Induced Demand & Roadway Widening: Everything You Always Wanted to Know (and Weren't Afraid to Ask)
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- Опубліковано 28 вер 2024
- State departments of transportation love to widen freeways. The Katy Freeway in Houston, I-35 in Austin...well, kind of any freeway in Texas when you think about it.
And there's no doubt that certain aspects of roadway capacity projects are futile -- basic microeconomics will tell you that when you increase supply, prices drop and more buyers show up. Or, in the language of traffic, when you add lanes, travel times drop and more drivers show up...until you reach a new travel time equilibrium.
But how many drivers? And do you just reach the same congestion levels again? If there's new traffic, where does it come from? And is "induced demand" even an argument you should be making? I mean...downtown business boosters LOVE the idea of more demand!
We look at how transportation agencies and their consultants analyze -- or don't analyze -- all of the possible sources of what I like to call Induced Traffic, and we'll get deeper than we probably should into the primary analytical tool regions use to identify capacity projects: the travel demand model.
Other CityNerd videos referenced:
- Exponential Traffic: • Why Traffic Congestion...
- Ginormous Interchanges of the US: • Top 10 GINORMOUS Freew...
- Tunnels: • Traffic Tunnel Pros an...
Resources:
- Noland, Robert B. (2001.) “Relationships between highway capacity and induced vehicle travel.” Transportation Research Part A, 35, 47-72.
- Cervero, Robert. (2003.) “Road expansion, urban growth, and induced travel: A path analysis.” Journal of the American Planning Association, 69:2, 145-163.
- Duranton, Gilles, and Matthew A. Turner. 2011. "The Fundamental Law of Road Congestion: Evidence from US Cities." American Economic Review, 101 (6): 2616-52.
- Mokhtarian, Patricia L., Francisco J. Samaniego, Robert H. Shumway, Neil H. Willits (2002) Revisiting the Notion of Induced Traffic through a Matched-Pairs Study. Transportation 29 (2), 193 - 220
- www.bloomberg....
- www.vox.com/vi...
- www.thestar.co...
- www.chron.com/...
- Portland Comprehensive Plan: www.portland.g...
Image Credits:
- Atlanta traffic clip Video by citi-flix from Pixabay
- LA traffic clip Video by Ronald Brown from Pixabay
Music:
CityNerd background: Caipirinha in Hawaii by Carmen María and Edu Espinal (UA-cam music library)
Twitter: @nerd4cities
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What also needs to be taken into account is the fact that most of this added volume goes to downtown regions, so now more parking spaces and lanes are demanded. That’s how you turn what should be the heart of a city into Dallas-Fort Worth
You also have to take into account that destination roadways or exits may already be near capacity, and while the highway may not be as congested, the destination roadways might be, leading to worse congestion than before. You might save 10 minutes on your highway trip, but add 15 minutes at highway exits or destination arterial roads.
There are also environmental, societal, health, and tax efficiency consequences that are all forgotten. Car travel and car traffic have so many nuanced problems that it's hard to discuss with normal everyday people the numerous problems that car oriented urban areas cause. People are only starting to car because of people like City Nerd and Not Just Bikes but also because car oriented land use has hit its peak, in all the aforementioned consequences. People are thinking more about the environment, more about our society, more about their health, more about the lifestyle they want to live, and more about the absolute shitshow that cars and parking lots are. Not to mention the immense cost of all this.
I was already way over the time I wanted on this video, but yeah, the spillover impacts of increased traffic or really far-reaching and horrendous. Maybe a future video.
@@PSNDonutDude I'm a native of the DFW area and it's a hellscape under constant and inefficient construction that ultimately makes things worse. The State Longhorn should just be made of sculpted traffic cones
Hello fellow Dallasites. It’s a Love/Hate relationship here for me.
Yup and this is also where park and ride can help. Using park and ride to alleviate your freeways while creating rail that is solely based on this type of commuting (see go rail videos from NJB) is probably not great. But using park and ride to keep cars out of the city center is great.
“Orthodox Urbanist teachings require you to be anti-park-and-ride too”
Thank you for continuing to spread the good word!
@@JacobGadzella Mass transit conveys the most benefits to those who cannot drive a car, think those with disabilities, children, or senior citizens. Park-and-ride is basically the worst of both world because they REQUIRE you to drive to use public transit, basically exclude population that can benefit the most, while still induces traffic surrounding the sites.
I joke, but it is pretty bad. I mean how do you want to use incredibly valuable land around a high capacity transit station? Housing for people or housing for cars?
@@CityNerd In toledo, ohio we have a park and ride/bus transfer area that occupies part of a walmart parking lot
Nothing wrong with park and ride to keep cars out of your city center. Plenty of parking close to city centers that rarely gets used on normal days (e.g. football stadiums such as Amsterdam Arena P&R). But using park and ride to keep cars off the freeway is problematic. It creates situations like NJB explains in his Go rail video where you have train stations out in the middle of nowhere that can only be reached by car and that have swaths of parking surrounding them. This is bad because you should really build transit oriented communities around train stations.
Park and ride is ok in small doses. But building train stations in a sea of parking lots is dumb.
I'm reminded of a comment about road expansion that described it as "after months of noise, delays, and confusion, the previously existing traffic jam is relocated by 1/2 mile."
It's a depressingly frequent outcome.
And these projects cost in the billions. People can malign transit projects and their overruns all they want, but governments are spending billions to add a few lanes for a few miles. It's insane. A billion dollar project like the green line in Boston may be overpriced, but it's definitely a far better value than a highway widening.
If only these construction projects took 1 month..sometimes they take years
The lesson I've taken away from looking at induced demand is that it's not really good or bad. As you say, "induced demand" can mean more customers for business or residents for landlords or developers; they want it, and truthfully, anyone interested in growing a city's population should be, too. The problem is capacity: you create a lot more capacity with pedestrian, cycling, or public transit facilities per unit of space consumed than you do with roadways. I think that's an important point to bring up to those parties interested in inducing demand. Public transit can, hypothetically, induce a lot *more* demand than cars can, because it takes a lot more people to fill a bikeway, bus, or train than it does a car.
