Perspectives

Autonomous Vehicles Are a Traffic Solution Only Alongside Better City Planning

The reason we have such congestion is not because we have low-tech vehicles that require excessive braking space -- it’s because we have failed at urban planning.

by Chris Plano, Mobility Lab / July 28, 2015

Autonomous vehicles – or self driving cars – are promoted as a solution to congestion because researcher Todd Litman and many others expect that sensors will allow cars to travel closer together.

But it has been proved time and time again that road-widening leads to induced demand, which means that additional lanes get just as congested as they were before within a short time. Would induced demand also arise with the wide adoption of autonomous vehicles, which would create all that new extra road space?

It’s easy to see that people would then move in droves from standard vehicles and transit, quickly filling up additional road capacity made possible by autonomous vehicles. Why wouldn’t they? When your commute can now be used to read, work, or nap like it was on transit, but can also be door-to-door as it is when you drove your car?

At that point, we are back to square one discussing road widening, congestion tolling, and HOV lanes just as we are today. After all, an autonomous car takes up as much physical space as a car with a human at the wheel. And this image clearly shows the inefficiency involved in traveling by car.

Image by Carlton Reid

Our society often fixates on simple, technological solutions to problems rather than more holistic approaches. Take the California water shortage as an example. Cities such as San Diego have chosen to build desalination plants to turn seawater into drinking water. The Carlsbad plant will cost $1 billion to build, and plenty more to operate every year.

Rather than convince ourselves yet again that a seemingly simple technological solution is the key, let’s take a step back. The reason we have such congestion is not because we have low-tech vehicles that require excessive braking space. Rather, it’s because we have failed at urban planning.

If we had created mixed-use areas with a healthy blend of shopping, restaurants, employment, and housing, we could accomplish errands, go out to eat with friends, and possibly even work in our own neighborhoods. If we had created places that were transit-oriented, we could easily get to other places for the things we can’t do in our own neighborhoods, or get bored of doing there. And if we had created walkable, human-scale neighborhoods, we would feel more safe moving around by walking and biking.

Instead, we have separated uses that have created car-oriented places and unwalkable, car-scale neighborhoods. And that kind of built environment has produced congestion.

But we must treat the cause of congestion, and not the symptom. By making cars a bit more efficient at moving people through a limited amount of lane space, we treat the symptom of traffic jams. However, the cause here is a poorly-planned built environment that forces dependence on vehicles, and often those vehicles end up sitting in traffic. By remaking the world around us to support better ways of living and moving, we address the cause and give people the freedom to move in ways that don’t inevitably lead to wasted time in traffic.

We should focus our energies on making our cities walkable, human-scale, transit-oriented places. Without this shift, we will likely be addressing the same issue of congestion in the future.

Autonomous vehicles have their benefits, such as being a possible boon for transit agencies’ low-ridership bus routes, but we cannot expect a technology to solve a design problem.

This story was originally published by Mobility Lab. Republished with permission.