Early transition to cleaner bus fleets: Benefits, costs, and policy evaluation of alternatives from a life cycle perspective

Older urban buses are significant contributors to environmental effects. This study assesses the economic and environmental feasibility of transitioning to cleaner bus fleets by following the concept of early replacement of older buses that are still operational while examining several propulsion alternatives and policy approaches in Israel. Relying on assessments of environmental costs (EC) and the total cost of ownership (TCO), the proposed concept is feasible for all the propulsion systems examined. This feasibility is then reflected in the propulsion systems' marginal social costs (MSC), which are all lower than the MSC of continued reliance on diesel Euro 5 buses that are still operational, as well as in their incremental benefit-cost ratio (IBCR) that is greater than 1.5. Early replacement is an effective measure, reflected primarily in a substantial reduction of air pollution and noise. Electric bus was found to be the best in EC (0.17 USD/vkm) but worst in TCO (1.65 USD/vkm). It was followed by diesel-electric hybrid (EC 0.27 USD/vkm; TCO 1.6 USD/vkm), compressed natural gas (CNG) bus (EC 0.32 USD/vkm; TCO 1.4), and diesel Euro 6 bus (EC 0.33 USD/vkm; TCO 1.61 USD/vkm). Determining which alternative is preferable relies on additional considerations.