The problem is poor town planning - adding capacity ad-hoc without a good plan or building code leads to a town centre that nobody enjoys and is ripe for losing all those customers when someone opens an out-of-town shopping mall.
e.g. 1:48 for two points of view on the same effects.
@@williamchamberlain2263 That is EXACTLY what happened to the town I grew up in. Luckily over the last few years there's been some changing of the hands of power and some reinvestment has been done in the downtown area, as well as other areas outside of town that have similarly deteriorated, and things are slowly but surely coming back. More locals own small businesses downtown now that at any point in the last 30 years, and increased enrollment at and investment by a local college has helped create an entirely new customer base to cater to which has REALLY helped bring life back to downtown.
@@driley4381 good idea to include young people in it
I’ve loved these refreshing takes on induced demand. As Oh the Urbanity would say, “what kind of demand do you want to induce?”
"All models are wrong" is a saying you'll hear sometimes in traffic engineering circles. :) My region is adopting an activity-based model to replace the 4 step model, but I am still learning about it.
It amazes me that the standard practice is to generate a single forecast based on a single set of assumptions rather than some sort of Bayesian/probabilistic approach.
@@CityNerd Good point on this. There is work to apply models to show results as a distribution. ABMs have far fewer broad assumptions and are much more flexible in showing the effects of specific changes like tolling and special lanes.
The longer saying in science is "all models are wrong but some of them are useful." :D
As a committed strong town individual, I really appreciate the detail that you went into in this analysis. It's definitely complicated, and I appreciate some of the lane expansions in SoCal, but the lack of any real option for public transport in the sprawl makes lane expansions a 100% given in the current models. More fundamental items need to be changed and lane expansions will continue to be part of that mix, although I hope that the need for that decreases over the next couple of decades in the greater SoCal area.
Eyyyyyy shout to a fellow San diegan SoCal is so car dependent it’s the saddest thing
I live in Houston. Thanks for doing a great job of explaining how traffic engineering works. I'd like to explain Houston's "Katy Freeway" (I-10) induced demand issue that so many people bring up. While in many cities induced demand happens from the 5 different causes you highlighted, in Houston, the lion's share of the induced demand was from Katy, Texas (a western suburb of Houston) and Houston growing so fast. From 2010 to 2020, Texas grew faster than any other state, we added 4 million new residents in 10 years according to the US Census Bureau. The Houston metro area added just over 1 million people in that time, bringing us to 7.4 million, the nation's 5th largest metro area. The Katy freeway does not have nearby useful large arterial roads that drivers were previously using, and sadly, it also lacks meaningful public transit of any kind, and woefully lacks useful rail services. So there was little to no spillover from alternate routes when the freeway was completed in 2008. In 2008, Katy, Texas was a much smaller bedroom community compared to the large city it is today. Remember from 2010 to 2020, Houston metro added just over 1 million people. So in this case, induced demand was from new residents moving into the metro area who were not here previously. ------ What I'd love to get help with is figuring out how to get HGAC (the regional transit planning authority) to add in regional commuter rail and some meaningful metro rail or light rail for the higher density areas of Houston. So far, my efforts have fallen on deaf ears despite being an engineer that does work with TXDOT on various projects. 1 of the other problem we have here that you previously mentioned was that while most cities have 1 downtown area that people are trying to get in or out of during rush hour, Houston has it's large downtown, but then also has multiple "edge" cities, with 7 that contain at least 10 buildings higher than 100 meters along with lots of smaller buildings. Each one of these have their own rush hour flows as well. Bad planning in my opinion, but fixable if we institute commuter rail and other transit options. I'm not trying to take away cars and trucks from the freeways, just provide alternatives for those who would prefer different transit options. Despite Houston's lower density urban sprawl makeup, I think there are enough people that would use regional commuter rail willingly and without incentives, that it would free up some space on our freeways. Any ideas how to get this started?
I think that as far as pitches go, "providing alternative modes for those who want them" might be a slightly easier sell than "rail reduces freeway traffic," which might be hard to prove, and is not really the main reason to do it anyway.
tl;dr
Katy Freeway is the poster child for "induced demand" but people seem to leave out that half of the expansion went to building toll roads. And the problem with the toll roads is that they exit right back onto the friggin' freeway! So there's virtually no benefit unless you use the toll road and the next available toll exit is close to your intended exit. The pricing on the toll roads is also ridiculous...there's one stretch from beltway 8 to barker cypress that charges five bucks for a whopping six miles; needless to say, the toll road is usually empty.
@@Burt1038 I agree, I don' t think the toll road in the center should be considered a competent of I-10, however, I-10 is not the victim of induced demand in the way city planners are talking, but instead the victim of regional population growth beyond what was predicted. The Houston metro area grew by just over 1 million from 2010 to 2020. At the time I-10 Katy freeway was designed in 2005, the estimates were for the Houston areas to grow by just half of what it did according to H-GAC, the regional transit planning authority. So I-10's congestion is more due to failing to plan for the realistic growth which is new residents moving to the metro area from outside of it rather than induced demand which is existing residents now deciding to take the freeway. What could have helped, is with all the space in the center of the Katy freeway, to put in some type of commuter rail to give people some options.
So basically what you're saying is the induced demand was due to reason 5 which he mentions while introducing the topic.
I would posit that the Katy region would not have seen as much new home construction and population growth had the Katy freeway not been expanded.
So the highway induced demand in the long term because it made Katy an "attractive" place for people to sprawl out to from Houston.
This is super nerdy but I love how in depth you get on the actual process for measuring traffic dynamics.
Got me thinking: I'd love to see a video on top 10 (of course) cities ready for new/expanded rail systems based on the current transportation system i.e. highways, arterial roads, population density, and avg vmt and commute times.
Interesting idea. Thanks!
I've been reading Confessions of a Recovering Engineer and it gives a pretty dismal impression of the state of traffic engineering as a profession in North America.
Then you may also find this take on it... well, if not enjoyable, then at least validating: ua-cam.com/video/8oq0u2i4iHc/v-deo.html
is this a book? do you have a link where i could find it? thanks!
