Morrisville Administrative Manual_September 2023

Part 4. Appendices 4.10.2 Analysis Standards

b. Internal capture reduction shall be applied before the pass-by trips are calculated.

2.

Pass-by Trips

a. Pass-by percentages shall be obtained from the most recent edition of the ITE Trip Generation Manual; b. Pass-by trips shall not exceed 10% of the total volume on the adjacent street; and c. All efforts should be made to ensure that upstream and downstream traffic volumes along corridors balance and maintain continuity. If balanced volumes are not attainable, an explanation should be provided. Documentation regarding the balancing methodology should be provided as well. 1. Present signal timings including coordination and phasing shall be used for the existing conditions analysis; 2. Optimized signal timings and phasing can be proposed as a part of a Build Improved scenario if it can be shown that the signal timings and phasings can be optimized without degradation elsewhere along the corridor; 3. A peak hour factor of 0.90 shall be applied for all cases except existing traffic when traffic counts have been acquired; 4. Zero right turns on red shall be used for signalized intersections as a worst-case scenario; 5. Minimum five-second yellow two-second all-red clearance interval and a -2 second lost time adjustment, or the actual timing of any existing signal(s) shall be used; 6. Minimum seven-second green time per phase for left turns or the actual timing of any existing signal(s) shall be used; 7. Minimum green time for through movements as specified by NCDOT or the actual timing of any existing signal(s) shall be used; 8. Base Saturation Flow Rates and Lane Utilization Factors shall be used in accordance with the latest edition of the Highway Capacity Manual. Lane Utilization shall be accounted for when one or more lanes drop less than 1,000 feet from an intersection); and 9. Minimum signal cycle lengths as listed in Table 4.10.2.G, Minimum Signal Cycle Lengths, shall be used:

G. Signal Analysis

All signals shall be analyzed. The following assumptions with supporting data are required:

Table 4.10.2.G: Minimum Signal Cycle Lengths

Number of Phases

Minimum Recommended (seconds) [1]

2 3

60 90

4 or more [2]

120

Notes:

[1] All cycle lengths should be rounded to the nearest 5 seconds. [2] Traffic Signal Timing Manual (FHWA) for planning level analysis.

Morrisville, NC

August 7, 2023

Administrative Manual

Page 101