Balancing the Benefits of Autonomous Vehicles

Autonomous vehicles are regularly touted as holding the potential to provide significant benefits for diverse populations. There are significant technological barriers to be overcome, but as those are solved, autonomous vehicles are expected to reduce fatalities; decrease emissions and pollutants; provide new options to mobility-challenged individuals; enable people to use their time more productively; and so much more. In this paper, we argue that these high expectations for autonomous vehicles almost certainly cannot be fully realized. More specifically, the proposed benefits divide into two high-level groups, centered around efficiency and safety improvements, and increases in people's agency and autonomy. The first group of benefits is almost always framed in terms of rates: fatality rates, traffic flow per mile, and so forth. However, we arguably care about the absolute numbers for these measures, not the rates; number of fatalities is the key metric, not fatality rate per vehicle mile traveled. Hence, these potential benefits will be reduced, perhaps to non-existence, if autonomous vehicles lead to increases in vehicular usage. But that is exactly the result that we should expect if the second group of benefits is realized: if people's agency and autonomy is increased, then they will use vehicles more. There is an inevitable tension between the benefits that are proposed for autonomous vehicles, such that we cannot fully have all of them at once. We close by pointing towards other types of AI technologies where we should expect to find similar types of necessary and inevitable tradeoffs between classes of benefits.