@@skythewonderdog uhh… amazon?
So much has been left out.
General rate of car ownership is rising as well as number of miles traveled.
The amount of lane changes and how much trucks run on the road haven't been considered here.
How many on and off ramps and of which capacity are on the highway. The travel speed and speed differential is important too.
Updated the comment a little bit.
I enjoyed your video, and I got a bit of a kick out of seeing my home city of Perth being used as the image for traffic congestion!
Ironically, the section of the Kwinana Freeway you chose to use is actually one of the most constrained and fixed sections with no further widening possible. They caused environmental destruction to reclaim land from the river to build the freeway in the first place and are likely to never get approvals again to add more lanes.
Further south and away from the city, this freeway has been widened continually and yet I don't see great improvements in travel outcomes. All it has done is move the bottleneck further down and encourage more people to drive.
I also got a nice kick out of that image. I think Perth is a great example of a sprawled car-dependent city that needs a serious rethink of its approach to transit.
@@AlexanderRafferty I think Perth is a really interesting city from a transit perspective. It is clearly a 1950s planned city that was designed for urban sprawl and car dependency, and yet it has generally fantastic cycling infrastructure and public transport that, in spite of its excellence, is still not chosen by the majority of people who would rather be in bumper to bumper traffic for whatever reason!
Great video. It's also worth mentioning that if a city has a growing population, then traffic congestion will get worse if nothing is done. A lot of the extra traffic when a road is opened is actually extra traffic due to population growth that would have increased congestion on other roads.
... induced demand means "successful better jobs"... More lanes drops travel time so people can take that better job a bit further than before... From 1900 we went from only working at jobs within half hour 2 mile walk, to trams in 1930 allowing 5 mile in half-hour, to cars allowing 20 miles in half hour. We increased using pir2 the area to work in from pi4 to pi400. Wow.. Cars are sooooo helpful they allowed job specialialization.... Even in W Europe 75% of workers drive to work, cars allowed modern job market, google France Statista How Workers Commute...... Yet transit UA-camrs skip numbers... US lacks dense European cores so cars will always be 90% car... Europeans choose cars too, walking and waiting in cold rain 6 months suckkkkkks.... P.S. we induce demand when build hospitals, let's people get care for minor issues, induced demand is good, letting more use a thing is good!!
Should transportation planning even be done at the project level? Moving towards a more general comprehensive approach to transportation planning would allow people see the issue of congestion at a more holistic level and in my opinion, an issue of capacity. An issue which, is better solved by changes to networks instead of streets, to mode shifts instead of road expansion.
Interesting that you've used an imager of a PERTH Freeway as the background to many of your data points here. Several of Perth's major freeways like the Kwinana Freeway pictured above could have added additional traffic lanes and even a Traffic "Tidal Flow" lanes were proposed whereby Central lanes would reverse depending on peak traffic times. Fortunately the central median was given over to TRANSPERTH in order to increase the cities rapidly growing Urban Rail Network.
So a win for Trains - yeah!
"Proposed"? It happened! I'm now wondering how many people even remember the bi-directional peak lane that existed before the Narrows duplication...
The Canadian cities of Vancouver and Victoria actually had always operated under the commitment not to increase vehicle capacity since the late 90s. As a result, traffic volume has remained steady or decreasing even after narrowing more roads and significantly larger population.
Those SkyTrain extensions can’t happen soon enough, though.
"Don't build it and they won't come"
As a fellow Vancouverite, that's sorta true and sorta not true. There is a *lot* more traffic now than there was 20 years ago, and it's particularly noticeable on each of the bridges south of the Fraser and on the North Shore. For most city streets though, it's about the same. As lies damnlies pointed out though, the Broadway, Surrey, and even North Shore extensions to the Skytrain can't come fast enough.
I would love to see a video highlighting a case study of highway widening not working, or maybe the history of TX or CA freeway expansion. Great stuff every video!!
Thanks for an in-depth and interesting video. I've always been wary of the idea of induced traffic but I like this analysis. I note that sources 1, 2, and 3 are preexisting trips. 4 might happen with discretionary traffic (e.g. mall) but not non-discretionary (most employment, and employment commuting is what creates rush hour). I expect pretty much all long-term negative effects of capacity planning are due to source 5. It is frustrating that when land use is so heavily regulated in the US we can't get this right. But this does mean that the road itself doesn't directly generate additional traffic.
Here's a hot take. Any road network was probably fine when first built, and then development grew beyond its capacity - an argument that roads themselves are not a problem, and if capacity and other development happened hand in hand traffic would stay under control. Adding a lane adds capacity but it is still finite, it is not a cure if you can't keep demand in check. (I am ignoring the land use efficiency argument here, but that is different from the induced traffic argument.)
Which leads me to my second hot take. The real failure is lack of coordination of development (traffic capacity vs demand, regardless of mode), and local control ruins city planning in the US. Cities should not be balkanized rivals able to have their cake and eat it too. Many urban cores are anti-road and want everyone to be urbanist like them, while at the same time not zoning enough housing to let people live near jobs. Simultaneously, suburban voters sabotage attempts to build regional transit systems.
I'm curious about induced demand in locations that are either not growing or actually losing population. My anecdotal experience is that stagnant cities and shrinking cities in the US have much better traffic than rapidly growing cities, in fact, growth seems to be the most important factor for traffic congestion outside of the 3 largest metro areas, which are so large and congested that they are in a different category. Maybe a future topic? Correlation of metro area growth with congestion?
Do a video on Wisconsin and their lack of transit outside the Madison and Milwaukee area. They are so concerned with those two cities but forgot about the rest of the state.
just seeing this now. just wanna give you credit. i cannot believe you got 76k folks to watch an 'induced demand' video. wildly impressive.
Knowing that you are(/were?) a traffic engineer perfectly explains your deadpan comedy and monotone content delivery lol. I thoroughly enjoy it though.
For a suggestion: I’d like to see a video covering bike lanes, sidewalks, shared use paths, and when it’s typically best to use each one.
