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-� <br />Debra Bloom, P.E. <br />City of Roseville <br />� <br />October 29, 2007 <br />Page 2 <br />We conducted a trip generation comparison for retail developments with lower square <br />footages. Using the average rate in the ITE Trip Generation Reports results in significantly <br />lower trips than using the fitted curve equation. In reviewing the data points presented in the <br />ITE Trip Generation Reports, the data points for a shopping center development with lower <br />square footages coincide more closely with the fitted curve line, rather than the average rate. <br />Using the fitted curve equation results in more that twice the number of estimated trips. A <br />balance between these two is necessary to ensure that an appropriate trip generation estimate <br />is used as part of the traffic analysis. <br />There are inconsistencies with the number of screens that are documented in the report text <br />and the trip generation estimates for the existing movie theater. The correct number shou(d <br />be identified in the report. For the movie theater, the trips were based on the number of <br />screens. Based on our experience, a better estimate of trips for movie theaters is the number <br />of seats. <br />On page 5 of the traffic study, it is stated that a conservative approach was taken in <br />estimating the trips for parcels 81A, 81B and 81C. It is stated that the current plan proposes <br />81A as 3,300 square feet and 81B and 81C with 3,300 total square feet of general retail. The <br />memo states that the traffic analysis took a"conservative" approach and used sit-down <br />restaurant for the entire 6,600 square feet. However, if this property were in fact used as <br />restaurant space with three different tenants (i.e. coffee shop, sandwich shop, etc.), it would <br />be more appropriate to use a fast-food type land use without a drive thru. This would result <br />in more than twice the number of trips estimated for these parcels. <br />The traffic study documents the use of various reduction factors, including multi-use and <br />pass-by reductions. It appears as though the multi-use reduction was applied to the shopping <br />center rate. The ITE Trip Generation Reports and rates for the shopping center land use <br />already account for this type of reduction. Therefore, this reduction factor should not be <br />applied to this use. <br />The application of the pass-by trip reduction is confusing. The pass-by trips should only be <br />reduced from the through volumes on the roadway affected by the pass-by trip diversion. <br />The trip generation tables provided appear to reduce the amount of trips generated by the <br />mall based on the pass-by trip reduction factor. The amount of trips generated by the mall or <br />other development is not impacted by the amount of pass-by traffic a specific use causes, the <br />trips should still be accounted for entering and exiting the site. Therefore, the driveway <br />volumes should reflect all trips to/from the site, including pass-by trips. <br />• Overall, if the trip generation estimates for the proposed mall redevelopment are <br />underestimated or there is additional background traffic growth in the study area, the impacts <br />to the adjacent roadway system would be understated. <br />