. Throwing in a rail line or some other high-capacity/quality commuter system is necessary when you have massive.

Why? There is nothing unique about the 13th lane that does not apply to the 2nd. All you might reasonably say is that rather than adding a 13th lane to that particular road perhaps another route would be in order.
But there are plenty of places on the east coast that would benefit from double deck freeways to remove congestion.

Bridges cost a lot more to expand than regular freeways. If the freeway expands to 13 lanes per direction, but the bridge is still 4 per direction, that's a huge bottleneck that won't be solved by adding more lanes to the freeway.
Clinched, minus I-93 (I'm missing a few miles and my file is incorrect)

Traveled, plus US 13, 44, and 50, and several state routes

I will be in Burlington VT for the eclipse.

HighwayStar

Quote from: 1 on March 30, 2021, 01:24:52 PM
Quote from: HighwayStar on March 30, 2021, 01:18:01 PM
Quote from: ahj2000 on March 19, 2021, 07:48:13 AM
Agree- to a point. At some point, paving the 13th and 14th lane is a signal that other methods of decongestion may be necessary. Throwing in a rail line or some other high-capacity/quality commuter system is necessary when you have massive.

Why? There is nothing unique about the 13th lane that does not apply to the 2nd. All you might reasonably say is that rather than adding a 13th lane to that particular road perhaps another route would be in order.
But there are plenty of places on the east coast that would benefit from double deck freeways to remove congestion.

Bridges cost a lot more to expand than regular freeways. If the freeway expands to 13 lanes per direction, but the bridge is still 4 per direction, that's a huge bottleneck that won't be solved by adding more lanes to the freeway.

Obviously, but that means you also do the bridge. And frankly I don't buy the cost argument unless you are doing something on the scale of the Chesapeake Bay Bridge Tunnel, if nothing else you can employ people to build as a form of public assistance.
There are those who travel, and those who travel well

kernals12

Quote from: HighwayStar on March 30, 2021, 01:18:01 PM
Quote from: ahj2000 on March 19, 2021, 07:48:13 AM
Agree- to a point. At some point, paving the 13th and 14th lane is a signal that other methods of decongestion may be necessary. Throwing in a rail line or some other high-capacity/quality commuter system is necessary when you have massive.

Why? There is nothing unique about the 13th lane that does not apply to the 2nd. All you might reasonably say is that rather than adding a 13th lane to that particular road perhaps another route would be in order.
But there are plenty of places on the east coast that would benefit from double deck freeways to remove congestion.

But pretty much none where it would be cost effective.

kernals12

Quote from: HighwayStar on March 30, 2021, 01:31:34 PM
Quote from: 1 on March 30, 2021, 01:24:52 PM
Quote from: HighwayStar on March 30, 2021, 01:18:01 PM
Quote from: ahj2000 on March 19, 2021, 07:48:13 AM
Agree- to a point. At some point, paving the 13th and 14th lane is a signal that other methods of decongestion may be necessary. Throwing in a rail line or some other high-capacity/quality commuter system is necessary when you have massive.

Why? There is nothing unique about the 13th lane that does not apply to the 2nd. All you might reasonably say is that rather than adding a 13th lane to that particular road perhaps another route would be in order.
But there are plenty of places on the east coast that would benefit from double deck freeways to remove congestion.

Bridges cost a lot more to expand than regular freeways. If the freeway expands to 13 lanes per direction, but the bridge is still 4 per direction, that's a huge bottleneck that won't be solved by adding more lanes to the freeway.

Obviously, but that means you also do the bridge. And frankly I don't buy the cost argument unless you are doing something on the scale of the Chesapeake Bay Bridge Tunnel, if nothing else you can employ people to build as a form of public assistance.

Most of the cost of building a highway is material and machinery, not labor.

HighwayStar

Quote from: kernals12 on March 30, 2021, 01:53:49 PM
Quote from: HighwayStar on March 30, 2021, 01:31:34 PM
Quote from: 1 on March 30, 2021, 01:24:52 PM
Quote from: HighwayStar on March 30, 2021, 01:18:01 PM
Quote from: ahj2000 on March 19, 2021, 07:48:13 AM
Agree- to a point. At some point, paving the 13th and 14th lane is a signal that other methods of decongestion may be necessary. Throwing in a rail line or some other high-capacity/quality commuter system is necessary when you have massive.

Why? There is nothing unique about the 13th lane that does not apply to the 2nd. All you might reasonably say is that rather than adding a 13th lane to that particular road perhaps another route would be in order.
But there are plenty of places on the east coast that would benefit from double deck freeways to remove congestion.

Bridges cost a lot more to expand than regular freeways. If the freeway expands to 13 lanes per direction, but the bridge is still 4 per direction, that's a huge bottleneck that won't be solved by adding more lanes to the freeway.

