1 / 13

Signal Design

Signal Design. CTC-340. HMWK. Ch 21 #3, 4, 6. Steps. Convert all volumes to equivalent thru vehicle units T 21.1 , T21.2 show equivalents for LT ,RT traffic volumes Use to find path thru intersection for each phase which has highest volume Determine critical volume for each phase.

olaf
Download Presentation

Signal Design

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Signal Design CTC-340

  2. HMWK • Ch 21 #3, 4, 6

  3. Steps • Convert all volumes to equivalent thru vehicle units • T 21.1 , T21.2 show equivalents for LT ,RT traffic volumes • Use to find path thru intersection for each phase which has highest volume • Determine critical volume for each phase

  4. Desired Cycle Length • Cdes = L/(1-(Vc/(1615*PHF*(v/c)))) • 1615 vphg = sat flow assuming typical conditions of lane width, HV, Grade, parking, peds, buses, area type, lane util • L = total lost time per cycle • (v/c) = v/c ratio desired for critical volumes • Want to be between 0.85 – 0.95

  5. Splitting green • gTOT = C-L • gi = gTOT *(Vci/V) • Gi = gi -Yi +tLi • Do not do very short phases – confuse drivers

  6. Ped Signal Req’ts • Gp = 3.2 +(L/Sp) +2.7*(Nped/WE) • For WE > 10 ft • Gp = 3.2 +(L/Sp) +0.27*(Nped) • For WE <= 10 ft • L = length of crosswalk ft • Sp = average walking speed ft/s • Npeds = # of peds crossing per phase in a single crosswalk • WE = width of crosswalk • 3.2 = min start up time for peds

  7. Ped Signal Req’ts • WALKmin = 3.2 + 2.7(Nped/WE) • For WE > 10 ft • WALKmin = 3.2 + 0.27*Nped • For WE<= 10ft • Flashing Don’t walk = L/Sp • Gp <= G + Y • Either G +Y must be greater or a ped actuator must be provided

  8. Prob 21-5 • How many phases? • 3 EB L, EBT + WB TR, NB LTR • Critical Volumes • EW 730+100(1.32) = 862 or 1100 • 275(1.05) = 289 EBL • NB 900+45(1.05) +25(1.32) = 980 • Vc = 1100/2+289+980/3 = 1166

  9. Prob 21-5 • Cdes = L/(1-(Vc/(1615*PHF*(v/c)))) • L = 3*4 = 12 • Cdes = 12/(1-(1166/1615*.95*.9)) = 77.2s • Use 80 sec • gTOT = Cdes – L = 80 – 12 = 68sec • EBL g = 68*(289/1166) = 17s • EBT & WBTR g = 68*(550/1166) = 32s • NB g = 68 *(327/1166) = 19s

  10. Prob 21-5

  11. Prob 21-5 • Peds • WALKmin = 3.2 + 0.27*Nped • For WE<= 10ft • Flashing Don’t walk = L/Sp • EB, WB • WALKmin = 3.2 + 0.27*200/80 = 3.9s • Flashing Don’t walk = 36/3.2 = 11.3s • 32+4>?3.9+11.3 yes EW ok

  12. Prob 21-5 • Peds • WALKmin = 3.2 + 0.27*Nped • For WE<= 10ft • Flashing Don’t walk = L/Sp • NB • WALKmin = 3.2 + 0.27*200/80 = 3.9s • Flashing Don’t walk = 76/3.2 = 23.8s • 19+4>?3.9+23.8 no NB not ok

  13. Prob 21-5 • Retime signals to get same green ratio and satisfy ped needs • NB needs 28s G+Y => 24s green • To maintain ratio • EBL G = 24/19*17 = 22s • EBT &WBTR G = 24/19 * 32 = 40s • Cycle = 24+22+40+12 = 98s

More Related