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RESEARCH TRIANGLE LOGISTICS PARK TRAFFIC IMPACT ANALYSIS <br />Capacity Analysis <br />June 4, 2020 <br /> 29 <br /> <br />6.4 2023 BUILD-IMPROVED CAPACITY ANALYSIS <br />The following sections analyzes traffic with the recommended improvements in place. These improvements are <br />detailed in section 8.0. The results of the analysis show that operations are improved at the following intersections <br />within the study area: <br />x Old NC 86 at I-40 Eastbound Ramps; <br />x Old NC 86 at Service Road; and <br />x Old NC 86 at Davis Road. <br />Heavy left-turning traffic is noted on the southbound approach to the intersection of Old NC 86 at the I-40 Eastbound <br />Ramp. The proposed development does not add vehicles to this turn. The analysis of this proposed signal is <br />performed conservatively using protected-only left-turn treatments per North Carolina Department of Transportation <br />Congestion Management Capacity Analysis Guidelines. It is likely that this left-turn will be designed and operated <br />with a flashing yellow arrow; which would improve operations. <br />Queues were observed to extend along Old NC 86 from the I-40 Eastbound ramps beyond the Service Road. This <br />impediment creates longer queues on the Service Road. As discussed previously, operating the southbound left-turn <br />at the intersection of Old NC 86 at I-40 Eastbound Ramp with a yellow flashing arrow would allow more efficient left- <br />turn operation in addition to increasing the green time given to the northbound through movement. This reallocation <br />of green time would lessen the time during which queues block left-turning traffic from the Service Road onto Old NC <br />86. Furthermore, if long delays occur during peak periods, it is possible for traffic exiting the development to utilize <br />access onto Davis Road. <br />It should be noted that the southbound right-turn from Old NC 86 onto the Service Road meets the requirements for <br />an exclusive right-turn lane according to the chart contained in the North Carolina Department of Transportation <br />Policy on Street and Driveway Access to North Carolina Highways. A right-turn lane is not recommended as the <br />right-of-way does not appear to be available to construct this lane. Delay is anticipated to be minimal on this <br />approach as the southbound right-turn is free-flowing. <br />No improvements are recommended at the intersection of Old NC 86 at I-40 Westbound ramps. The westbound left- <br />turn operates at LOS F with the addition of the proposed development traffic. However, SimTraffic maximum <br />observed queues are less than the current 225 feet of provided storage in both the AM and PM peak hours. It is not <br />uncharacteristic of stop-controlled approaches to unsignalized intersections to operate at failing levels of service <br />during the peak hours and it should be noted that the westbound right-turn flows freely. It should be noted that all <br />other movements operate at LOS B or better at this intersection. <br />Table 7 lists the results of the capacity analysis with the recommended improvements in place. <br />152