Appendix D Traffic Impact Analysis - westplainseis.com

HCM Signalized Intersection Capacity Analysis
3: Hwy. 2 & Lawson St 2/14/2011
Movement EBL EBT EBR WBL WBT WBR NBL NBT NBR SBL SBT SBR
Lane Configurations
Volume (vph) 84 2343 37 113 1743 63 93 54 114 108 47 61
Ideal Flow (vphpl) 1900 1900 1900 1900 1900 1900 1900 1900 1900 1900 1900 1900
Total Lost time (s) 5.0 5.0 5.0 5.0 5.0 5.0 4.0 4.0 4.0 4.0
Lane Util. Factor 1.00 0.95 1.00 1.00 0.95 1.00 1.00 1.00 1.00 1.00
Frt 1.00 1.00 0.85 1.00 1.00 0.85 1.00 0.90 1.00 0.92
Flt Protected 0.95 1.00 1.00 0.95 1.00 1.00 0.95 1.00 0.95 1.00
Satd. Flow (prot) 1787 3574 1599 1787 3574 1599 1787 1689 1787 1722
Flt Permitted 0.05 1.00 1.00 0.05 1.00 1.00 0.57 1.00 0.40 1.00
Satd. Flow (perm) 91 3574 1599 91 3574 1599 1075 1689 758 1722
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) 90 2519 40 122 1874 68 100 58 123 116 51 66
RTOR Reduction (vph) 0 0 6 0 0 14 0 55 0 0 37 0
Lane Group Flow (vph) 90 2519 34 122 1874 54 100 126 0 116 80 0
Heavy Vehicles (%) 1% 1% 1% 1% 1% 1% 1% 1% 1% 1% 1% 1%
Turn Type pm+pt Perm pm+pt Perm Perm Perm
Protected Phases 1 6 5 2 4 8
Permitted Phases 6 6 2 2 4 8
Actuated Green, G (s) 88.3 88.3 88.3 87.3 87.3 87.3 21.4 21.4 21.4 21.4
Effective Green, g (s) 88.3 88.3 88.3 87.3 87.3 87.3 21.4 21.4 21.4 21.4
Actuated g/C Ratio 0.69 0.69 0.69 0.68 0.68 0.68 0.17 0.17 0.17 0.17
Clearance Time (s) 5.0 5.0 5.0 5.0 5.0 5.0 4.0 4.0 4.0 4.0
Vehicle Extension (s) 3.0 3.8 3.8 3.0 2.5 2.5 3.0 3.0 3.0 3.0
Lane Grp Cap (vph) 142 2452 1097 128 2424 1085 179 281 126 286
v/s Ratio Prot 0.03 c0.70 0.04 c0.52 0.07 0.05
v/s Ratio Perm 0.40 0.02 0.61 0.03 0.09 c0.15
v/c Ratio 0.63 1.03 0.03 0.95 0.77 0.05 0.56 0.45 0.92 0.28
Uniform Delay, d1 22.6 20.2 6.5 58.2 14.0 6.9 49.3 48.3 52.8 46.9
Progression Factor 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00
Incremental Delay, d2 8.9 25.6 0.0 64.7 1.5 0.0 3.7 1.1 56.2 0.5
Delay (s) 31.5 45.8 6.5 122.8 15.5 6.9 53.1 49.5 109.0 47.5
Level of Service C D A F B A D D F D
Approach Delay (s) 44.7 21.6 50.7 78.1
Approach LOS D C D E
Intersection Summary
HCM Average Control Delay 37.4 HCM Level of Service D
HCM Volume to Capacity ratio 0.97
Actuated Cycle Length (s) 128.7 Sum of lost time (s) 9.0
Intersection Capacity Utilization 101.9% ICU Level of Service G
Analysis Period (min) 15
Description: Optimized
Add EB/WB Rt Turn Bays, Reconfigure N/S approaches
c Critical Lane Group
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