In the late 1990s the Katy Freeway in Houston faced a problem. It was severely congested, and congestion lasted for hours each day. Everything is bigger in Texas, so when TxDOT chose to try and solve the congestion they did so in a big way, expanding the freeway to six general purpose lanes in each direction and two HOV lanes in the median as well as multiple frontage lanes on each side. At its widest point there are 26 lanes of roadway. This mother of all traffic projects was supposed to end congestion forever at the cost of 2.8 billion dollars.
There was a significant decrease in congestion immediately after the project. But just several years later speeds had again slowed and congestion had increased once more. The project had not provided the lasting congestion relief that its proponents had had hoped for. For hours each day cars are creeping through the city weighed down by all that traffic. What happened?
The answer is induced demand.
Induced demand is the term for the increase in driving that occurs when a transportation project expands road capacity, making driving easier, faster, or more convenient. The change in environment caused by the project leads people to change when, to where and how often they use cars. The presence of a new vehicle corridor causes changes in development, investment and land use over time.
In the case of the Katy Freeway, a few things are thought to have happened:
1) Route shifting: people who used other routes to get where they were going started using the freeway once it was expanded.
2) Time shifting: people who deferred trips to different times of day (i.e to avoid rush hour) could now use the freeway when they desired
3) Mode shifting: people who walked, biked, carpooled, used transit or otherwise avoided driving, started driving since the freeway degraded their previous modes and driving became easier, faster and more convenient.
4) Trip generation: with expanded capacity, people who avoided making a trip due to the time it required started making those trips.
5) Land use changes: New housing developments got built further out that depended on the freeway, and businesses invested in land next to the freeway to become accessible, driving more use.
Induced demand sometimes gets portrayed as a quasi magical effect: that bike advocates and urbanists think new roads magically make people drive more. Rather, it is a paradoxical unintended outcome of many individuals making rational decisions to take advantage of expanded infrastructure as it becomes available.
It’s important to point out that none of these effects were necessarily unintended (with the possible exception of mode shifting). The intent was clearly to ensure that Houstonians could easily travel when they wanted, where they wanted, how they wanted. But the point is that time and travel are subject to the same economic considerations other resources are. TxDOT had made travel along the Katy freeway have a low time-cost. Houstonians found uses for that low cost travel resource, until demand drove up the time-price. Even a project as large as this one led to only temporary improvements in congestion. When the cost of car travel becomes cheap (both in time and money), people use more of it.
In Bend, thankfully, we are not currently planning on expanding any of our roadways to a similar degree as done by TxDOT. However, we have undertaken projects to expand roadway capacity. The logic of induced demand suggests that the benefits from these projects will be short lived. The city is currently planning to expand the roundabouts at Reed Market and Bond and Reed Market and 15th into multi-lane turbo roundabouts. They are planning to convert a signalized intersection at 8th and Olney into a partial multi lane roundabout. This is being done in the name of congestion relief and concern that we will need the increased car traffic capacity in the future. These projects will likely lead to some relief of congestion initially, but it is unlikely to be sustained over time. How many people who choose to use other routes to bypass these congested areas currently will shift their driving patterns once the corridor becomes uncongested (route shifting)? How many people who currently avoid traveling through these intersections at peak travel hours will choose to drive at those times once more (time shifting)? Will people who currently walk or bike through these intersections feel it is no longer safe to do so and choose to drive instead? It seems unlikely that these projects will lead to sustained decreases in travel times as Bend continues to grow, but they will leave us with infrastructure that is less safe and that are barriers to other ways of getting around.
Similar considerations can be applied to the recent completion of the US 97 Bend Parkway plan. The new roadway has made traveling north from Bend to Sisters and Redmond much easier by car, avoiding the lights and congestion from the businesses in Cascade Village. But we are also seeing increased development along that corridor (effect 5 – land use changes). Supporting this development is part of the rationale for the original project. One only has to stand in the sea of cars around the new Costco to see how some of the changes in land use along this corridor are changing traffic patterns. That illustrates an important feature of induced demand: transportation projects don’t just serve a static set of uses—they can help create the conditions for additional development. I would expect that as our city continues to grow to the north, and new businesses attract residents to their offerings, that the increase in traffic will outpace the capacity, leading once more to the very congestion that is now relieved.
Roadway expansion projects can encourage people who previously tried to use other modes (walking, biking, public transit) to drive instead, and thus bake in car dependency. With each lane, a road gets significantly more difficult for people walking and biking to cross. Drivers also tend to go faster, increasing consequences when there is a collision. There is a huge difference between walking on the sidewalk or riding in the bike lane on 3rd street compared to riding on Franklin (even before the improvements), Olney or Wilson. The perception that biking or walking is unsafe is one of the most common concerns that we hear when advocating for people getting around by foot or bike. Larger roads and intersections will likely only make this problem worse – indeed the new businesses north of town near Costco on an island surrounded by a sea of pavement. Accessing these businesses by foot or bike even if you wanted to is very difficult.
Further, expanding roadways contributes to sprawl. With larger roadways, longer commutes can become more tolerable, and land that could be housing is taken up by roads, pavement and attendant infrastructure. While sprawl is somewhat slowed in Oregon due to our urban growth boundaries, many people commute from LaPine and Redmond to jobs in Bend. Devoting more land to car infrastructure itself makes other modes of travel more difficult to make work on a community level. This sort of development further entrenches car dependency and makes it ever harder for people to choose other options than driving.
At Bend Bikes, we believe the solution to congestion is to give people more choices: more ways to travel, and more places where they can meet their needs without having to drive. Prioritizing safety, walkability, bikeability and public transit is thus paramount to a long term and sustainable relief of congestion. Cars will be with us for the foreseeable future, and we all have trips that need them – but many of us have a lot of trips that could be done with another mode – either by foot, by bus or by bike. Making using these other modes more attractive can lead to more sustainable reductions in car volumes. Congestion increases rapidly as roads approach capacity, so even modest reductions in the number of cars traveling during peak periods can produce meaningful improvements in traffic flow. By working with our fellow advocacy organizations we can also encourage changes in zoning that allow people to meet their needs in their own neighborhoods where things are just a few minutes away by foot or pedal. We think this is a more sustainable and fiscally responsible approach that preserves the vibrancy and livability of our city.
If you agree and are excited to help Bend support a diversity of travel modes, maintaining the livability and character of our wonderful high desert community, send us a message at [email protected] and we can have a conversation about how you would like to get involved.