Appendix D Traffic Impact Analysis - westplainseis.com

HCM Signalized Intersection Capacity Analysis
4: Hwy. 2 & Garfield St. 2/10/2011
Movement EBL EBT EBR WBL WBT WBR NBL NBT NBR SBL SBT SBR
Lane Configurations
Volume (vph) 148 2377 24 46 2476 266 60 29 118 215 23 118
Ideal Flow (vphpl) 1900 1900 1900 1900 1900 1900 1900 1900 1900 1900 1900 1900
Total Lost time (s) 5.5 5.5 5.5 5.5 5.5 5.0 5.0 5.0 5.0 5.0 5.0
Lane Util. Factor 1.00 0.91 1.00 0.91 1.00 1.00 1.00 1.00 1.00 1.00 1.00
Frt 1.00 1.00 1.00 1.00 0.85 1.00 1.00 0.85 1.00 1.00 0.85
Flt Protected 0.95 1.00 0.95 1.00 1.00 0.95 1.00 1.00 0.95 1.00 1.00
Satd. Flow (prot) 1787 5128 1787 5136 1599 1770 1863 1583 1805 1900 1615
Flt Permitted 0.05 1.00 0.05 1.00 1.00 0.74 1.00 1.00 0.74 1.00 1.00
Satd. Flow (perm) 88 5128 94 5136 1599 1380 1863 1583 1400 1900 1615
Peak-hour factor, PHF 0.93 0.93 0.93 0.93 0.93 0.93 0.93 0.93 0.93 0.93 0.93 0.93
Adj. Flow (vph) 159 2556 26 49 2662 286 65 31 127 231 25 127
RTOR Reduction (vph) 0 1 0 0 0 82 0 0 69 0 0 75
Lane Group Flow (vph) 159 2581 0 49 2662 204 65 31 58 231 25 52
Heavy Vehicles (%) 1% 1% 1% 1% 1% 1% 2% 2% 2% 0% 0% 0%
Turn Type pm+pt pm+pt Perm Perm Perm Perm Perm
Protected Phases 1 6 5 2 4 8
Permitted Phases 6 2 2 4 4 8 8
Actuated Green, G (s) 96.8 86.3 85.2 80.2 80.2 25.9 25.9 25.9 25.9 25.9 25.9
Effective Green, g (s) 96.8 86.3 85.2 80.2 80.2 25.9 25.9 25.9 25.9 25.9 25.9
Actuated g/C Ratio 0.73 0.65 0.64 0.60 0.60 0.19 0.19 0.19 0.19 0.19 0.19
Clearance Time (s) 5.5 5.5 5.5 5.5 5.5 5.0 5.0 5.0 5.0 5.0 5.0
Vehicle Extension (s) 3.0 3.0 3.0 3.1 3.1 3.0 3.0 3.0 3.0 3.0 3.0
Lane Grp Cap (vph) 206 3322 124 3092 963 268 362 308 272 369 314
v/s Ratio Prot c0.06 c0.50 0.01 c0.52 0.02 0.01
v/s Ratio Perm 0.50 0.24 0.13 0.05 0.04 c0.16 0.03
v/c Ratio 0.77 0.78 0.40 0.86 0.21 0.24 0.09 0.19 0.85 0.07 0.17
Uniform Delay, d1 41.0 16.6 17.1 21.9 12.1 45.4 43.9 44.9 51.8 43.8 44.7
Progression Factor 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00
Incremental Delay, d2 16.3 1.2 2.1 2.7 0.1 0.5 0.1 0.3 21.1 0.1 0.3
Delay (s) 57.3 17.8 19.2 24.6 12.2 45.8 44.1 45.1 72.9 43.9 44.9
Level of Service E B B C B D D D E D D
Approach Delay (s) 20.1 23.3 45.2 61.7
Approach LOS C C D E
Intersection Summary
HCM Average Control Delay 25.0 HCM Level of Service C
HCM Volume to Capacity ratio 0.90
Actuated Cycle Length (s) 133.2 Sum of lost time (s) 21.5
Intersection Capacity Utilization 88.0% ICU Level of Service E
Analysis Period (min) 15
Description: Southbound left turn lane, Optimized
Add EB & WB Auxilliary Lanes, connect turn bays from W. Center to S. Center
c Critical Lane Group
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