The two cultures of robocars


I have many more comments pending on my observations from the recent AUVSI/TRB Automated Vehicles Symposium, but for today I would like to put forward an observation I made about two broad schools of thought on the path of the technology and the timeline for adoption. I will call these the aggressive and conservative schools. The aggressive school is represented by Google, Induct (and its successors) and many academic teams, the conservative school involves car companies, most urban planners and various others.

The conservative (automotive) view sees this technology as a set of wheels that has a computer.

The aggressive (digital) school sees this as a computer that has a set of wheels.

The conservative view sees this as an automotive technology, and most of them are very used to thinking about automotive technology. For the aggressive school, where I belong, this is a computer technology, and will be developed -- and change the world -- at the much faster pace that computer technologies do.

Neither school is probably entirely right, of course. It won't go as gung-ho as a smartphone, suddenly in every pocket within a few years of release, being discarded when just 2 years old even though it still performs exactly as designed. Nor will it advance at the speed of automotive technology, a world where electric cars are finally getting some traction a century after being introduced.

The conservative school embraces the 4 NHTSA Levels or 5 SAE levels of technology, and expects these levels to be a path of progress. Car companies are starting to sell "level 2" and working on "level 3" and declaring level 4 or 5 to be far in the future. Google is going directly to SAE level 4.

The two cultures do agree that the curve of deployment is not nearly-instant like a smartphone. It will take some time until robocars are a significant fraction of the cars on the road. What they disagree on is how quickly that has a big effect on society. In sessions I attended, the feeling that the early 2020s would see only a modest fraction of cars being self-driving meant to the conservatives that they would not have that much effect on the world.

In one session, it was asked how many people had cars with automatic cruise control (ACC.) Very few hands went up, and this is no surprise -- the uptake of ACC is quite low, and almost all of it is part of a "technology package" on the cars that offer it. This led people to believe that if ACC, now over a decade old, could barely get deployed, we should not expect rapid deployment of more complete self-driving. And this may indeed be a warning for those selling super-cruise style products which combine ACC and lanekeeping under driver supervision, which is the level 2 most car companies are working on.

To counter this, I asked a room how many had ridden in Uber or its competitors. Almost every hand went up this time -- again no surprise. In spite of the fact that Uber's cars represent an insignificant fraction of the deployed car fleet. In the aggressive view, robocars are more a service than a product, and as we can see, a robocar-like service can start affecting everybody with very low deployment and only a limited service area.

This dichotomy is somewhat reflected in the difference between SAE's Level 4 and NHTSA's. SAE Level 4 means full driving (including unmanned) but in a limited service area or under other limited parameters. This is what Google has said they will make, this is what you see planned for services in campuses and retirement communities. This is where it begins, and grows one region at a time. NHTSA's levels falsely convey the idea that you slowly move to fully automated mode and immediately do it over a wide service area. Real cars will vary as to what level of supervision they need (the levels) over different times, streets and speeds, existing at all the levels at different times.

Follow the conservative model and you can say that society will not see much change until 2030 -- some even talk about 2040. I believe that is an error.

Another correlated difference of opinion lies around infrastructure. Those in the aggressive computer-based camp wish to avoid the need to change the physical infrastructure. Instead of making the roads smart, make the individual cars smart. The more automotive camp has also often spoken of physical changes as being more important, and also believes there is strong value in putting digital "vehicle to vehicle" radios in even non-robocars. The computer camp is much more fond of "virtual infrastructure" like the detailed ultra-maps used by Google and many other projects.

It would be unfair to claim that the two schools are fully stratified. There are researchers who bridge the camps. There are people who see both sides very well. There are "computer" folks working at car companies, and car industry folks on the aggressive teams.

The two approaches will also clash when it comes to deciding how to measure the safety of the products and how they should be regulated, which will be a much larger battle. More on that later.


Hi Brad,

Love your blog!

I have heard much about the fuel efficiency gains from vehicle automation - both in terms of driving closer together (reducing air drag), and in terms of built-in eco-driving (anticipatory braking, no excessive throttle movement, etc.). I was just curious if you are aware of any real-world fuel efficiency improvements on current and past AV prototypes. I have heard values of emissions reductions from 5-80%, and I have a hard time imagining the Google Prius' or Lexus' getting something quite as significant as that higher range.

Any thoughts?



Savings from doing convoys are real but modest, 5% to 20% in various experiments, and there have been a variety of experiments. Not enough to be the sole reason for this, but worth doing if you can do it -- but only later since shorter headways have a safety consequence. (A commercial company is planning to build this for trucks, but the following truck will still have a driver.)

The big energy savings come when you have mobility on demand service, cars that can deliver themselves to you. This makes it very reasonable to delivery people small, efficient cars for their short, solo, urban trips, which are 80% of all trips. Today, everybody drives in 5 passenger sedans, pick-up trucks and SUVs because we all buy multi-purpose cars to meet all our needs. But only a small fraction of our trips actually need them.

The savings from that are huge -- A small, electric single person city car can use less than 15% of the energy of today's typical sedan.

I see now, this makes sense.

Much appreciated - Thank you!

