I don’t disagree with the conclusions this study is reaching, but I think allowing the use of runs with an empty vehicle really messed with the data. We will eventually reach that kind of tech, but if we’re trying to experiment and model near future societal change, that was an irresponsible variable to throw in that feels like it was just there to shore up the numbers.Of course if my self driving car could drive empty I would have it do pick up-drop off trips to save on parking (unless it was like an hour+ drive). Of course if my car could pump it’s own gas and pick up it’s own groceries (I thought those were some pretty ridiculous things to allow, that assumes that part of the “self-driving” infrastructure is technology or services that allow those kinds of things) I’m going to have it do that. Those definitely would increase VMT, but traffic? If my car can drive itself I can set it to pick up groceries at 2 AM when the grocer opens, or set a recurring gas refill at 1 AM. If people are able to stagger trips like that to times when they don’t need to be available, the average traffic amount per hour would increase, but I think you would smooth out high traffic times.
The biggest weakness of this study (which I won’t fault it for, you can’t model everything) is neglecting to consider all the other societal changes that are also happening right now. Yeah, self driving cards would allow everyone to move to the boonies and drive a thousand miles a day, if somehow everyone could afford a damn house. Even with self driving car tech I don’t see why the gigantic population of people in cities need a car, even discounting public transit traveling by bike/on foot is more efficient and faster than a car in the city. The increase in telecommuting and work from home culture is also going to reduce a significant amount of VMT required for people to make a living.
Referencing this study as a counter to the BS claims people in self-driving tech make is useful, but I wouldn’t rely on it as data for policy or infrastructure