Shared mobility with pooled rides is the linchpin for leveraging vehicle automation and electrification to reduce congestion and emissions and to create livable urban communities. The sharing of rides is older than horse-and-buggy travel. Recent innovations make sharing easier, more convenient, and more efficient. Innovative mobility services premised on pooling can lower travel costs, mitigate congestion, and reduce greenhouse gas emissions. They also offer travelers more mobility choices between the traditional bookends of auto ownership and public transit. While the realm of shared mobility is vast, including shared bikes, scooters, and cars, the focus of this chapter is on pooled services—placing more people in a single vehicle. Doing so unlocks huge economic, social, and environmental benefits. The motivation for pooling is simple. First and foremost is economics. Cars are among the most underused capital assets in our economy, sitting empty 95 percent of the time and carrying one individual much of the remaining time. If a car were used more than 5 percent of the time, and if that car carried two, three, or four passengers, the cost per rider would drop dramatically. The benefits go well beyond cheaper mobility. Because the car would be carrying multiple riders who might otherwise be driving, there would also be fewer vehicles on the road, less parking space required, less air pollution, and reduced energy use and greenhouse gas emissions. Given that the world has more than 1 billion cars and light trucks, the potential for major reductions in pollution and greenhouse gases is huge—in the United States and also most other countries. The transition to a future where many rides are shared is now possible. What remains to be seen is whether and under what conditions people will be willing to make the transition.