Abstract
This paper presents a case study examining emissions impacts of a modal shift from on-road trucks to rail for goods movement through the Southern California ports region, one of the severest nonattainment areas in terms of national air quality standards. Recent completion of the Alameda Corridor, a 20-mile rail expressway connecting the Ports of Long Beach and Los Angeles with rail main lines near downtown Los Angeles, provides substantial reserve capacity for port traffic to be diverted from the severely congested road network to the rail line. On-road vehicle emissions were estimated using California’s mobile-source emissions model EMFAC that incorporates a set of emissions factors for each vehicle type and an estimate of vehicle activity. These emissions were then compared with the emissions generated from trains increased to carry freight volume diverted from truck traffic. On the basis of year 2000 traffic level, it was estimated that for a 20% modal shift of port traffic, mobile-source emissions can be reduced up to 0.86 tons for nitrogen oxides and 16 kg for particulates/day. The analysis results indicate encouraging the modal shift for port-related freight traffic should be an integral part of overall air quality improvement initiatives for the study area.
