TNCs provide on-demand mobility service that either complements or competes with transit services. This article studies how TNCs influence changes in urban travel patterns as well as energy and environmental implications.

“We estimate the effect of on-demand ride-hailing service market entry by Transportation Network Companies (TNCs) Uber and Lyft on per-capita vehicle ownership, energy use, travel distances, and emissions in U.S. states from 2005 to 2015 using a difference-in-difference propensity score-weighted regression model. We find evidence that TNC entry appears to cause a decline in state per-capita vehicle registrations by 3%, on average (95% confidence interval: 0.7–5.5%). Our results regarding travel distances, gasoline consumption, and several air pollutants are not conclusive, but we find evidence of a negative relationship with some EPA-estimated vehicle air emissions, representing a decline of $300 million to $900 million in externalities during the analysis period. However, these air emissions data are modeled, rather than directly measured, so we are cautious about causal interpretations, and uncertainty in the effects of TNC entry on travel distances and gasoline consumption suggests potential additional externality effects that could dominate the air emissions effect.”

Key findings

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“Our results suggest that access to TNC services appears to cause a reduction in per-capita vehicle registrations in U.S. states. Interpreting this effect as causal relies on two key assumptions: (1) trends in outcomes of interest would have been parallel across treatment and control states in the absence of Uber entry, and (2) treatment (Uber entry) was exogeneous.”

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“Our results also suggest a relationship between TNC entry and VOC emissions of highway vehicles as estimated by the EPA, and these results pass our robustness checks, but we are cautious about interpretation because the dependent variable is modeled rather than measured and has several years of interpolated values. We view this finding as exploratory, indicating potential value in further study of TNC implications for emissions. We do not identify robust, statistically significant effects of TNC entry on gasoline consumption, vehicle miles traveled, or emissions other than VOCs, but this does not imply that TNCs have no effect on these outcomes.”

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“We estimate that TNC service availability in U.S. cities has reduced state per-capita vehicle ownership by 3.1% on average during the period 2005–2015 (relative to expected trends if the TNCs had not entered). This effect is estimated at the state level, though TNC market entry and ridership is generally an urban phenomenon. An effect of this magnitude would correspond to a reduction in vehicle ownership of 4.1%, on average, across all urban areas (assuming no effect in rural areas).”

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