EXHIBIT 4-2_55A_BRISTOL WIDENING TECHNICAL STUDIES

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Bristol right -of -way and 50 feet from the First Street right -of- way. The CA140 Headstart State Preschool lies 250 feet north of the First Street centerline with the playground at the Bristol. right -of -way. The closest SFD to this intersection lies 380 feet south of the First Street centerline at 10 feet from the Bristol right -of -way. At the Bristol /Warner intersection, the closest sensitive recep- tors are residential land uses. one SFD lies 200 feet east of the Bristol Street centerline adtjacent to the Warmer Avenue right -of -way. A second SFD lies 500 feet north of the Warner Avenue centerline at 2205 Bristol Street. The Bristol Place multifamily apartment complex lies `200 feet west of the Bristol Street centerline on Warner Avenue. The Caline 3 modelling shows a substantial decrease in the 1 -hour and 8 -hour average Carbon monoxide concentrations at all recep- tors at the intersections analyzed as a result of the roadway widening proposed. The carbon monoxide concentrations with the project are lower than those with the No Project Alternative because the benefits of increased speeds mere than offset the detrimental effects of a wider cross-section. l Currently, the background 1 -hour carbon monoxide concentration (18.0 ppm) is below the state and federal standards. however, the 8 -hour average background concentration [11.7 ppm] presently exceeds both state and federal standards. Year 2006 1 -hour background concentrations (14.6 ppm) are projected to be well below the relevant state and federal standards. Ambient 8-hour CO levels in the year 2006 (9.5 ppm) are expected to exceed both state and federal standards (9.0 ppm; see Appendix for methodolo- gy). At present, sensitive receptors in the project vicinity appear to experience carbon monoxide levels that exceed state and federal standards. -Under future conditions with the project, sensitive I land uses adjacent to the intersections analyzed will be setback ll far enough from the intersectionb to allow dispersion of pollu- tants and significantly reduce the number of receptors exposed to high concentrations of carbon monoxide. Since only "worst case" conditions were considered in Table 3 -4, carbon monoxide concen- trations during conditions which are more likely to occur should be less than those shown. Air Quality Management Plan The 1982 Revision of the Final AQMP includes projections of future carbon monoxide levels in the South Coast Air Basin. The second highest 8 -hour average forecast is 9.5 ppm by the year 2000. Based upon these projections {which assume that the AQMP ----- ---- -- -- - - -- -- I. The higher speeds resulting from more efficient traffic 3 -12