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. Bowers Museum Expansion Responses to Comments 4/27104 Response: Attachment A of this memorandum includes an analysis completed in accordance with the analysis procedures of the 2000 Highway Capacity Manual (HCM) for the intersections included in the study area that are related to Caltrans facilities. As shown in Table 1 (LOS Summary) in Attachment A, both intersections are projected to operate at acceptable levels of service under future conditions with and without the subject project based on the 2000 HCM analysis procedures. It should be noted, the Level of Service (LOS) E is acceptable for intersections in Major Development Areas. Table 2 of Attachment A summarizes a comparison of the LOS analysis results based on the Intersection Capacity Utilization (ICU) methodology and HCM methodology. As shown, there are three cases in which the HCM methodology results are different from the ICU methodology. However, the results are actually very close. For the intersection #4 under the existing conditions, the ICU result (0.699, B) is at very high range of LOS B criteria, but the HCM result (26.4, C) is at low range of LOS C. Refer to Table 3 for the LOS criteria used for both the ICU and HCM Methodologies. For the intersection #4 under the condition of 2005 without project, the ICU result (0.903, E) is at very low range of LOS E criteria, but the HCM result (51.3, D) is at high range of LOS D criteria. Similarly, for the intersection #5 under the existing conditions, the ICU result (0.590, A) is at very high range of LOS A criteria, but HCM result (15.7 B) is at low range of LOS B criteria. . Detailed LOS worksheets for the HCM analysis are included in Attachment B. The HCM methodology and ICU methodology resulted in different LOS results for three cases because the intersections were operating near the thresholds of changing from one LOS to another. However, the differences in LOS will not change the analysis results because they are all at acceptable level of service. It should be noted, the ICU and HCM methodologies use different measures of effectiveness for signalized intersections. The ICU is primarily based on volume-to-capacity ratios and the HCM is based on a measure of delay. Typically, a comparison of the two different methodologies will provide similar LOS results. Comment 3 - Please included the intersection at the northbound (NB) off-ramp and Main Street as part of the traffic analysis; Response: As shown in Figure 2.6-2 of the Traffic Impact Study Report, at intersection #5, 21 project vehicles go north and 23 project vehicles go south. A total of 44 vehicles will be generated north of intersection #5. Therefore, intersections to the north of intersection #5 (including the intersection of Main St. and 1-5 NB off-ramp) were not included because they were below the 51 trip threshold. Definition of the study area is further discussed in Section 1.3 of the Traffic Study. . P&D Consultants, Inc. An.AECOM Company Page 4 of 17 Page 2 of 5 758-29