The Sartre platooning project demonstrated gains of up to 16% for trucks at a 6 metre gap, which I think is quite substantial considering the amount of fuel they use over the year.

It's worth doing, though it faces many problems -- finding the other truck to platoon with, and the thrown stones which damage the rear vehicles. However, for safety, it's not something I would do early, though Peloton is trying to do it.

There are other fuel savings from more regular driving, and also from knowing the timing of lights and not wasting fuel rushing up to stops, though those savings are also mostly attained with regen braking.

Nothing comes close to the savings from using more efficient vehicles.

Fuel efficiency is obviously not the only consideration here.
Estimates I've seen for the increase in road capacity allowed by robocars vary from as little as 30% to 500%.
The latter including the effects of increased load factor when robocars are combined with Transport As A Service.
I don't know the cost of roading per km to compare it with fuel costs, but I will hazard a guess that the potential savings outweigh those achieved by reduced fuel usage attributed to platooning.

You do get a capacity increase if you decrease the headway (following distance.) Platooning is not required for that, it's just one way to get it, and to get it without freaking out the car you're following.

However, fuel savings are realized directly by the owner of the vehicle which saves fuel. Road capacity increases are harder to sell because the people paying for the tech gain minimally. That means it doesn't happen on its own, rather it just slowly gets better as more people get vehicles able to follow closely for other reasons.

Because of the freak-out factor, you may see platoons -- though not for some time as they present a safety risk and you never start with a safety risk -- but it's a pretty hard problem to figure how how to form them, or find others willing to form them.

Brad, great post as always. I would not go around calling it the "aggressive" view/strategy. That just sounds scary and the "progressive" view suffers mainly from people's fears. In my mind the dichotomy was always car companies vs. transportation companies. (Similar to oil companies vs. energy companies.) By being car companies, the conservative strategy limits themselves to cars only. Transportation companies can do things like Uber. Even Google, with their maps and navigation is a transportation company already and they are not limited in their creative thinking.

It is reasonably obvious that requiring infrastructure changes is probably a lose lose proposition. First different jurisdictions will (or won't) try different versions which will diffuse adoption and success to companies requiring those changes.

Second, companies that simply don't require changes will be able to compete anywhere. Both in jurisdictions that are late to the party (no changes) and in places that made changes (by simply ignoring them like normal human driven cars do.)

Overall the companies that don't need changes will have far more places to sell their product.

Great synopsis. Another dichotomy I've noticed is that the more radical the tech, the more limiting your area you can deploy. In other words, if you want a car that can drive in any situation, it will be incremental, OEM tech on existing cars. If you want a totally new vehicle architecture like Google or CityMobile2, you need to aggressively limit where it can go (eg, 25 mph, highly regulated campus environment with fixed routes). Another issue is OEMs percentages are based on car sales but a shared vehicle can serve 20-90 people per vehicle depending on the model so even a small number of vehicles could have significant impact. I think there are pros and cons to both approaches & each has a place.

That's just because they're nibbling at the problem from opposite ends. The bottom-up (conservative) approach increments on existing cars and adds in sensors, actuators, and intelligence bit by bit. The top-down (aggressive) approach starts will full automation and specifies a region of operation that can be supported by current technologies. One day the two approaches will meet in the middle in the sense that they can operate on the same roads under the same operating conditions. The difference will be that one kind of car will still have controls, while the other will not.

I am having a guess that the incremental bottom up approach is going to run into too many problems. Whilst computers can assist humans in driving, actually being in control is not something that can be shared at the same time. There may be a good case for computer control over part of the journey, say the highway driving, but not the street driving. But even here the swapping of control has its own problems.
I think Google are right in trying to leapfrog past this zone of shared control. The major benefits of driverless cars happen when the cars are actually able to make journeys without drivers. This then allows for car sharing and removes the need for parking. The result could be a game changing reduction in transport costs.

Perhaps the most important statement is this one: "The big energy savings come when you have mobility on demand service, cars that can deliver themselves to you. This makes it very reasonable to delivery people small, efficient cars for their short, solo, urban trips, which are 80% of all trips. Today, everybody drives in 5 passenger sedans, pick-up trucks and SUVs because we all buy multi-purpose cars to meet all our needs. But only a small fraction of our trips actually need them.
The savings from that are huge — A small, electric single person city car can use less than 15% of the energy of today’s typical sedan."
Autonomous taxi shuttles (aTaxis) seem to have huge potentail in improving service and lowering costs per ride. Who can help Greenville SC demo these type vehicles in the next few months?

The issue with pointing to low uptake of adaptive cruise control as indicating consumer distrust is that, as you point out, ACC is still considered a luxury upgrade feature.

It's sort of like anti-lock brakes or rear-view cameras--or air conditioning, for that matter. It used to be that these things were top-of-the-line full-trim features, and their deployment was very limited. Nowadays you get antilock brakes and A/C without even asking, and rear-view cameras are increasingly common at standard trim levels. And consumers are seldom offered the ability to pick and choose upgrades; someone might want ACC but not want to have to buy the vinyl seats, better speakers, fancy wheels, LED headlights, etcetera that come with the package.

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