Mobile Source Air Toxic (MSAT) Analysis Case Study\u2014 State Route 57/State Route 60 Confluence at Grand Avenue, California

Federal Highway Administration2016PDFExampleFederal Highway Administration (U.S.)Federal Highway Administration (U.S.)United StatesCaliforniaAnalysisCase studiesFreewaysImprovementsAir quality managementFHWA-HEP-16-065The City of Industry, California, the California Department of Transportation (Caltrans), and the Federal Highway Administration (FHWA) proposed freeway improvements to the State Route (SR) 57/SR 60 confluence at the Grand Avenue interchange in Los Angeles County, California. The proposed project was subject to both the California Environmental Quality Act (CEQA) and the Federal National Environmental Policy Act (NEPA). Caltrans served as the lead agency under both CEQA and NEPA. The regional vicinity of this project is shown in figure 1. SR 57 is a major north/south freeway, serving the cities and communities of the Greater Los Angeles area. SR 60 is a major east/west freeway that serves the cities and communities on the east side of the Los Angeles metropolitan area and on the south side of the San Gabriel Valley. There is a gap in SR 57 at its junction with SR 60. SR 57 terminates at the west end of the confluence with SR 60. SR 60, which carries traffic from both freeways, maintains six lanes in each direction under Grand Avenue. SR 57 resumes at the split with SR 60 at the east end of the confluence near Diamond Bar Boulevard. The length of the combined mainline for SR 57/SR 60 is about 2.5 miles.Improvements to the SR 57/SR 60 confluence were needed to improve safety and operational deficiencies at the Grand Avenue interchange. By 2037, freeway operations were forecasted to deteriorate to an estimated level of service (LOS) of F on the mainline of the SR 57/SR 60 confluence in both the westbound and eastbound directions, with volumes 10 to 25 percent higher than existing volumes along the SR 60 mainline and in the recently constructed HOV lanes. The primary objectives of the project were to:104