What infrastructure improvements will promote the growth of autonomous vehicles while simultaneously encouraging shared ridership?
Imagine a future in which fleets of autonomous buses and shuttles effortlessly navigate through city streets to their designated stops. Ridesharing services dispatch shared autonomous vehicles (AVs) to pick up multiple passengers traveling along similar routes. Robo-taxis drop off passengers at subway stops for the next legs of their trips. Some traditional car owners decide that they no longer need personal vehicles because shared-mobility AVs fulfill their needs. Road congestion drops because there are fewer vehicles.
Now imagine an alternative future in which everyone who once owned a traditional car instead has an AV. Many people without licenses also purchase AVs for their personal use, even though they haven’t had a car for years or never owned one. Passenger-miles traveled increase by 25 percent.1 AVs circle while waiting for their owners to finish shopping or running errands if no parking spaces are available, or else they run a variety of errands, ranging from delivering groceries to picking up dry cleaning, themselves. City streets become even more gridlocked.
Which scenario will emerge around the world? The answer will depend, in part, on whether public and private stakeholders invest in the infrastructure required to enable shared autonomous mobility (SAM). But this issue gets relatively little attention now, since companies, investors, inventors, and policy makers are rightfully focusing on issues, such as safety, related to the AVs themselves. Stakeholders will soon begin discussing AV-infrastructure requirements in more detail, however, as they undertake capital planning. Some of the decisions they make now could determine whether SAM gains traction.
To help transportation officials consider the road ahead, we have identified a potential path forward for AV infrastructure that enables SAM. It includes plans for basic structural and roadway alterations that can promote AV growth, as well as improvements specifically geared at encouraging shared mobility. Transportation leaders could think about a phased approach as they consider these improvements—first implementing some infrastructure changes during AV pilots, then making additional accommodations to suit mixed traffic (AVs and traditional cars), and finally creating infrastructure that supports a complete transition to AVs.
Autonomous-vehicle infrastructure at a crossroads
With the right infrastructure to enable shared mobility, multipassenger robo-taxis could account for 500 billion miles traveled on US roads—about 9 percent of the total—by 2030. By 2040, they could account for 50 percent of all miles traveled. In addition to less traffic congestion, vehicle emissions could plunge. With more AVs in use that make fewer errors than human drivers, transportation fatalities could decline. Real estate previously dedicated to parking could be repurposed into commercial or residential properties. These improvements, in combination, could produce economic benefits totaling $850 billion annually.
To get the enabling infrastructure ready for this future state, public officials could determine whether potential transportation improvements promote SAM—both for current AVs and later models that will be fully autonomous. If they design structures with SAM in mind now, they will not have to make costly modifications later. Other related issues to consider include road pricing, zoning, licensing, and insurance.
As the public sector considers potential infrastructure upgrades, it will be important to monitor changes in AV technology. Recently, there has been increasing debate about how much stakeholders should invest in vehicle-to-infrastructure (V2I) systems, such as sensors in roads or street signs that send signals to AVs, helping them navigate city streets. There has also been much industry debate about which V2I technology is most appropriate, with opinion divided about the competing merits of dedicated short-range communications (DSRC) and cellular vehicle-to-everything (C-V2X) systems. Although evaluating specific V2I technologies is beyond the scope of this article, it is important to note the rapid growth of the V2I ecosystem (and that’s true even though automotive OEMs are piloting AVs equipped with in-car sensors and dynamic maps that allow them to operate independently). If public-sector leaders keep these potential technology changes in mind, they will make informed decisions about infrastructure.