This report explores the impacts of autonomous (also called self-driving, driverless or robotic) vehicles, and their implications for various planning issues. It investigates how quickly self-driving vehicles are likely to develop and be deployed based on experience with previous vehicle technologies; their likely benefits and costs; and how they are likely to affect travel demands and planning decisions such as optimal road, parking and public transit supply. This analysis indicates that some benefits, such as independent mobility for affluent non-drivers, may begin in the 2020s or 2030s, but most impacts, including reduced traffic and parking congestion (and therefore infrastructure savings), independent mobility for low-income people (and therefore reduced need for public transit), increased safety, energy conservation and pollution reductions, will only be significant when autonomous vehicles become common and affordable, probably in the 2040s to 2050s, and some benefits may require prohibiting human-driven vehicles on certain roadways, which could take even longer.