Shared mobility includes a variety of modes that move away from the dominance of privately_x0002_owned, single occupancy passenger vehicles. The broad concept can be split between: i) the sharing of vehicles, including car-sharing, bike-sharing, and scooter-sharing; and ii) the sharing of rides, including ride-hailing and car-pooling. Numerous studies argue that in addition to the enormous transitions in fuels and efficiency needed to meet net zero CO2 goals, “behavior changes” will also be needed. In transportation, this usually refers to reductions in the rates of vehicle ownership and vehicle usage. Ride-hailing Ride-hailing is defined as an app-based platform that allows users to hail a ride from a professional driver. Uber and Lyft are the most well-known service providers on most countries. It is important to distinguish between: i) individual-use ride-hailing, that is, taking a trip alone or with friends/acquaintances; and ii) pooled ride-hailing where a trip is shared among two or more strangers, aside from the driver. These trips generally require multiple pick-up and drop-off points and have more potential to lead to GHG reduction. The environmental impacts of ride-hailing are generally unclear, as it is difficult to identify the different orders of impacts. Car-sharing Car-sharing involves a traveler paying an hourly and/or mileage-based rate to pick up a vehicle, use it, and return it somewhere. Car-share programs vary in a number of ways. In particular, parking can be station-based or free-floating, and trip structure can be one_x0002_way or two-way. Peer-to-peer (P2P) car-sharing is an emerging form that allows individuals to rent out their personal vehicles. The net societal impacts of car-sharing programs are uncertain, though it is often considered as a pathway to reduce vehicle ownership. Shared micro-mobility Micro-mobility follows similar principles to car-sharing, but includes the sharing of bikes, e-bikes and e-scooters. There is the added variation that some such programs are “dockless”, with no particular parking or storage space. Shared e-scooters have over-taken shared dockless bikes in Europe, Central Asia and North America, though shared bikes are more popular in East Asia and Pacific countries. There has also been a recent increase in the use of swappable batteries, which allows operators to quickly replace depleted e-scooters and e-bikes with fully charged batteries. Mobility-as-a-Service The concept of Mobility-as-a-Service (MaaS) aims to advance the potential complementarity of public transit and shared mobility. The hope is to increase the usage of both modes, and ultimately to reduce private vehicle ownership and usage. MaaS can be defined as defined as follows: with a single payment and streamlined user experience, travelers can get from origin to destination through some combination of public transit, ride-hailing, car-share and/or micro-mobility modes. Public transit lines are often seen as the “backbone” of a MaaS system, where the shared mobility modes could mitigate the “first mile” or “last mile” problem associated with commuter rail systems.