If you’ve ever sat through a public meeting about a new bike lane or a bus rapid transit expansion, you’ve likely heard this before: “Why are we spending taxpayer money on this? I barely see anyone using the ones we have, and the roads are already congested all the time.”
As the argument goes, if the “demand” isn’t visible on the street today, why supply the infrastructure? But this logic misses a fundamental rule of human behavior and physics. In the world of urban planning, we often talk about the phenomenon of Induced Demand as a failure—a cautionary tale of how widening a highway only leads to more traffic and potentially longer travel times.
Today, I would like to take a look at this through the lens of the individual user. Most of the time, city transportation policy isn’t about changing current behaviour, it’s more about how we hope to influence new or future residents who need to get around. In this case, induced demand isn’t a bug; it’s the most powerful tool we have for change.
From Point A to Point B
Urban planning has been heavily impacted over the years by the illustrious and influential work of Brent Toderian. Everywhere I have looked, this analogy is attributed to him, so I’m going to give him full credit.
You can’t justify a bridge by the number of people swimming across the river.
– Brent Toderian
Imagine you want to cross a river between two populated areas. There is no bridge. You look at the water and see zero people swimming across. Would you conclude that there is “no demand” for a crossing? Of course not. The demand is latent; it’s trapped by the environment.
Every piece of new transportation infrastructure—whether it’s a third lane on a highway, a protected cycle track, or a bus that comes every 15 minutes instead of 30—is a signal to the public. It is a form of encouragement. Though some people make up their mind and never change, most people aren’t “drivers,” “cyclists,” or “transit users” as a fixed identity. They are rational and flexible and end up making transportation decisions based on the available options and the following conditions (which involve tradeoffs):
- Is it affordable?
- Is it safe?
- Is it reliable?
- Is it faster than the alternative(s)?
If the answer to any of these questions is “no,” or even “not really” based on the current options, the demand remains invisible.
The Logic of the “Next 5%”
When a city decides as a one-off to put in a new multi-use pathway or adds a dedicated bus lane, it is usually a reaction to something specific, like complaints or some failure of the system.
However, cities usually have much better plans for their transportation network than deciding moment to moment what to do next. The primary goal of high-level transportation policy isn’t actually to make the commute 30 seconds faster for the people already using existing transportation modes. The primary goal is to reach or influence the marginal user, or the next people who end up moving in or moving to a certain part of the city.
This is the person who lives five kilometers from work at a new job, and is possibly even interested in biking, but won’t because there’s a 200-meter gap on the route where they have to mix with 60km/h traffic. This is the person who would also be happy taking the bus, but only if they don’t have to worry about checking a schedule to get there on time.
Infrastructure is about lowering the “activation energy” required for that next person to switch. We aren’t building bike infrastructure for the “expert” cyclist who will ride in a blizzard; we are building to make the service “good enough” for the next 5% of the population to give it a try. Once that 5% switches, you can repeat the process over and over, until the math of the entire city begins to change.
Flipping the Script on Induced Demand
Urbanists usually hear the term induced demand in a negative context—the “if you build it, they will come” phenomenon that fills up highway lanes as fast as we can pave them.
But we can use that same human drive for efficiency in transportation to our advantage. When we “induce demand” for a car lane, we are inviting more of the most space-inefficient, expensive-to-maintain mode of travel. When we “induce demand” for a high-capacity bus line or a safe walking network, we are inviting people into modes that scale.
The efficiency for current users—shorter wait times or smoother rides—is a fantastic bonus. But the real victory is the mode shift. It’s the moment the infrastructure becomes high-quality enough that a car-trip is no longer the only rational choice for a person’s errands.
The absolute wildest—and honestly hardest to believe—part of this is that when you do this, the people who still want to drive actually have an easier time doing that. This only works because there is less car traffic when more and more people can choose to use other transportation options. It feels impossible, but when this phenomenon is studied, this is the outcome every time.
Designing for our Future Choices
If we only ever build for the people we see today, we lock our cities into a permanent present. We guarantee that the only people who can move around are the ones brave enough (on a bike) or wealthy enough (in a car) to navigate the system as it currently exists.
To build a functional, fiscally resilient city, we have to stop asking, “Who is using this now?” and start asking, “Who is currently excluded by the way this is built?” and “What other options can we give people?” Transportation infrastructure isn’t just asphalt, paint, and concrete in different combinations; it’s a set of potential future decisions and choices. If we want people to choose differently, we have to give them more and better options.
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