An Analysis of Air Pollution Impacts from PierPASS in the Alameda Corridor, California

Freight movement is critical to prosperity, but it also generates substantial external costs such as additional congestion and air pollution. One possibility to mitigate congestion and air pollution from urban freight is to shift freight deliveries to off-peak hours but the environmental benefits of this approach are still uncertain. The purpose of this paper is to start filling this gap by analyzing the impacts on the emissions of selected air pollutants of the PierPASS program, which was implemented in 2005 for drayage trucks serving the San Pedro Bay Ports (SPBP, ports of Los Angeles and Long Beach). The analysis combined TransModeler (a microscopic traffic simulation software) with Motor Vehicle Emissions Simulator (MOVES) to simulate traffic for 24 hours on freeways and arterials in the study area, which extends from the SPBP complex to downtown Los Angeles. Overall, it was found that PierPASS had little impact on congestion in the study area and likely resulted in a small decrease in the emissions of various air pollutants, ranging from -0.1% for carbon monoxide (CO) to -2.3% for particulate matter (PM10). At the same time, while the emissions of air pollutants decreased by approximately 10% for NOx and PM during peak time, they increased by approximately 28% for these same pollutants during off-peak hours compared to pre PierPASS levels. Additional analyses are needed to assess the health impacts of these changes for local residents.