Document Type

Journal Article

Publication Date


Subject Area

ridership - forecasting, ridership - forecasting, technology - alternative fuels, mode - bus, mode - school bus


Transit buses, State laws, School buses, Scenarios, Projections, Pollution control, Particulates, North Carolina, Nitrogen oxides, Forecasting, Cost benefit analysis, Benefit cost analysis, Alternative fuels, Alternate fuels


North Carolina Senate Bill 953 enacted April 14, 1999, established a goal to reduce nitrogen oxide and particulate matter emissions in North Carolina. The legislation mandates that 50% of all replacement and expansion transit and school bus purchases in specific counties after January 1, 2004, shall be alternative-fueled, low-emission buses. The estimated emissions and costs in purchasing and operating various alternative-fueled, low-emission transit buses between 2004 and 2009 are addressed. A 1999 current emissions baseline scenario was developed to provide a basis for comparing the estimated emissions from four hypothetical scenarios for 2009. One scenario, the 2009 baseline emissions scenario, estimates emissions in 2009 if North Carolina transit fleets continue to purchase only diesel-fueled buses operating at current levels of emissions. The remaining scenarios estimate emissions assuming that 50% of transit bus purchases between 2004 and 2009 will be alternative-fueled, low-emissions buses. Estimates of the costs to purchase and operate alternative-fueled, low-emission buses were developed corresponding to the four 2009 emissions scenarios. A rudimentary benefit-cost analysis was conducted to estimate the cost per ton avoided for each of the four U.S. Environmental Protection Agency criteria pollutants. The benefit-cost analysis indicated that emissions reduction from diesel engines could surpass those from current natural gas-powered buses at a fraction of the cost.