Transportation Network Companies (TNCs), or ride-hail companies, have the potential to reduce emissions by reducing single-occupancy trip distances through pooled rides and reducing the need for private vehicle ownership. Ride-hail services can also support transit use by providing riders with an option to connect to transit stations, and by complementing transit in times and places it does not operate.

Ride-hail services can, in theory, reduce emissions by linking passengers traveling in similar directions. In practice, however, those benefits are limited. Most trips are not pooled; one study found just ten percent of trips were pooled, and 27 percent involved multiple passengers [1]. Deadheading, or trips made with no passenger in the vehicle (often between where one passenger is dropped off and the next is picked up), contributes to additional emissions. A significant portion of ride-hail trip miles (40 percent, from a study of TNCs in Canada) are deadheading trips. Both pooled and unpooled ride-hail trips emit more pollutants relative to trips taken by single-occupancy vehicles [1].

Ride-hail might also reduce emissions by offering an alternative to private vehicle ownership, or by connecting riders to transit stations. The evidence is mixed regarding the extent to which riders substitute ride-hail for public transit, with studies finding that ride-hail reduces net transit ridership between 14 and 58 percent, depending on the city studied and the type of transit [2], [3]. The more abundant and reliable ride-hail becomes, particularly in urban areas with a rich array of alternative travel modes, the more likely people are to willingly shed their private vehicles [4]. Moreover, electrifying ride-hail can go a long way toward reducing greenhouse gas emissions, particularly electrifying vehicles for full-time ride-hail drivers [1], [5].