COM 0861.000 2008-2010 - Laserfiche WebLink

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County of Hawai' i Department of Public Works - Traffic Division April 7, 2010 TO: FILE (IR 08 -115) FROM: Vince Kasarskis SUBJECT: PUAINAKO STREET EXTENSION SPEED LIMIT RECOMMENDATIONS The posted speed limits for the Puainako Street Extension from Komohana Street to Country Club Road were evaluated. • Speed studies were conducted that indicated that the 85 percentile speeds were well above the posted speed limits (62 MPH in the posted 35 MPH area and 64 MPH in the posted 45 MPH area). • The curves along the entire length were tested at proposed speed limits with a ball bank meter. • Each horizontal curve was reviewed and the design speeds exceed the proposed speed limits by a minimum of 5 MPH for each horizontal curve. • Each vertical curve was reviewed. At three (3) vertical curves, the proposed speed limit will match the design speed. • The intersection sight distance at Wilder Road was field measured. This field measurement limits the speed limit of Puainako Street at the intersection to a posted speed of 40 MPH. Intersection sight distance for a vehicle facing Hamakua and executing a left turn onto Puainako Extension (heading toward Waimea) could be increased to allow a posted speed limit of 45 MPH on Puainako Street Extension by raising the Hamakua bound side by approximately 0.35 feet. Raising a portion of the intersection would require adjusting the grade of the entire intersection to allow proper drainage off the major road, Puainako Street. • There will be a realignment project for Saddle Road between milepost 6 to milepost 1 1 . The design speed and posted speed of this realigned section may support justify adjusting the grade of the Wilder Road intersection to minimize the number of speed changes. For existing conditions, the following recommendations are made: 1. Raise the posted speed limit from 35 MPH to 40 MPH from STA 2 +00 +/- to STA 77 -+ 75 + /- (approximately 1.5 miles). 2. Raise the posted speed limit from 45 MPH to 55 MPI I from STA 77- + -75 +/- to Komohana Street (STA 251 +10 + / -) (approximately 3.3 miles). The speed limit heading makai (toward Hilo) will be reduced to 35 MPH approaching the Komohana Street traffic signal. The speed limit evaluation of Puainako Street Extension was coordinated with State Traffic Engineer, Alan Takeshita, who had no exceptions. County of Hawaii is an Equal Opportunity Provider and Employer.