Obviously, but that means you also do the bridge. And frankly I don't buy the cost argument unless you are doing something on the scale of the Chesapeake Bay Bridge Tunnel, if nothing else you can employ people to build as a form of public assistance.

Most of the cost of building a highway is material and machinery, not labor.

Labor and capital are substitutes, you can use less capital and more labor. Furthermore I would not say "most", labor is always a significant cost, just not perhaps the majority cost. But even to the extent that neither of the preceding are taken into consideration, the fact that the project provides jobs still makes it a more effective use of funds than paying people to sit on the sofa and drink beer.
There are those who travel, and those who travel well

kphoger

Quote from: HighwayStar on March 30, 2021, 01:18:01 PM

Quote from: ahj2000 on March 19, 2021, 07:48:13 AM
Agree- to a point. At some point, paving the 13th and 14th lane is a signal that other methods of decongestion may be necessary. Throwing in a rail line or some other high-capacity/quality commuter system is necessary when you have massive.

Why? There is nothing unique about the 13th lane that does not apply to the 2nd. All you might reasonably say is that rather than adding a 13th lane to that particular road perhaps another route would be in order.
But there are plenty of places on the east coast that would benefit from double deck freeways to remove congestion.

Is the bolded statement actually true?  I thought I remembered reading somewhere that capacity improvement diminishes with each added lane.  That is to say, the improvement achieved by going from 2 to 3 lanes is greater than the improvement achieved by going from 4 to 5 lanes.  If that's the case, then adding a 13th lane would have very little benefit compared to adding a 2nd lane.
Keep right except to pass.  Yes.  You.
Visit scenic Orleans County, NY!
Male pronouns, please.

Quote from: Philip K. DickIf you can control the meaning of words, you can control the people who must use them.

HighwayStar

Quote from: kernals12 on March 30, 2021, 01:50:47 PM
Quote from: HighwayStar on March 30, 2021, 01:18:01 PM
Quote from: ahj2000 on March 19, 2021, 07:48:13 AM
Agree- to a point. At some point, paving the 13th and 14th lane is a signal that other methods of decongestion may be necessary. Throwing in a rail line or some other high-capacity/quality commuter system is necessary when you have massive.

Why? There is nothing unique about the 13th lane that does not apply to the 2nd. All you might reasonably say is that rather than adding a 13th lane to that particular road perhaps another route would be in order.
But there are plenty of places on the east coast that would benefit from double deck freeways to remove congestion.

But pretty much none where it would be cost effective.

Cost effectiveness is difficult to impossible to assess. Sure, its more "cost effective" to make people ride buses, but that is not the same level of service. To do any real comparison becomes difficult. Like it or not most of the infrastructure in this country was NOT built with an obsession over cost effectiveness, but with simpler metrics of success in mind. I would consider a dramatic reduction in the congestion on the coast to be cost effective, because nothing else is capable of providing that same result, REGARDLESS of what it costs.
There are those who travel, and those who travel well

HighwayStar

Quote from: kphoger on March 30, 2021, 03:11:05 PM
Quote from: HighwayStar on March 30, 2021, 01:18:01 PM

Quote from: ahj2000 on March 19, 2021, 07:48:13 AM
Agree- to a point. At some point, paving the 13th and 14th lane is a signal that other methods of decongestion may be necessary. Throwing in a rail line or some other high-capacity/quality commuter system is necessary when you have massive.

Why? There is nothing unique about the 13th lane that does not apply to the 2nd. All you might reasonably say is that rather than adding a 13th lane to that particular road perhaps another route would be in order.
But there are plenty of places on the east coast that would benefit from double deck freeways to remove congestion.

Is the bolded statement actually true?  I thought I remembered reading somewhere that capacity improvement diminishes with each added lane.  That is to say, the improvement achieved by going from 2 to 3 lanes is greater than the improvement achieved by going from 4 to 5 lanes.  If that's the case, then adding a 13th lane would have very little benefit compared to adding a 2nd lane.

You are correct in that there are decreasing marginal returns, but that is not the point being made. The point is that if you have some number of lanes where you tell people to go ride the bus instead that is entirely arbitrary. Your point is addressed by my second point regarding an alternative route as being more appropriate than a 13th or 14th lane.
Also note that the above assumes a true 13 lane wide freeway, which is not a good example because few roads are built that way. The Jersey Turnpike is a good example, it has I believe 12 lanes, but segmented to function as two 6 lane roads, which means that the marginal effectiveness of the last 6 lanes built is collectively the same as the first 6 lanes built.
There are those who travel, and those who travel well



Opinions expressed here on belong solely to the poster and do not represent or reflect the opinions or beliefs of AARoads, its creators and/or associates.