THE SYSTEM OF STREETS AND VEHICLES AS A MORAL MACHINE
Our network of roads and the rules that govern them enables the public’s freedom of mobility. This network is used by people and vehicles every day. Its infrastructure, together with the patterns and movements along it, can be viewed from above as an autonomous system. It is a system containing individual mobility choices that also form larger patterns when observed at scale.
The topological and legal infrastructure of our roads are the foundation for computer routing algorithms and human decisions about how to move from here to there. The route for a car may be determined by physical factors, such as which roads are shortest and how the roads are connected, as well as governed factors, such as which roads are one-way or have stop signs or multiple lanes.
The shortest and most efficient route is often chosen for cars. Safety is a larger consideration for those on bicycles or foot, and their safe choices are limited. Few US roads have dedicated lanes for bicycles, but bicyclists may be better off limiting their routes to them. Likewise, pedestrian routes may be limited to where sidewalks and crosswalks are present. As such, the network of streets and its rules in which the public moves is car-centric, and those outside private vehicles often must take a backseat.
Our current system of streets embeds a prioritization for cars in both structure and governance that is inequitable. Structural factors include how bike lanes and crosswalks are limited features of streets; the streets are otherwise the domain of vehicles. There are also governed factors, such as right-of-way laws which determine when a vehicle is required to yield. Bicycles are considered “vehicles” by law, so they are subject to the same rules as car drivers; although bicycles are more vulnerable than cars, they are not generally granted right of way. US federal and state right-of-way laws require cars to yield to other cars that arrive first to intersections. They only require yielding to pedestrians who are already in crosswalks, but not necessarily to pedestrians waiting to cross (*5). These requirements encode an underlying preference for cars. Crosswalks are intersections for pedestrians, yet pedestrians must wait at intersections while other vehicles are given preference. Even when bicyclists and pedestrians do have legal right of way, they still have a practical need to yield to vehicles; vehicles are more powerful. In the case of a collision, a car’s driver will likely be safe while a bicyclist or pedestrian will suffer bodily harm. Whether they had legal right of way will matter little compared to the harm sustained by them.
The US public relies on the system of streets for mobility, but the current system that prioritizes privately operated cars is not serving the public equitably. A system that prioritizes and incentivizes shared transit, biking, and walking can be a more moral one with social impact along 3 main avenues:
- Safety: A system that prioritizes the safety of higher occupancy vehicles and the most vulnerable on the streets (pedestrians and bikers) will see fewer fatalities on the roads.
- Sustainability: When people transition from personal vehicles to shared transit, bikes, or walking, there is less pollution from cars.
- Equity: More shared transit enables those who otherwise have limited access to personal automobiles or mobility options.
Although there are public shared vehicles, namely buses, they are often under-resourced. Increasingly, private car sharing services, such as Uber and Lyft, have filled a void. The continued success and expansion of these companies is a testament to the public’s growing appetite for shared vehicles.
The increasing use of shared vehicles, whether supplied by public transit agencies, or private car sharing services, can be furthered by the design of mechanisms that prioritize higher occupancy vehicles on the road. These mechanisms can be implemented within AV driving software along with other rules that benefit bicyclists and pedestrians. The result will be that as new AVs drive into our future streets, the new priorities embedded in their driving software will as well.
As the public begins thinking about vehicles as shared goods, their expectations regarding how vehicles should be regulated and the rules that guide them will change. A public that views vehicles as shared goods will be more likely to favor utilitarian rules and regulations for the vehicles. At the same time, rules and regulations for AVs can act as mechanisms to shift how vehicles are used and help facilitate a public change in perception of vehicles as private commodities to shared goods. For example, rules that cause a vehicle to yield to higher occupancy vehicles will make shared transit more efficient, safer, and thus more appealing. In this way, changes in public perception of vehicles, and changes to rules to match the public’s changing expectations for vehicles, can be interrelated and cyclical.
Described below is a two-part design to guide such a cycle towards the more moral system of streets envisioned for the future:
- An update to laws for the streets and vehicle regulations in order to prioritize high occupancy vehicles, bicyclists, and pedestrians. These rules will guide the design of algorithms that drive AVs.
- A requirement that all AV driving algorithms be open source. This will enforce a transparent implementation of the rules and regulations.