Item 17 - Appropriation Adjustments for Bristol Improvement Project Phase 4

Home Browse Search

ENVIRONMENTAL IMPACT REPORT ADDENDUM Bristol Street Widening Project Warner Ave to Saint Andrew Place (Phase IV) accurately determine the significance of air quality impacts from construction activities, construction emissions are quantified and compared to the significance thresholds set by the SCAQMD. Project -specific data, such as construction timelines and dimensions of the project site, along with general operating guidelines, were used as inputs to the SCAQMD's California Emissions Estimator Model (CalEEMod) Model (version 2011.1.1) to quantify construction emissions. As shown in Table 3, emissions calculated by this model were compared to the SCAQMD's regional significance thresholds. As shown in Table 3, emissions attributable to construction of the proposed project were found to be below the significance thresholds adopted by the SCAQMD for all the analyzed air pollutants. Because emissions were found to be below the SCAQMD's significance thresholds, project related construction emissions are not considered by the SCAQMD to result in a significant impact. In addition, mitigation measures included in the 1990 Final EIS/EIR would further reduce construction -related air quality impacts. TABLE 3 PROJECT RELATED CONSTRUCTION EMISSIONS C121T1=RlA FOLLIJTAM(S �L�B� lf}AY� j vOC NOx CO ' SO2 PM10 PM2s5 Demolition 8 64 43 <1 12 3 Trenching 4 33 19 <1 2 2 Grading 7 52 31 <1 5 4 Paving 3 15 11 <1 1 1 Maximum 8 64 43 <1 12 3 SCAQMD Threshold 75 100 550 150 150 55 Exceeds Threshold? No No No No No No Source: URS Corporation, January 2011 An assessment of regional emissions associated with the operations phase of the proposed project was also conducted which compared emissions with and without the proposed project. Air pollutant emissions generated by roadway vehicles are quantified based on emissions rates that vary based on vehicle speed. Because the Proposed Project would increase the roadway capacity along Bristol Street, traffic congestion would be alleviated and average vehicle speeds would increase along improved roadway segments. Table 4 shows the emissions that would occur with and without the proposed Project based on the average vehicle speeds. As shown in Table 4, air pollutant emissions would be less under the With Project Alternative as opposed to the No Project Alternative due to the lower emission rates associated with higher average vehicle speeds. The SCAQMD has established significance thresholds to determine whether the operations phase of projects would result in significant impacts to regional air quality. The proposed project would result in air pollutant emissions which are below these significance thresholds and would result in a beneficial impact in emissions due to improvements in operational phase efficiencies along project roadway segments for the 2015 project opening year. Emissions occurring during the 2035 design year were also quantified based on the LOS, average vehicle speed and emission rates that would occur with and without the proposed project. As shown in Table 5, air polhrtant emissions occurring under the With Project Alternative would be less than under the No Project Alternative due to lower emission rates associated with higher average speeds. Consequently, the Proposed Project for the 2035 ANA 305-194 (PER 02) CSA (AUGUST 2014) 133867 YU 25 75C-41