To date, a small body of research has attempted to quantify the relationship between ride-hailing, Vehicle Miles Traveled (VMT) and GHG emissions. One recent report² analyzed and compared thirteen studies that researched this issue and concluded that ride-hailing is likely to increase VMT and associated GHG emissions for a variety of reasons. Researchers posit that these increases may result from induced trip generation; empty travel to pick up passengers; and substitution of ride-hailing for trips that would have been made by taking public transit, walking, or bicycling. However, there has been little progress in estimating the total magnitude of increased GHG emissions associated with ride-hailing.

There is good reason to be concerned about the climate impacts of ride-hailing. Transportation is the largest and fastest-growing producer of GHG emissions. In Massachusetts, 43 percent of GHG emissions in 2016 came from transportation infrastructure and vehicles.³ Nearly half of this contribution (20 percent of total GHG emissions, or approximately 15 million metric tons of CO₂ equivalents) came from passenger vehicles alone⁴ (the rest of the emissions are attributable to light- and heavy-duty trucks, aviation, and rail.)

Ride hailing constitutes an increasing share of passenger transportation travel. Between 2017 and 2018, the number of ride-hailing trips grew from 64.8 million to 81.3 million, a 25 percent increase across the Commonwealth. MAPC’s 2018 report Share of Choices⁵ estimated that ride hailing comprised approximately 1.3 percent of all trips in the MAPC region in 2017. Using new data recently released by the DPU, we estimate that the ride hailing “mode share” climbed to 1.7 percent of all trips in the region in 2018.

The newly available data include average trip mileage based on municipality of origin, also allowing us to produce the first estimates of net GHG emissions generated by ride-hailing trips in Massachusetts. These data show that ride-hailing “revenue miles” for passenger trips totaled almost 400 million miles statewide 2018. Based on this figure, we estimate that ride-hailing trips consumed over 18 million gallons of gasoline and produced a total of 163,300 metric tons of CO₂ equivalents in 2018.⁶ Of course, not all of these are ‘new’ emissions, since many trips would have been made by car anyway even if ride-hailing were not available. MAPC’s report Fare Choices⁷ used survey data to conclude that approximately 60 percent of ride hailing trips would have been taken by transit, walking, or biking, or would not have happened at all, if ride-hailing were not available. After accounting for this mode shift from less carbon-intensive modes, we estimate that the net carbon footprint of ride hailing was 96,340 metric tons of CO2 equivalents in 2018. This is a conservative estimate as it does not include times ride-hailing vehicles spend deadheading or driving while waiting for trips to be assigned.

This net carbon footprint is approximately 0.6 percent of the carbon emissions estimated for the MA passenger vehicle fleet in 2016. In other words, even as the state is working to implement policies that will encourage more sustainable modes of transportation, it is experiencing rapid growth in an industry that is adding to the carbon impact of the state.