EXHIBIT 4-2_55A_BRISTOL WIDENING TECHNICAL STUDIES

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Based upon this estimate, Table 3 -2 provides the vehicle emission projections from diesel construction equipment. As shown there- in, over the construction period the following could be emitted: 38 pounds of Co, 15 pounds of HC, 178 pounds of NOx, 13 pounds of SOx, and 11 pounds of particulates, daily. TABLE 3 -2 CONSTRUCTION EQUIPMENT EMISSIONS1 Primary Pollutant Pounds per Day j Co 38.1 THC 15.0 N0x 178.4 Sox 13.1 d Particulates 10.7 r 1. See page 8 of the Appendix for assumptions and calculations. Exhaust emissions during the construction activities will vary from day to day as construction activity levels change but should be minimal and dispersed without significant impact on sensitive receptors. The construction crew will generate an insignificant amount of air pollutants along the various site access routes. Long -Term Pollutant Emissions Long --term impacts are those associated with the change in usage of Bristol Street that will result from the roadway widening. Emission projections can be made for current conditions (1987) and future design year conditions (2006) by multiplying antici- pated motor vehicle usage rates with and without the project by the appropriate emission factors. The emission factors used (see page 8 of the Appendix) were taken from the ARB EMFAC6D model which adjusts the EPA "Mobile Source Emission Factors" to reflect the more stringent emission requirements of California vehicles. Vehicle miles of travel (VMT) and average route speeds are typi- cally the basis for estimating the change in air pollutant emis- sions associated with a roadway improvement project. Traffic data provided by Willdan Associates representing current and future conditions indicated changes in average route speeds but no change in design year VMT values with and without the project. The average route speeds for both current and future conditions are detailed in Table 2 -2 on page 2 -2. 3-7