I feel like this video would have pre-empted Economics Explained's video about induced demand if he had seen it. You do such a great job of addressing EE's exact problem, that "the demand is always there, you don't create it from nothing", while also explaining that that's just a problem with terminology. And you then give us the nerdy evidence that the actual point remains true: adding lanes adds traffic, and the solution is more non-car transit. You accidentally made a killer response video, a year before it was needed!
I am in Delaware and "induced demand" with DelDot has not happened as much as roads were built out after growth occurred without the infrastructure in place when residential developments were zoned. The issues with DelDot has been the amount and length of projects on the same roads.
i really enjoy your calm and educated takes on these topics, especially now that they have become more popular to the public(thankfully).
you see too many amatuers talking passionatly about these subjects, thinking they know more about theem than they are, it can hurt the new urbanist movment in the long run, since the movement's most popular points would be based on shaky ground.
Thank you for mentioning the seemingly nonsense use of demand, especially those with economics background (e.g. me). I have a passion for economics, and having first heard the term, I immediately wanted to call nonsense on it because adding supply does not shift demand. I agree people really should call Induced Traffic.
Finally a great explenation about the topic! People just said it time and time again without a great understanding of the actual meaning.
It's also worth pointing out that because traffic follows the supply and demand system, traffic is only ever as bad as people are willing to put up with. Every day there are thousands of people that choose not to travel because of the hassle of traffic, and as soon as the disadvantage of sitting through traffic is less significant then the benefit gained from traveling in it, people will choose to drive. Same goes the other way, if people have a choice other than driving and you make a road significantly more congested (due to narrowing) people will choose to take other options rather than sitting in traffic. The important things is that there are other options and no one is forced to sit in traffic because there is literally nothing else they can do.
There really is basic math at the root of all this, as much as it appears to be randomness moment to moment.
I think a great benchmark of understandable for a video like this is if a new traffic engineering intern could follow & explain the slides without the audio after a little practice. My guess is that this is practically there-great work!
This is probably a video I will have to re-watch several times. In school we did not get this in depth about induced traffic.
I got an answer to traffic. Move over after you pass someone not matter what lane you’re in. Obviously not but the US loves going the same speed in every lane holding up miles of freeway all for 100’s of cars to try and pass everyone in the fast lane. Then it’s basically open freeway after you pass the group.
I would love to go beyond what you rightly say is not induced demand but the graph for supply / demand curves will show how more people will drive when another lane is added to a congested highway. Demand really does exist and it does get encouraged by different approaches. They may include:
Car Culture: when we believe we need a car for our job, for prestige, for personal satisfaction, we get one.
All that Advertising: When car makers spend top dollars on ads, they do it for a reason, it works at least to some extent.
Travel Route Capacity: What people quote when they talk about induced demand. It's great to notice relieving bottlenecks at one part of a journey can reveal bottlenecks somewhere else in the city.
$ Cost: I noticed many people take the bus because they can't afford to drive but when they get more income they drive. Many who don't drive are just waiting for when their finances change and do prefer to drive if they could afford it.
Great episode! Love these explainer type videos!
great video! There is an obvious relation between road capacity and VMT for all, so environmental argument ultimately supports transit projects.
There's a major junction near me that has had at least four significant "capacity improvement" schemes in the 20 or so years that I've been here. Each time the council suggest a new scheme, I ask "when is this junction going to have *enough* capacity?"
Something I feel like I never see mentioned also is that driving on 3 and 4 lane freeways feels significantly more dangerous than driving on 2 lanes where I really just need to keep my eye on the passing lane and ramps.
2:30 - I never understood this graph at all, until I saw the Steam marketplace's breakdowns on item prices and item orders. They had the axes reversed, and it finally clicked for me.
I like this video. I dont have much to say, but I want to post a comment to help feed the algorithm, and create Induced Views. All hail the machine.
Thanks for the technical breakdown!
"A hidden bottleneck", or, you know, a bleedingly obvious one. A city I used to live in in Australia widened one of its bridges, which lands right on the edge of the city centre. It changed from a two lane bridge to a four lane. That four lane bridge landed on a two lane street. Instead of two lanes of slow moving traffic as cars filtered into the CBD, it turned into two empty outbound lanes, and two inbound lanes of choked traffic, with people waiting in queue, on the bridge for two or three cycles of the lights to get through the intersection at the foot of the bridge.
Thanks for this nuanced look at the problem. You've cleared up some of my naive misconceptions.
Well done - a side note could be on how these same weaknesses (in the analysis tools) can over-estimate the severity of congestion when a traffic lane is taken away to build transit or bike lanes.
I also like your point that traffic engineers are criticized unfairly. Your channel takes a fair tone - contrary to the hatred and scapegoating, most or all traffic engineers these days mainly want safer roads, protected bike facilities, traffic calming, lower speeds, and optimizing traffic but in the context of the best solution for all users. And are also appalled at the difficulty of getting these things done.
Good comment. The traffic/transportation engineering profession is constantly evolving, but there's definitely an "old guard" that's aging out and being replaced by engineers who have grown up in a different world and -- I think -- had an education that really emphasizes context sensitivity. Not to be ageist about it -- some of the most forward-thinking engineers I've met have been around the industry for 30+ years, but in general, the dynamic seems generational.
To me induced demand also means people doing something because you force them to. So like everybody who lives in one of these places where "you really do need a car" either has a car or is trying to get one. The other means of transportation have been removed so there's no other choice. And highways increase that situation because they do actually create places where you can't walk or bike or take the bus through. So that's another meaning for induced demand.
The problem of congestion begins with the necessity of going from point A to point B. When you get those closer together, other forms of transportation become more logical. Build schools, shops and businesses, restaurants in the places where you live. Then you can walk or take a bike. You now have decimated the miles you need to make. Kids can go to school without the need of a car, groceries don't take an hour to get to the store and back etc.. Use al the billions that are now used for highway expansion, to create a viable and safe infrastructure for cyclist and pedestrians. Make sure there is a variety of public transport options when distances are much further than 5 miles. Make bus lanes so they can follow a predictable schedule, and don't get stuck in traffic as well. In the US gas prices are ridiculously low, increase taxes on fuel to help pay for these changes., but also to induce economic incentive for using other forms of transportation than a car. And than, when you do have to, or want to use the car you than will not get stuck in traffic on a road half the size, and with half the maintenance costs.
