Lane Volume Allocation Reality No single lane all

Lane Volume Allocation

Reality! No single lane all through traffic Slide 2

What to do? w Distribute volume among lanes to n n n Identify lane utilization Determine need for lane adjustment Estimate critical lane volumes w Lane volume allocation Slide 3

Lane Volume Allocation Rules w All turning movements are placed in exclusive left or right turn lanes, if present w Through traffic is distributed evenly among through lanes w Right turns are equivalent to through movements, if no right turn lanes exist w Shared left and through lane requires special procedure Slide 4

Lane Allocation Example 1 Slide 5

150 Lane Allocation Example 1 175 Left turns in exclusive turn lanes 180 250 Slide 6

150 Lane Allocation Example 1 175 Right turns in exclusive turn lanes 250 320 180 Slide 7

150 Lane Allocation Example 1 175 Through in single through only lanes 320 180 500 250 650 180 Slide 8

550 150 550 Lane Allocation Example 1 585 175 250 650 180 Through and right in shared lanes 320 180 500 WB (1020+150)/2 = 585 SB (850+250)/2 = 550 Slide 9

Lane Allocation Example 2 Slide 10

Through Vehicle Equivalents for Left Turns Opposing Volume Through+Right (vph) Through Vehicle Equivalents 0 -199 1. 1 200 -599 2. 0 600 -799 3. 0 800 -999 4. 0 >1000 5. 0 Slide 11

180 Shared through & left lanes 413 WB 1. Opposing traffic to LT EB TH+RT = 650+70=720 2. 1 LT =3 TH 3. Total equivalent TH 500+3(75)+100 = 825 4. Per lane 825/2 = 412. 5 350 200 412 160 350 450 Lane Allocation Example 2 Slide 12

180 Shared through & left lanes 413 EB 1. Opposing traffic to LT WB TH+RT=500+100=600 350 200 412 160 350 450 Lane Allocation Example 2 Slide 13

Through Vehicle Equivalents for Left Turns Opposing Volume Through+Right (vph) Through Vehicle Equivalents 0 -199 1. 1 200 -599 2. 0 600 -799 3. 0 800 -999 4. 0 >1000 5. 0 Slide 14

180 450 Lane Allocation Example 2 Shared through & left lanes 413 412 540 350 200 160 350 540 EB 1. Opposing traffic to LT WBTH+RT=500+100=600 2. 1 LT =3 TH 3. Total equivalent TH 650+3(120)+70 = 1080 4. Per lane 1080/2 = 540 Slide 15

180 450 Lane Allocation Example 2 How many TH in shared lane? 413 412 540 EB 540 - 3(120) = 180 vph WB 412 - 3(75) = 187 vph 350 200 160 350 540 Slide 16

Example 3 Tophat: What are WB lane volumes? Slide 17

Example 3 Answer Slide 18

Example 3 Tophat: What are EB lane volumes? Slide 19

Example 3 Answer Slide 20

Extra Reading w Signal Timing Class Notes n See supplemental reading on Course Website section 5. 3 Slide 21