Ride-hailing companies such as Uber and Lyft are increasing not just traffic but greenhouse gas emissions (GHGs) in Greater Boston, new data shows. The first-ever analysis of the climate impacts of transportation network companies, or TNCs was conducted by the Boston area's Metropolitan Area Planning Council (MAPC).

Using recently-released data from the state’s Department of Public Utilities (DPU), which tracks TNC trip data in Massachusetts, MAPC researchers calculated the effect of ride-hailing services on vehicles miles traveled (VMT) and greenhouse gas emissions across Greater Boston. DPU data for the state as a whole, the City of Boston, and individual municipalities in the region are available online at https://tnc.sites.digital.mass.gov.

MAPC found TNCs released an estimated total of 163,300 metric tons of CO2e, which is the equivalent of over 18 million gallons of gasoline consumed. Additionally, the MAPC analysis found that TNCs divert riders from public transit, costing the MBTA an estimated $20 million each year.

“We already know that TNC services are siphoning riders and dollars from public transit, but now we can see clearly that they leave an impact on our congestion as well as our air quality,” said Rebecca Davis, Deputy Director of MAPC, the regional planning agency serving Greater Boston. “Clearly we need to do more to promote shared trips when users choose these services, while advocating for better walking and biking infrastructure and safe, reliable public transit.”

Between 2017 and 2018, the number of ride-hailing trips grew from 64.8 million to 81.3 million, a 25% increase across Massachusetts. MAPC calculated the GHGs by using the number of TNC trips by municipality, and the average miles per trip reported by DPU, applied against earlier research by MAPC that showed almost 60% of ride-hailing trips would have used a non-polluting mode of travel if Uber and Lyft were not an option.

According to MAPC, the negative effects of TNC emissions may be decreased by policies and programs that promote shared trips/ride pooling; providing incentives for drivers to use electric or zero-emission vehicles; and maximize the efficiency of pick-up and drop-off locations.

The study also calls for the state to collect more data on TNCs to better evaluate their impact, giving local planners more effective tools to measure and understand rider behavior.

Lawmakers will host hearings related to TNC regulations this week. Fees on ride-  hailing will be the subject of testimony at a Joint Committee on Financial Services hearing where almost two dozen bills are on the agenda, including several that would increase the 20-cent per ride flat fee now imposed on Uber and Lyft trips.

Another bill by Rep. Adrian Madaro of East Boston would charge companies for congestion-causing “deadhead” rides – those with no passenger – at Logan Airport. Legislation filed last week by Gov. Charlie Baker would impose new safety restrictions and data-collection requirements on ride-hailing companies but is not yet set for a hearing, and has been referred to the Joint Committee on Transportation.