I just had a video idea. This concept of induced traffic but related to transit ridership, capacity filling up, or not, when a transit operator increases capacity with more frequency or new routes.
Wow this is, like, no shit analysis with a real model and real parameters. I feel like I’m back in Grad school all of the sudden.
Fantastic!
How cities solve congestion in my area:
Take a freeway thats three lanes. Remove one lane and make that lane a pay to use lane to make traffic worse and encourage people to pay the state money to use a lane.
Thats what they do in Colorado.
Thank you for this explanation. I thought I knew enough about induced demand...
TxDOT is working on the exception which is more lanes on I-45 out of Galveston to the rest of America because that’s basically the only (real) road off the island
Nice breakdown of everything I definitely learned new stuff from this short video!
The poorly understood situation is that pressure on employers to employ as few workers increases each year, and means that workers need a lot of expressway mileage to move to a wide variety of jobs within an hour driving circle centered on your house. However, I worked in aerospace, and am aware that what best can be called flying cars are coming down the pike a lot faster than most of us would believe. That will introduce a situation in which workers will have the option to live anywhere in a state, and commute to a job. You may not have noticed this trend, but it is growing in momentum. Some of the technology is classified, and that is why it is not publicized.
Thanks for doing this video. There is a lot of misinformation out there. We should look at induced demand as part of the full transportation system. Demand for transport, as in the economy, to travel from A to B is a good thing. The question is how as a society do we facilitate as much of this demand as efficiently as possible, and in a sustainable way? I do support highway widening and there are widening projects near me that have reduced congestion (3 lands up to 4). But it should be seen as one of a range of measures. I like the idea of congestion pricing in some ways but I feel a bit guilty, I am rich and I'd be happy to pay £15/day (~£5k year) like as in London to be able to drive around my city with less congestion but I know that by doing this I'm pricing poorer people out of road use and the same economic opportunity I enjoy.
A lot of poor people drive because they have no other option. Congestion pricing in a city like New York or in the other NE cities wouldn't disenfranchise poor people because there's transit options available. The people driving in NYC are typically all rich anyways. In terms of like a city in the south or Texas, there's not that same robust transit network.
Also highway widening is fine outside of cities, but we shouldn't have highways inside cities to begin with. If you're someone who's from the suburbs of course you're going to support a project like that, but projects like that ruin our cities and make them ugly and polluted.
Very useful video! One element you allude to but might expand on is how expanding one road will influence other roads. It's sort of an extension of your note about pinch points.
I might do something more expansive looking at networks, but it's really hard to do it concisely.
"Induced demand" is EXACTLY economics (~3:00). Think of the time/convenience of getting from A to B as the "price" of driving from A to B. If you lower the price (decrease driving time, increase convenience) of driving from A to B, you will create more demand for driving from A to B. Lower price of a product increases demand for that product; not the other way around. So induced demand is in fact simple economics. This is also exactly why public transit in most cities is designed to fail, because driving from A to B will always be faster than using transit to get from A to B, thus transit is always relegated to people too poor to afford driving and becomes neglected. The exception are small city cores in places like Montreal, where you actually see people walking and taking transit, and not driving around as much, because, tada! it's more convenient and faster. This kind of induced demand is also comparable to subsidies; which, like adding a lane to a highway, appear to work great at first, but quickly create a bigger problem than you started with, because you still have the same issues you had BEFORE subsidies, but now you also deal with the recurring expenditure of continuing the subsidy (because removing it will be very costly politically).
This one hit home cause I was buying property on that same corridor on I45. I backed our because of the 45 expansion and rumors of how the government was planning to use emanate domain to acquire propterty near downtown. Yet they weren't considering doing that in the suburbs to the North.
I'm wondering in these models if benefits outside of rush hour are considered in analyses. Clearly, the extra capacity is geared for the peak period. But I grew up in the suburbs of Atlanta. We frequently would drive to go to dinner or sporting events, etc. that were downtown despite living 25 miles away because the trip basically took 25 minutes with little traffic on the wide highway. Now I live in the Virginia suburbs of DC. Even at midnight, the narrow highways that barely penetrate the city often have some level of traffic, and it makes driving for non-work reasons into the city not worth it. Instead, we stay in the suburbs. Ignoring some of the positive climate implications of what I just said, I am curious to what extent that sort of demand which would be great for DC's economy is considered during widening projects. Even services like door dash benefit downtown businesses if they can quickly get out to the suburbs.
I have trouble believing much planning is done at all. I have relatives in Iowa, a state with sharply declining population. ~Two decades ago, a new interstate dubbed the "Avenue of the Saints" connected St. Paul, MN and St. Louis, MO. This brand new freeway was built for a lot of money, but then sat nearly empty after it was opened, even years later. In contrast, I did business regularly in Austin, TX. The I-35 split decks downtown were jammed. So they built a new toll road 130, bypassing Austin. Even with higher 85 mph speed limit, few people took it. Bad (or no) planning.
Fair amount of depth while still being easy to follow. Nice video, thank you!
I do live near there. Thanks for the episode!
It would be cool to explore the cost dimension in terms of VMT or something like that for a capacity project, and contrast that with transit construction. We often get "it's too expensive to build a subway" as an excuse but what's the cost of person miles travelled on a transit project vs highway?
Nice Toronto Star article pull at the beginning!
What you're talking about are super complex analyses that are super sensitive to local conditions. But this is a Simon Eh!? (TM) suggestion, so I'm required to add it to my topic list (because it's super thought-provoking).
@Citynerd: on the basic microeconic model of road capacity supply and demand, shouldn't the supply curve be more of a straight vertical line? After all, capacity supply is essentially static, even in timeframes of multiple years.
To represent lane additions, I would keep a straight vertical supply line, with every now and straight rightward shifts, to represent the shockwise addition of lanes that we often see in reality. The supply line would look like a stair, seen from the side.
Anyone in the US who lives along Interstate 75 knows it to be true....the construction NEVER stops.
