The number of self-driving vehicles is expected to increase, following the U.S. Department of Transportation's December 2018 decision to ease federal oversight of autonomous vehicles and Congressional plans to reintroduce legislation that could add as many as 100,000 vehicles with significant autonomous functionality to the road by 2022.

In the meantime, hundreds of self-driving vehicles are already motoring around, unnoticed for the most part. To date, 29 states have enacted legislation related to the use of autonomous vehicles on state roads, with another dozen states lining up to do the same. As the National Highway Traffic Safety Administration (NHTSA) recently predicted, "Fully automated cars and trucks that drive us, instead of us driving them, are a vision that seems on the verge of becoming a reality."