On the other hand, if I were creating a fleet of self-driving taxis, and I could choose between 50mpg cars or 20mpg trucks/SUVs, I'd use 90% the former.

People buying personal cars at the moment tend to choose the latter: https://www.edmunds.com/most-popular-cars/

Better even... Delivery "cars" could be roughly the size of smart cars, with just a relatively big storage cabin.

Most of the self driving cars should be fleet, so I doubt any of these specifically will occur. It will be more like having cheap reliable taxis around, and anyone who has lived in a cheaper country (like China) might understand that.

Coupled with electrification going on at the same time (many countries and states have set 2030 or 2035 deadlines), the CO2 impact won't be as bad, although we should still focus on public mass transit.

There are a lot of countervailing trends, some directly the opposite of what is predicted here: Delivery, not pickup, for example. Right-sized shared vehicles with surge capacity instead of "orbiting" private cars. Smaller-lighter vehicles as the need for crashworthy vehicles declines. More use of bicycles as roads become safer for cyclists.

Overall, automated road vehicles are a huge boon.

> * cars doing the minimum to stay 'in traffic' to avoid paying high fees for parking

> * far more miles per car because the biggest limiting factor (the presence of a driver) will wall away

> * huge CO2 impact (negative) from all these extra miles

These are all very important. Most cars on the road are single occupancy. Once we can have zero occupancy the problem will only get worse.

Wouldn't it be the other way, through fleet network effects?

For example, your fleet of low- or zero-emission vehicles would greatly offset the average vehicles that people would have been using instead.

Also, zero occupancy vehicles never have to drive around looking for parking near their destination. They are immediately reusable or could go to an out-of-the-way pool.

> kids sent to school with the car to circle back and pick up the parents afterwards

Isn't this backwards? Why should kids have to go earlier than parents if the parents don't need to drop them off before work?

> huge CO2 impact (negative) from all these extra miles

Won't most automated vehicles be electric?

> Isn't this backwards? Why should kids have to go earlier than parents if the parents don't need to drop them off before work?

Because in most places school starts before work starts, this has always been the case, even in places where people don't have cars, and not everybody has a car in places where most people do.

> Won't most automated vehicles be electric?

Yes, but that doesn't automatically mean all that power is made with renewables.

>Yes, but that doesn't automatically mean all that power is made with renewables.

Electric vehicles are consistently more carbon efficient than individual combustion engines, except for specific outlier instances in developing countries which are 100% dirty coal power grids.

This means a fleet of electric vehicles will have less of a carbon impact per mile than the average human driven vehicle.

This is true in the case where you compare a fleet of electric vehicles with the same size fleet of combustion based vehicles.

But that's an entirely different subject. We are simply looking at the effect on the total number of miles driven here, which will absolutely explode once driverless vehicles are a reality. And those KWh will have to come from somewhere and they will have a carbon footprint even when they are entirely made with renewables.

The solution to this is to drive substantially less not to drive more with cleaner vehicles.

There is no reason to believe that driverless cars will be driven more than regular vehicles, and even if they were, you'd be able to regulate fleet pricing to stem overusage.

There is still no comparison between electric vehicles and combustion vehicles in terms of carbon footprint.

Also:

- Mass transit is full of big heavy vehicles running mostly empty on off-peak hours. It's more efficient only at rush hour. I'd expect net efficiency over the full usage is worse, compared to electric cars.

- As they start making custom robocar hardware, it'll become a mix probably including smaller lighter single-occupancy cars.

- Mass transit ought to become much more useful and attractive given on-demand robocar rides to and from your station.

- (Added:) Congestion pricing becomes more doable for cars that are already networked for other reasons. Congestion pricing is the obvious approach to really solving congestion.

> Mass transit is full of big heavy vehicles running mostly empty on off-peak hours. It's more efficient only at rush hour. I'd expect net efficiency over the full usage is worse, compared to electric cars.

That is really only true in the states right? In other countries with decent mass transit systems, it seems like they are really full during rush hour but only mostly full at other times, utilization is very good. American systems seem to be dysfunctional...probably because cars are more convenient for off peak travel. I can see how door-to-door automated vans or even taxis could fill in off peak travel here, while the big vehicles serve mostly peak demand (in the states, elsewhere it isn't as needed).

Yeah, I looked up this overview https://www.templetons.com/brad/transit-myth.html and it agrees there's a difference from European/Asian systems.

> cars doing the minimum to stay 'in traffic' to avoid paying high fees for parking

Parking will get cheaper, if anything:

- Electric AVs can park themselves 5x further away with no UX downside and minimal energy cost.

- Nobody needs to use the doors while parked, and AVs can cooperatively rearrange themselves to allow ingress or egress, meaning they can park with almost no clearance in all directions.

- Parking garages can be designed with the assumption that vehicles are driven with perfect precision, allowing wasted aisle space to be significantly reduced.

I think the cars picking up things/people without drivers could be the worst part. Imagine being driven in a taxi, and about half of the vehicles around you have nobody in them. I suppose it's not inherently wasteful since you never really needed to be in the car to go pick something up. However, if the price of delivering something by car decreases a lot, the volume of deliveries will increase a lot too.

A lot of places have looked at taxation by miles travelled, and that would address a lot of those. For places with high fuel taxes today this is particularly attractive with the transition towards electric cars.

> * kids sent to school with the car to circle back and pick up the parents afterwards

Only if the parents are WFH and going to lunch. School starts too early already.

Sending your kid by themselves in a taxi isn't an uncommon thing in China. I can't imagine that changing much with self driving cars, but I understand the American perspective isn't already used to such things.