New York City Fleet Upgrades: Conventional Diesel, Hybrid, or CNG?In Media Res Cost-Benefit Analysis

Based on the case study of the New York City Transit Authority, this paper completes an in media res cost benefit analysis (CBA), from a societal point of view, of upgrading their fleet to cleaner buses. The three alternatives considered in the CBA are renewing the fleet with: (i) traditional diesel buses, (ii) hybrid-diesel buses, and (iii) compressed natural gas (CNG) buses. The analysis has been done on a per bus per year basis, with a time frame of 30 years. Impacts such as vehicle operation and maintenance, capital investments, emissions reductions, and energy security impacts have been taken into account. Different scenarios have been used to perform a sensitivity analysis. Results show a higher net present value for CNG buses than for hybrid or conventional diesel buses in almost every scenario. Yet, these results are heavily dependent on the price of gas; the willingness to pay more in order to not be dependent on foreign oil, and on the price society is willing to pay to reduce greenhouse gas emissions.