New Jersey is continuing its efforts to meet the NAAQS by investigating emission reduction strategies for school buses. To quantify idling emissions, 33 tests were performed in an environmental chamber and 36 tests were performed on a test track using a cycle created from GPS data from actual school bus routes. There are currently ∼ 11,000 school buses in use in the state. The current New Jersey school bus fleet produces ∼ 9.3 million kg CO2, 90,000 kg CO, 150,000 kg NOx, 35,000 kg hydrocarbon (HC), and 2145 kg particulate matter per school year. As ambient temperature increased, CO emissions decreased due to a more complete conversion of CO to CO2. Ultra low sulfur diesel had little or no effect on HC, NOx, or CO2 emissions, but considerably decreased CO emissions. This is an abstract of a paper presented at the 2004 AIChE National Spring Meeting (New Orleans, LA 4/25-29/2004).