How to make roads safer for AVs

No matter how much developers test AVs, the world will still present unforeseen circumstances for vehicles to navigate. Researchers and policymakers want to mitigate these risks by making roadways more accommodating of mistakes.

The big picture: Road safety policy can help offset these challenges and better plan for AV deployment, particularly the Safe System approach that originated as part of Sweden's 1997 Vision Zero initiative. Countries that have implemented similar policies have seen declines in traffic fatalities, and others could follow their models.

Background: Real-world road accidents from 2018 illustrate the surprising variety of "unknown unknowns" vehicles encounter: a 20-fatality limo crash in New York caused by poor road design and vehicle maintenance; a speeding car launched off a raised median into a second-story office in California; and an Oregon roadway made slippery by a truck spill of 7,500 pounds of slime eels.

Details: The Safe System approach focuses on three intersecting tenets: Road safety is a shared responsibility; transportation initiatives are based on both experience and anticipated problems; and AV systems, like human drivers, are fallible.

How it works: Roadways and vehicle design can be modified to be more forgiving of mistakes and AV system shortcomings.

• Enhanced lane divisions to prevent head-on collisions
• Traffic-calming devices like roundabouts
• Rumble strips to keep drivers in their lanes
• Lower speed limits and alerts when those limits are exceeded
• Structures to minimize lethality of crashes inside the vehicle (strengthened roof and chassis) and outside (safer designs for guardrails)

The bottom line: A roadway designed to accommodate human error, whether the human is behind a steering wheel or behind a computer, could better protect motorists, and the AVs that may soon populate it.

Laura Fraade-Blanar is an adjunct researcher at the nonprofit, nonpartisan RAND Corporation.