Autonomous vehicles are a traffic solution only alongside better city planning

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.


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.

Photos by International Transport Forum and Carlton Reid

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7 Comment(s)

Rick Rybeck

Agreed. New technologies can offer some benefits in some circumstances, but they are typically incapable of rectifying fundamental flaws in urban development patterns and processes.

Fortunately, some communities have taken steps to improve those underlying conditions by shifting their property tax off of privately-created building values and onto publicly-created land values. The lower rate on buildings makes them cheaper to construct, improve and maintain. This is good for residents and businesses alike. Surprisingly, the higher rate on land values helps keep land prices more affordable as well. As an added bonus, the higher tax on land values creates an incentive to develop high-value sites — and these tend to be infill sites near urban infrastructure amenities (like transit) and this is where we want development to occur to create more walk-, bike, and transit-friendly communities that are more sustainable environmentally and financially.

For more information, see “Funding Infrastructure to Rebuild Equitable, Green Prosperity” at .

Steve Yaffe

Automated vehicles will not affect urban planning unless a large majority of vehicles in a city are automated. Otherwise, the impact on urban space won’t be significant.

Before we jump towards a society where transportation options only include walking, transit, bikeshare, and automated ZipCars, lets stop and reflect on the down-side.
1. We have the newly highlighted danger of Jihadi John’s peeps hacking automated vehicles (not just Jeeps). Should the car ignition sequence include uploading Norton or McAfee updates?
2. The quote I just heard listening to “Think like a Freak” (Freakanomics authors) that 3% of our work force drives for a living (taxis, buses, limos, trucks …). These folks are not going to be the automated vehicle computer programmers of the future – very different skill set and work environment. What is the motivation behind taking away their livelihood?
3. Are we headed towards a cradle-grave diaper society where Because some people are too irresponsible to be trusted with car keys, the reaction should be that none of us is to be trusted with car keys? Learning to deal with risk is integral to living as an adult.

I’m as far from being a Tea Party Republican as one can get, but we both can imagine a remake of “1984” in which Winston learns to love Big Nanny.


It’s a stretch to say that we’ve failed at urban planning to support your article’s handful of points when urban planning has responded to social changes over 80+ years based on what the most powerful and occasionally public-minded individuals desired from land. The roots of professional planning in the U.S. lie in some small part in getting livestock out of dense neighborhoods and ungodly industrial incinerators away from the public market for public health reasons, i.e. separation of uses.

It’s important to think beyond ten year horizons and recognize trends, even ones that occur over decades, as trends. Dense, mixed-use, transient-oriented development is an ideal urbanists have arrived at recently and will depart from one day when it ceases to be the most effective land use pattern to meet multiple social goals like congestion relief and conservation of finite resources.


Look, if you want to fight stupid zoning laws, then fight the zoning laws. Don’t pretend we ended up with “separated uses” by accident.


I see self driving cars and buses becoming a partial solution to our traffic problems.
These cars/buses should be small and electric. They would be programmed
to interact with smartphone apps to automatically pickup people going in the same
direction thereby greatly reducing the number of cars on the road.


Automated vehicles are NOT the solution. So your car drives itself, big deal. You’re still sitting in that car, on the freeway during rush hour aren’t you? Why? Because not everybody is going to jump onboard with the automated vehicle. Some people enjoy driving and won’t give it up, some people don’t trust technology enough to entrust their lives and the lives of their families to an automated machine, and if such vehicles are a similar to taxis, busses, etc., there are a lot of people, including myself who can’t stand relying and waiting on public transportation. So it’s a terrible means of looking to improve the traffic dilemma here in the Portland/Vancouver metro area.

One solution I have is investing some money and creating a toll bridge. I know I know, unpopular opinion on that but hear me out. The toll bridge is to be a completely separate bridge than that of the Interstate and Glen Jackson bridges. The toll system would be electronic, just like in most other states so no stopping is required. The incentive to this type of toll bridge is that it gives people the option to travel between the states with minimal traffic, like an expressway. This would be a great option for those that commute daily between Oregon and Washington. It would also, obviously, lessen the amount of commuters on the other two highways. Now, some people may not want to pay this “toll subscription” and that’s fine. They can pay by sitting in traffic,their choice.

But no matter what, it’s painfully clear that SOMETHING needs to happen and it needs to happen fast. It SHOULD NOT take 2 hours to drive 20 miles in ANY DIRECTION. And residential areas SHOULD NOT be dealing with the overflow. Our current infrastructure is too outdated and cannot meet the current demands. It boggles my mind that this has continued to be an issue for SO LONG and absolutely NOTHING is being done. It seems like our local governments would rather push the issue under the rug than actually DO SOMETHING ABOUT IT. Where in the hell is my tax money going?? FIX THE DAMN TRAFFIC ISSUES. I CHALLENGE YOU GOVERNMENT OFFICIALS TO DO SOMETHING AND WE WANT TO SEE RESULTS WITHIN THE NEXT 4 YEARS.



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