TY - CHAP
T1 - Does Taxing TNC Trips Discourage Solo Riders and Increase the Demand for Ride Pooling? A Case Study of Chicago Using Interrupted Time Series and Bayesian Hierarchical Modeling
AU - Abkarian, Hoseb
AU - Hegde, Sharika
AU - Mahmassani, Hani S.
N1 - Funding Information:
The author(s) disclosed receipt of the following financial support for the research, authorship, and/or publication of this article: This work is based on internal funds provided by the Northwestern University Transportation Center.
Publisher Copyright:
© National Academy of Sciences: Transportation Research Board 2022.
PY - 2023/1
Y1 - 2023/1
N2 - This paper studies the tax intervention applied to transportation network company (TNC) trips starting on January 6, 2020 in the City of Chicago. An interrupted time series (ITS) with an autoregressive integrated moving average (ARIMA) methodology is employed to infer the causal impact of the intervention on the percentage of shared trips and the counts of shared and private trips. Analysis is conducted at a community area level, either as pickup or drop-off. The results show a significant but small increase in the share of shared trips as well as the count of shared trips, specifically on weekends because of the intervention. Private trips, on the other hand, are found to have decreased on the weekdays, but potentially increased on the weekends. A Bayesian hierarchical model is then employed to combine information across community areas, examine a pos-teriori if there are significant spatial differences, and estimate the common treatment effect. The analysis suggests minimal spatial differences across community areas. The common treatment effect on weekdays ($1.75 tax difference) is a 3.78 percentage point increase in the share of shared trips, a 27% increase in the count of shared trips, and a 12% decrease in the count of private trips (at an approximate base of 10% market share of shared trips). Thus, the intervention likely shifted demand toward pooled rides, reducing congestion caused by TNCs. However, there is little evidence that this shift is sufficient to offset or reverse the systematic trend of declining use of shared rides.
AB - This paper studies the tax intervention applied to transportation network company (TNC) trips starting on January 6, 2020 in the City of Chicago. An interrupted time series (ITS) with an autoregressive integrated moving average (ARIMA) methodology is employed to infer the causal impact of the intervention on the percentage of shared trips and the counts of shared and private trips. Analysis is conducted at a community area level, either as pickup or drop-off. The results show a significant but small increase in the share of shared trips as well as the count of shared trips, specifically on weekends because of the intervention. Private trips, on the other hand, are found to have decreased on the weekdays, but potentially increased on the weekends. A Bayesian hierarchical model is then employed to combine information across community areas, examine a pos-teriori if there are significant spatial differences, and estimate the common treatment effect. The analysis suggests minimal spatial differences across community areas. The common treatment effect on weekdays ($1.75 tax difference) is a 3.78 percentage point increase in the share of shared trips, a 27% increase in the count of shared trips, and a 12% decrease in the count of private trips (at an approximate base of 10% market share of shared trips). Thus, the intervention likely shifted demand toward pooled rides, reducing congestion caused by TNCs. However, there is little evidence that this shift is sufficient to offset or reverse the systematic trend of declining use of shared rides.
KW - MaaS
KW - mobility as a service
KW - planning and analysis
KW - public transportation
KW - ride hailing
KW - ridesharing
KW - shared
KW - shared mobility
KW - transportation network companies (TNC)
UR - http://www.scopus.com/inward/record.url?scp=85145346724&partnerID=8YFLogxK
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U2 - 10.1177/03611981221098665
DO - 10.1177/03611981221098665
M3 - Chapter
AN - SCOPUS:85145346724
T3 - Transportation Research Record
SP - 212
EP - 223
BT - Transportation Research Record
PB - SAGE Publications Ltd
ER -