Capacity and Level of Service at Unsignalized Intersections Final Report Volume 1 - Two-Way-Stop-Controlled Intersections (1996) / Chapter Skim
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Chapter Ten. Recommended Computational Procedures
Chapter Ten. Recommended Computational Procedures
Pages 123-134
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From page 123... ...
Number of through lanes on Me major street: N per direction. Major street left turn has shared lanes or blocks rank ~ flows: saturation discharge flow for major through and major right turns S2&3, S58~6 Number and use of lanes on the minor street approaches.
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From page 124... ...
Movement Ranks Step 3 - Determination of Critical Gap and Follow-up Time Determination of the critical gaps and follow-up times for each minor steam movement is based on Table 54 and Table 55, which account for Me effect of grades on the minor approach, 2-stage gap acceptance if applicable, and heavy vehicles. Table 54.
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From page 125... ...
The algorithm is used to disperse a platoon departing at sanction flow rate from the upstream signal. The "spread ratio" at the TWSC location is defined as ache ratio between the time the dispersed platoon occupies at the TWSC location and the time that the platoon required to discharge Dom the upstream signal.
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From page 126... ...
=5,ifi=4; k=3,ifi= 1; =6,ifi=4, Sj is the saturation flow rate for major s~eet through traffic streams Sk is the saturation flow rate for major street right turn traffic Step 6. Computabon of Impedance by Pedestrians for Minor Street Approach Movements Step 6.~.
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From page 127... ...
Step 9.L Compute total conflicting volume Vce7 and Vat lo . Step 9.2.Compute potential capacities(cp,, cp1O)
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From page 128... ...
has to be used to calculate the total capacity for the minor street left turn and through movements 7 and 8, or 10 and ~ (see step ~l)
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From page 129... ...
129 1.0 0.9 0.8 0.7 0.6 a, 0.5 0.4 0.3 ~ .~> 0.1 0.0 Figure 72. Tw~Stage Gap Acceptance, k~1 ~ k- 1 ~ i ,~ ~ .
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From page 130... ...
Note: CSH is Me capacity of shared lane, veh/hr; Vat is the volume of left turn movement In shared VT is we volume of through movement in shared ~ = 3600 + 90~}T ': Vr lane, veh/br; VRis We volume of r~ghtt~n movement In shared lane, vehlhr, cat is the interim capacity of led turn movement in shared lane, veh/hr; CAT is the interim capacity of Trough movement In shared lane, veh/hr, If were is a flared lane on a minor shared approach, then d should also be calculated for each movement as if they had exclusive lanes; If upstream signal effect was included (step 4) , then equation IS3 may overestimate random delay.
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From page 131... ...
Step 14.3. Determine the weighty average total delays and LOS aggregated for ad delayed vehicles, including 1be delayed rank ~ vehicles, in the entire intersection Step 14.4 Determine the weighted average total delays and LOS for aggregated for all movements, including undelayed rank ~ vehicles, In We entire ~ntersechom Table 58.
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From page 132... ...
average delay per vehicle from step 14.1 average queue Dom step 15 volume/capacity Lookup the above three parameters on Figure 75 to obtain a comprehensive assessment of the performance of the critical movement or lane group. This step may also be repeated for any lane group.
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From page 133... ...
... Average Queue 10 .
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From page 134... ...
134 lo.,
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