Date of Award:


Document Type:


Degree Name:

Master of Science (MS)


Civil and Environmental Engineering

Committee Chair(s)

Ziqi Song


Ziqi Song


Patrick Singleton


Haitao Wang


Transportation is one of the most significant contributing sectors to emissions and consequently air pollution in the United States. Many state and private fleet agencies have announced their visions of zero-emission fleet programs. Adopting alternative fuel vehicle (AFV) is a viable option for achieving this objective. AFVs offer lower emissions along with low operating and maintenance costs, and higher fuel economy. The advancement of technologies has provided several AFV options, such as hybrid electric vehicles (HEV), electric vehicles (EV), compressed natural gas vehicles (CNGV), and liquefied petroleum gas vehicles (LPGV). The main challenges in adopting AFVs are the high purchasing cost, lack of adequate infrastructure, and the uncertainty of future fuel cost.

This study aims to introducing AFVs in the fleet while minimizing the life-cycle cost by utilizing an optimization replacement model. To account for the uncertainty of the fuel prices, the rolling horizon (RH) approach has been adopted for the optimization model. This RH approach considers the updated parameters and data while adjusting the vehicle replacement decisions. This study found purchasing price, variations of fuel price and daily activity (miles driven per day) of vehicles as the most significant factors for the vehicle replacement decisions. The study also showed that RH model can provide more cost-efficient fleet composition decisions compared to other models currently being used.