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2 of 7 Traffic Speed and Volume Foothill Road has a daily volume of 8,000 to 12,000 vehicles per day depending on the day of the week and levels of I-680 freeway congestion, which can result in vehicles using Foothill Road as a cut-through route. Traffic volume on Foothill Road is heaviest during the AM and PM commute hours as well as during the 3:00 PM school release time. During these times the volume is normally directionally distributed. As an example, the AM peak hour can have 800 southbound vehicles and 400 northbound vehicles in an hour. When directional vehicle volumes exceed 650 vehicles per hour, the number of gaps in traffic that can be used to access Foothill Road begins to decline. 650 vehicles per hour results in an average spacing of 5.5 seconds per vehicle; 5.5 seconds is the typical spacing needed between vehicles to allow for left turns onto Foothill Road. As directional volumes increase, the spacing between vehicles is reduced. As directional volumes approach 1,000-1,200 vehicles, the line of vehicles becomes nearly continuous and gaps in traffic are infrequent. Data collected prior to the pandemic showed that from 7 AM to 9 AM the southbound volumes exceeded 1,000 vehicles per hour. Northbound maximum hourly volumes approached, but did not exceed, 650 vehicles (maximum northbound volume was also from 8 AM to 9 AM). During these busier morning hours, the left turn access onto Foothill Road may require a driver to wait several minutes to find an adequate gap in traffic. Annual data collection in spring 2024 shows similar AM volumes to the pre-pandemic traffic counts, with the afternoon school and PM commute volumes remaining below the 650-vehicle directional volume. The project trip generation table below compares the vehicle trip generation of an age- restricted senior adult housing project to the vehicle trip generation of a non-age-restricted single family home development. Notably, senior housing projects generate fewer trips than traditional single family home developments. In addition to the lower trip rate, seniors tend to choose to drive outside of the busy peak hours and their peak hour trip rates are also lower than traditional single family home developments. The expected volume generated by the proposed development is 647 daily trips. The AM peak hour (7 AM to 8 AM) and PM peak hour (5 PM to 6 PM) have 42 and 48 trips respectively. These volumes differ slightly from what is shown in the staff report. The staff report volumes used the ITE average trip generation rate, but in this supplemental analysis, the ITE fitted curve equation was used, which provides a more conservative estimate given the proposed development size. The AM peak hour has the highest volume on Foothill Road and the highest volume of vehicles leaving the development with 28 vehicles exiting between 7 AM and 8 AM. The modeling assumes that half of the vehicles will turn right, and half will turn left, giving a total of 14 vehicles wanting to make the left turn during the busiest hour of the day (one vehicle every 4-5 minutes).