AgdaPkt 2000-08-28 - Laserfiche WebLink

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lOA' accordance with Highway Capacity Manual procedures. Table 1 presents the results of that analysis. TABLE 1: Intersection Volume/Capacity and Delay Comparison Location Volume/Capacity Ratio Delay per Vehicle (sec) Before After Before After Alameda & Whipple - AM. .862 .827 23.6 19.2 - P.M. .849 .856 22.7 23.5 Alameda & Edgewood - AM. 1.0+ 1.0+ 202.7 179.8 - P.M. 1.0+ 1.0+ 190.8 132.4 The results of the Level Of Service Analysis show that after the humps were installed, conditions actually improved at the intersection of Alameda de las Pulgas and Whipple in the AM. peak and at Alameda de las Pulgas and Edgewood in both AM. and P.M. peaks. There was a slight decrement to Volume-to-Capacity ratio, and average delay at Alameda-Whipple in the after condition for the P.M. peak. However, the changes of .007 vlc and 0.8 seconds delay are nowhere close to the significance of thresholds of .05 v/c and 5.0 seconds delay. The decrements that were measured would not even be perceptible to the typical motorist. The Level Of Service computations also evaluated queue length at both intersections. The results show no queue changes that would have any significant adverse effects on traffic operations was experienced. TRAFFIC SPEED FiGures 3. 4 and 5 present critical comparisons of speed data taken before and after hump installation. Figure 3 shows comparisons of eighty-fifth percentile speed before and after on Edgewood, as well as on nearby local streets including Blandford Boulevard, Arlington, Turnsworth, and Woodsworth. Eighty-fifth percentile speed is the speed not exceeded by 85 percent of all drivers on the given street segment. It is significant in traffic engineering theory and in law because it is held to be the speed not exceeded by reasonable drivers acting with due care. Speed limits are normally set at the closest 5 mph increment to the measured eighty- fifth percentile speed and, except in special circumstances, courts will not enforce citations based on speed limits' set more than the closest 5 mph increment below the eighty-fifth percentile speed. The data on Figure 3 shows that the eighty-fifth percentile speed on Edgewood at the fastest point on the street was in excess of 35 mph before the humps were installed, and dropped to 28.7 mph after the humps were in place. The figure also shows that the speed conditions on Blandford were benefited by the stop signs that were installed simultaneously with the humps on Edgewood, with eighty-fifth percentile speed dropping from about 31 mph before to 28.5 mph after the controls were in place. In addition, the figure shows that eighty-fifth percentile speeds on both Edgewood and Blandford were brought into conformity with that on other nearby local residential streets and that none of the other local streets experienced significant non-beneficial effects as a result of the traffic control changes. Figure 4 shows the average number of vehicles per day driving 10 or more mph above the 25 mph speed limit on Edgewood Road and on adjacent local residential streets before and after -3-