3 situations I can think of where road widening happened/happening.
1. In the city of Bangalore. It's an unplanned city, and it grew rapidly after 1990, and caused a lot of traffic issues.
My college roommate was from there, he used to say, it takes 3 hours for him to go to his city, then 3 more hours within the city to get to his home.
They widened a lot of roads and assigned them as main roads, built flyovers etc.
Now the traffic situation is significantly better.
Vehicles are always zooming past in the main roads, and only local traffic uses smaller roads. Everything really improved by road widening.
2. Chamarajanagara-mysore road. It's connecting one city with another town. The town started developing recently and had a lot of jobs, most people were from Mysore, 60kn from chamarajanagara, and the road was narrow and terrible.
People were thinking it's not worth it and wanted to leave jobs. Then last year they widened the road.
Now it increased job opportunities for the town and town is improving it's economics.
3. Mangalore Bangalore highway. 2 big cities, 300km apart. One is a coastal city and gets a lot of goods through train and ships. Other is the 3rd largest city ij India. And a job-hub.
So many trucks and people use that road.
It's at a bad terrain, very narrow, just 2 lanes.
It's the bottleneck for economy.
If they widen that road, it can improve so many things...
Can you do a video on zone pricing vs flat pricing public transit? I kinda hate zone pricing, you move outside the city for affordable housing but then you pay more for those zones… European cities love doing this crap and never mention it. Which could also be another video on congestion zones and tolls.
@CityNerd 0:50 I get what you're saying, as park and ride stations sound about as depressing as the constant parking lot lined stroads that make up so much of our shopping districts (See Grape Road in Mishawaka, IN). Being that our country is so far gone down the way of car centric/dependent infrastructure and lifestyle, wouldn't park and ride stations work as a temporary step in the right direction?
If cities declared themselves as car free, like say for example South Bend, IN where I'm from, which also has Notre Dame University (Notre Dame is also it's own city) completely inside the boundaries of the city limits. If there was constant, ample, frequent, and proper public transit everywhere in the city, that's great for all of us in South Bend.
But a city like South Bend is more than just itself, it's also made up of people who live in other nearby cities and towns who come to it to work, shop, dine, and play. Cities and towns like Mishawaka, Granger, Osceola, Elkhart, Goshen, Niles MI, and more. Just because South Bend might be moving in a more car free direction, doesn't mean these other cities are. Granger, for example, is a small town of basically nothing but horrible and expensive subdivisions (when people from Elkhart and St Joe counties talk about Granger by the way, they talk about it like the be all end all destination for living. You haven't truly made it in life if you aren't living in one of the expensive subdivisions with your big ole SUV). If people from these other cities and towns weren't allowed to drive into South Bend, but had to take some sort of public transit option, wouldn't a park and ride be a good temporary option to give those car centric cities/towns a way to still interact with and invest in the city, while also keeping their cars out of it?
Also, when they all finally see how much nicer an American city is without cars everywhere, without parking lots, and with people being people, wouldn't that encourage them to become car free as well? Potentially eliminating those park and ride stations over time would happen naturally by simple force of adding their own proper public transit that connects with South Bend, and other nearby cities/towns.
Let me know your thoughts on this.
"...I felt as if I, personally, were being given to understand that I, too, was not the sort that would have done for the chief mate of a ship like the Sephora."
: every time I see the brand, "Sephora".
Did Tulsa miss out because of population? I thought our MSA hit a million a few years ago. Our downtown won a parking crater award a few years ago. The northern end (the Arts District) has some recent infill projects that are coming along nicely, but the south end is hopeless. Tulsa Community College and the big churches own most of the area and have just massive city block sized open parking lots, all connected to one another. It’s just really bad.
I think one of the biggest issues that isn't so much induced demand is that car trips are essentially badly bottlenecked pipelines because of how American cities are designed. My trip might consist of a 6-lane highway phase of the pipeline, followed by a 2-lane urban street to my work office. Unfortunately, if things like offices aren't distributed but instead clustered in one area, then a whole cluster of people has to go to work along a similar route, and the whole trip is bottlenecked by the 2-lane urban street; no amount of widening the highway is really going to make that trip shorter. Now, this is of course a vast oversimplification, because in reality, highway traffic serves a lot of different travelers going to and from different places. But it's not uncommon to see particular choke points acting as bottlenecks for getting between desirable destinations, and that ultimately boils down to a zoning problem. If you put all the houses on the left, all the jobs on the right, and expect everyone to go to work at similar hours of the day, then yeah, of course the smaller city roadways are going to get overwhelmed, because they're not built to handle the same capacity as the 6-lane highways.
Problem is, there will always be a bottleneck somewhere. The jam will just be shifted somewhere else. And with more cars, the jam will be worse.
Good stuff. What I try to wrap my head around, but can’t about induced demand is it’s chicken or the egg. I live in DFW. People are moving here. New subdivisions are getting built further and further out in the middle of nowhere. Eventually the freeway fills up and everyone is mad, so they widen it, then it fills up elsewhere. The question is would the subdivision go in if the freeway weren’t widened? Probably. It’s a never ending cycle.
It's so hard to change a vicious cycle into a virtuous one.
Lol this video reminded me of my economics lesson today 😂… the demand curve.
I have strong environmental concerns and used to use public transit in spite of the inconvenience but most mass transits systems I have seen are poorly managed and under-utilized.
This problem needs to be solved. Oil, is a finite resource
In less than 40 years Switzerland has become no.2 in train-rides-per-capita-annum right behind Japan.
The Offer creates Demand…
I live in Houston and have followed the 45 project. I have a problem with the way the commenter phrased the project. Yes they are widening the freeway, but they aren’t actually adding travel lanes. They are widening the freeway in order to extend the HOV/Toll lanes. What this will do is actually add lanes for the park and ride buses. The city likes this. The issue the city has is that the state is demolishing hundreds of businesses and homes to do this and completely ignoring local stakeholders (ie the people who own/work at these business or live in these homes). Therefore the issue isn’t actually induced traffic (tho I think the video was great and very informative of that topic).
