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The product of this review will be a summary of each of the study segments and identification of <br />the study segments which justify consideration for maximum increase/decrease in the <br />recommended speed limits. <br />Task 4 — Accident History Review and Rate Calculations <br />The AGA Team will evaluate the most current mid -block accident history (minimum two years) <br />on each of the street segments included in the survey. For accident history analysis purposes, <br />mid -block accidents are defined as those occurring outside of the 150' radius of signalized <br />intersections of the roadway segment being analyzed. This criterion excludes collisions that may <br />be traffic signal related in nature. We have extensive experience in City traffic operations and <br />are well qualified to review accident records. <br />The mid -block accident rate in terms of "accidents per 1,000,000 vehicle miles of travel" for each <br />segment surveyed will be calculated and shown on the Engineering and Traffic Survey summary <br />sheets. The following shows the accident rate calculation: <br />Accident Rate = Number of Midblock accidents x 106 <br />Where: <br />24-hour volume x 365 x segment length x number of years <br />Number of mid -block accidents based on a minimum of two years <br />24-hour volume (both directions) for the survey segment <br />Segment length in miles <br />As stated in the Santa Ana Speed Survey Q&A Set 1, released July 14, 2021, the City will <br />provide both the accident data and the ADT count information. <br />A minimum two-year accident data is recommended to be utilized to develop Actual Accident <br />Rates for comparison to the Average Expected Accident Rates which is detailed in the 2017 <br />Collision Data on California State Highways (Revised March 2020) published by the California <br />Department of Transportation. The Average Expected Accident Rates per roadway type are <br />summarized below: <br />Roadway Type Average Expected <br />Accident Rate <br />Conventional 2 lanes or less (< 45 mph) <br />1.20 <br />Conventional 2 lanes or less (> 45 mph) <br />0.82 <br />Divided 4 lanes (< 45 mph) <br />0.91 <br />Divided 4 lanes (> 45 mph) <br />0.90 <br />Divided 5 lanes or more (< 45 mph) <br />1.00 <br />Divided 5 lanes or more(> 45 mph) <br />1.06 <br />Example: <br />For a roadway segment with the following information: <br />2 lane roadway <br />• 35 mph posted speed <br />17 midblock accidents/collisions in 3 years <br />_ME <br />I, F,,:,:�,>i,i, . <br />Page 7 <br />