Also there is a second part of the project where they will redirect i45 to move along the east side of downtown, which will make traffic significantly worse during construction and considering the history of construction in this city, it won’t be done for many many many years.
The positives to the second part is that the current route for i45 along the west side of downtown has dangerously steep turns and slopes and poorly aligned exits, this is supposed to confront these issues. Also since the new route will run alongside highway 59 (i69 for the uncultured) and thus look like a 20+ lane freeway, they are building a park over part of the freeway. This would allow connection between downtown and the sliver of east downtown that will be left over after they build a freeway on top of it. Also since midtown and downtown will no longer be separated by an elevated freeway, it will open opportunity for development between the two.
So really what the project offers for traffic is good. The issue is that the project will tear through primarily poor areas, and for the foreseeable future will litter our city with congestion-generating construction.
I've also been following the I-45 project. At a minimum, once you get past 610, there's the Hardy Toll Road that almost nobody uses, so paying billions to widen a freeway just to accommodate more cheapskates that won't pay a toll hardly feels worthwhile.
There's also a strong reek of general politics here. You have one political party that runs the state. The precincts where the I-45 expansion would take place vote overwhelmingly for the opposite party. The legislative districts are all gerrymandered, so a few votes at the margin is meaningless. So, the state politicians really have no reason give a **** about them (or, at least, those with the power to actually do anything beyond cast protest votes).
By contrast, the state politicians empathize much more deeply with the rural landowners between Houston and Dallas, whose farms would be impacted by the proposed high speed rail line between the cities, even though the actual number of people in that category is far less. This is because the latter group is constituents of the party in power, while the former group only elects people that have no power.
I kinda hate living in Houston because of the ridiculous traffic. I have actually quit a job because of the commute. I am very familiar with many of the highways mentioned. Even the tollway is extremely clogged. You're sitting on a paid parking lot that occasionally moves. I have used a combination of car-bus-bike-rail with a much shorter travel time than car alone. The current transportation "solution" is a joke. Houston, and many major cities like it, needs more rail and telecommuting infrastructure. If people don't have to leave home to work, the roads can be less congested. But that congestion then transfers to the fiber and tower networks.
1. There is no such thing as 'induced demand' - it is a unicorn term. 2. We are not measuring time cost, but rather generalised cost. 3. When the generalised cost goes down, more of the service is demanded on that road. When a shoe shop reduces its prices in a sale, we don't talk about induced demand for shoes. 4. The notion that widening roads leads to increased traffic is simplistic. Often a congested road is widened or transit is provided and the reduction in generalised cost leads to increased demand for road space, if the road is not congested the supposed 'induced demand' doesn't happen. Please note, applying a user charge at this point (a toll, increased tax on petrol, a tax on car ownership) does the opposite and reduces demand. 5. VISUM - that's what I use. The best option by far.
I am curious about the actual impact of HOV lanes.
More roads! That's always the answer.
These traffic flow and demand models are so complicated and it's hilarious because the solutions that are usually presented are what common sense would usually say (like someone at the office complains about a road not being wide enough and they should just add a lane or two - the eventual solution output by the complicated model is to support that obvious proposal). More to the point, these models are so complicated and model specific small, individual changes to single streets, when the real answers are to divert to transit and make large changes to make whole bad roadways different.
They're looking the wrong way and over-complicating that wrong method.
Might sound crass, but you have to include property tax in this argument. Nobody wants to live near a freeway so the land value decreases, and if property is destroyed to expand roads/freeways that's a further loss of tax revenue.
A spin doctor could probably play into people's emotions like "we have to lay off 17 school teachers and close a library to build this new lane" or something along those lines to put the economics into perspective.
One more thing I forgot to add about I-4 there is a plan to add Bright Line Fast rail to Tampa from Orlando International Airport. This will be built along I-4 since it has the space. So rail is coming in the next several years. The question is will enough riders ride on it to cut down on I-4 congested traffic. No one is talking about this or even asking the question will it run at late night hours and will it have weekend late night runs. If your leaving Disney World and Universal Studios from a Friday and Saturday night during in peak seasons is Bright Line really the utopia solution to cut down on traffic or is kind of nutty? For all these other Ultimate I-4 projects I don't see fixing I-4 to where it won't be a freeway parking lot. This project I think is expected to go Westward to the Polk County Line and further Eastward I don't know it was while back when I read something about it.
They did open the newly constructed I-4 diverging diamond at the Championsgate interchange. Yeah like that a big help if your driving past it in either direction.
Main takeaway: it's not true, but it just leads to further, bigger development, without actually fixing the real problem, too much emphasis on car dependency/infrastructure.
I think that the best solution to traffic is to reduce commute times by working locally, instead of across town.
I guess it's a tug of war between people who want businesses located centrally, and people who people located centrally.
I also think that money is the real problem. It's the main reason why people want to work or live in cities (economic opportunity).
I don’t need a complex model to figure out, that if you public transit time is 45 mins, while you can travel the same distance by car in 15 min - no one is going to use transit!
Land use should be brought up more with induced demand. Suburban homes require more VMT compared to denser urban homes. Changing land use can help reduce congestion
"No one drives in New York, there's too much traffic"
now wait just a second
Great explanation, thanks
Here is a another factor to consider. What were the road conditions like before expansion. I live in Michigan where most of the roads are in horrible conditions leading to people seeking the smoother route. When that road is rebuilt with some be widen they become the new smoother route inducing more traffic.
How would making puplic transit free impact these models?
Better roads move businesses around, which can then fill those roads up with more traffic too. For example you improve freeway access which makes it economical for a large store to open up near the freeway, this drives traffic to the big box. Cool, we expect that. But then that store drives a few local shops out of business, now a bunch of short trips (or if your city isn't dumb, walking trips) become new longer car trips and congrats you've just converted cheap, environmentally friendly short quick trips into unpleasant expensive time consuming nightmares and your freeway has more traffic on it than it did before you started. Maybe build a train next time and rout traffic around the long way.
I think Induced Demand should always center on the 5th point. I’d like to call myself a supporter of Urbanism but the induced demand argument has never made sense to me when talking about the 5th point.
I live of the Katy Freeway, which has become the poster-child for induced demand and one thing no one has mentioned with induced demand to this video is the impact of number 5. The Katy Freeway didn’t suddenly become crowded, because existing users started going out of their way to use it. The freeway borders two massive parks, so unless you where on the edge of Katy, I-10 was basically the only route. What caused most of the traffic is the 100,000 households with a median income of roughly 100,000 USD, settled in Katy, Brookshire, Fulshear, South Cypress and Northern Richmond.
Now if this highway had never been expanded where would these 100,000 folks who are predominantly, families who can afford a house with a yard and whose jobs were located in the Energy Corridor live and work?
Now you could argue that the Energy Corridor could just have been redistributed or concentrated in existing business districts. But you still have the issue of providing 100,000 homes for these people, the majority of which wouldn’t settle for an apartment, and what the best schools available, (Katy ISD is the best large school district in Houston, and it’s also a Sports/Athlete Powerhouse).
The answer is some sort of immense gentrification combined with rapid increase in prices. Vancouvers price point as well as Canadian cities and California and the Pacific NW is directly tied to artificial and natural growth boundaries combined with NIMBY-ism.
Even if you tried to build 100,000 more units to address the issue within the city. Because school desirability is such a premium, these residents more than likely would push out existing residents in existing middle class neighborhoods into lower middle class neighborhoods who would then push the lower middle class residents into these apartments or out of the city, since these apartments will likely be too expensive for the poorest residents of the city.
The city was going to grow 1,000,000 people in 10 years, regardless of whether I-10 expanded
I’ve never heard how this fundamental issue would be solved. The Elephant in the Room with the Katy Freeway is the mega suburb that also has 1000s of businesses within it and residents who relocated somewhere inside the city.
I want
I dont know the specifics around that area but for your general question a common response would be passenger rail lines running into the city with stops outside the city that you then build neighborhoods around preferably with multifamily homes to get more density around the rail stations and corner shops in the neighborhood to limit unneeded trips into the city
Thank You!!! Thx for the Explanation!!
Have there been any well known efforts to produce ML models of traffic demand? I was wondering if there are predictive models which might have a chance of capturing the “hidden” bottlenecks
I think traffic engineers generally know where the next bottleneck is going to be, but the question doesn't get much airtime because if people actually understood, then the next project might not get built quite so quickly, and then it turns off the money spigot for agencies/consultants. There are some very unhelpful incentives in play.
Thanks that makes a lot of sense. I really enjoyed the video!
I don’t agree with your supply demand curve. If you increase supply which induces demand the demand curve must also move and therefore find a new equilibrium point (it’s impossible to know where it will be but likely as the same level of delay i.e. Katy freeway or supulveda pass).
The instant the expansion is completed the demand curve is the same and thus the congestion benefits are realized. But, over time (say a couple years) the total demand shifts up and thus the amount of delay rises.
Can you cover synchronized signal lights?
Oh, that would be fun.
Great content! Really insightful. Do you know if and what differences exist in traffic management between US and Europe?
So first, does the induced demand only focuses on a focus point or takes the domino effect into consideration?
It was mentioned as aftereffect as a "future problem". Because from that I got that first they spend huge money into building a new road, and once that extra lane is finished they are reacting to newsarticles that "your project did not fixed what you promised"...
More and more cities growing. It is clearly visible that roads that been build decades ago were not designed for a 10x larger population.
Its like if someone would invent flying cars, but cities would be "no fly zones" you can have an "infinite" highway, but you will hit the bottlenecks eventually.
Second topic:
"ortodox teaching requires to be anti park n ride"
Again, when it comes to city planning this isnt good. Because that extra lane is a LOT of money. Lets not go to "its good because it generates work". Lets stay at the efficient city planning.
The same induced demand could be used for railways. And there a different planning comes. Since while a carlane can handle 1200-2000 car per hour
a metro can handle 7-10k passanger per hour. And there an extra "lane" can be an extra car.
If we add the "Return of investment" to the calculation it will shift calculations.
And I do believe there is an overcalculation issue. The effort an individual need to put into a project to see a result.
Lets say a road designer need hundreds of hours of simulation and complex metacalculations to find a "llvl99 to a 100" which would show a 2% better optimization
when the alternative transport infratractures are still at lvl 4 and fraction of the effort have a better impact because theyre underused and underutilized
where is the link to the vid you dicuss?
gee, an approximately 3-mile freeway expansion with a major arterial blocks away with a light rail line running parallel? can't possibly imagine where this hypothetical situation might apply...
I'm sure I totally just imagined it from whole cloth
@@CityNerd actually, did you make this all today? Or just incredibly good timing with the fonsi news?
@@rancidmarshmallow4468 I'm going to pretend not to know what you're talking about. But I may or may not have ideas about the thing you're talking about in Freeway Lids 2: Electric Boogaloo
After the apocalypse I will seek you out to design the next big city
If we widen bycicle paths and more people use them, they will fill more and isnt that induced demand and a overcrowding demand for that mode of transportation? If it's true for cars, it's true for bikes. Jason makes EXCELLENT points, but sometimes he shows his bias against the car.
Sure; there's certainly an "induced demand" effect for cycle infrastructure, since many will switch from cars to bikes if decent infrastructure is available.
However, the disadvantages of high levels of car traffic are obvious; It's difficult to see a downside for high levels of cycle traffic.
If cycling gets to the point where there is insufficient capacity and people are diverting onto other modes instead, is there really a good argument against increasing capacity of cycle infrastructure? Would you rather push people towards other less efficient, more expensive and more polluting forms of transport?
@@misterflibble9799 I agree with your point of avoiding less efficient and wasting materials for building cars transporting 5 people or less. My point was Jason's bias. But, everyone has the right to their point of view even if we disagree.
"Nothing in the transport system happens in a vacuum". Is that also a Hyperloop burn?
Not really. Is Hyperloop even still a thing?
@@CityNerd Yes, with the caveat that the goalposts keep shifting for what "the thing" is.
I've heard induced demand compared to fighting obesity by buying bigger clothes, and then gaining even more weight until those larger clothes are now too tight.