Benefits of Advanced Traffic Management Solutions: Before and After Crash Analysis for Deployment of a Variable Advisory Speed Limit System Alex Chambers California Polytechnic State University, San Luis Obispo July 13, 2016
Variable Advisory Speed Limit System Improve Safety
OR 217 Active Traffic Management Project Variable Advisory Speed Limit System Traveler Information System Adaptive Ramp Metering Queue Warning System Three Main Goals Improve Safety Reduce Congestion Utilize Existing Assets Objective: Evaluate the effectiveness of the Variable Advisory Speed Limit System in reducing crashes
28 overhead VSL signs 7 mainline Variable Message Signs (VMS) 6 arterial VMS 4 roadway weather sensors 5 radar traffic sensors 12 Bluetooth sensors 20 mainline dual loop stations
Crashes By Type 6% 9% 10% 4% 700 600 500 400 300 Crash Type By Injury Class n=1118 200 100 n=1118 Fixed Object Rear End Turning 71% Other Sideswipe - Overtaking 0 FATAL INJ A INJ B INJ C PDO Fixed Other Rear End Sideswipe - Overtake Turn
450 Rear End Collision Severity 400 350 300 250 200 150 100 50 0 Injury PDO n=797
WCCCA TOCS TDS VSL Activation 7/22/2011 7/23/2014 Incomplete Data, No PDO Incidents 12/31/2014 4/11/2016 12/31/2015 4/7/2016
Before 36 months After 21 months Traffic Accident Injury (TAI), Traffic Accident No Injury (TAN), and Traffic Accident Unknown Injury (TAU) are the primary sources used for analysis.
0.00% 5.00% 20.00% 15.00% 10.00% 0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8 2 2.2 2.4 2.6 2.8 3 3.2 3.4 3.6 3.8 4 4.2 4.4 4.6 4.8 5 5.2 5.4 5.6 5.8 6 6.2 6.4 6.6 6.8 7 7.2 7.4 Before After 0.00% 5.00% 10.00% 15.00% 20.00% 0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8 2 2.2 2.4 2.6 2.8 3 3.2 3.4 3.6 3.8 4 4.2 4.4 4.6 4.8 5 5.2 5.4 5.6 5.8 6 6.2 6.4 6.6 6.8 7 7.2 7.4 Before After
Similar crash trends to the WCCCA data Reduction around north terminus No large changes at VSL locations Milepost 0.00% 5.00% 10.00% 15.00% 20.00% 0 0.3 0.6 0.9 1.2 1.5 1.8 2.1 2.4 2.7 3 3.3 3.6 Before 3.9 4.2 After 4.5 4.8 5.1 5.4 5.7 6 6.3 6.6 6.9 7.2 7.5
140000 Official OR 217 Traffic Volumes 120000 Average Annual Daily Traffic 100000 80000 60000 40000 20000 0 2011 2012 2013 2014 0.5 1.21 2.16 2.73 3.32 4.02 4.57 5.6 6.3 6.96 Milepost
Portal provides a repository of traffic data for the entire Portland area.
1800000 SB Sanitized By Station 1600000 1400000 Number of Vehicles 1200000 1000000 800000 600000 400000 200000 0 7/1/2011 9/1/2011 11/1/2011 1/1/2012 3/1/2012 5/1/2012 7/1/2012 9/1/2012 11/1/2012 1/1/2013 3/1/2013 5/1/2013 7/1/2013 9/1/2013 Month 1037 1072 1073 1074 1075 1076 1077 1078 1079 1080 1111 1118 11/1/2013 1/1/2014 3/1/2014 5/1/2014 7/1/2014 9/1/2014 11/1/2014 1/1/2015 3/1/2015 5/1/2015 7/1/2015 9/1/2015 11/1/2015 1/1/2016 3/1/2016
1800000 SB Sanitized Average Traffic 1600000 1400000 Number of Vehicles 1200000 1000000 800000 600000 400000 200000 0 7/1/2011 9/1/2011 11/1/2011 1/1/2012 3/1/2012 5/1/2012 7/1/2012 9/1/2012 11/1/2012 1/1/2013 3/1/2013 5/1/2013 7/1/2013 9/1/2013 11/1/2013 1/1/2014 3/1/2014 5/1/2014 7/1/2014 9/1/2014 11/1/2014 1/1/2015 3/1/2015 5/1/2015 7/1/2015 9/1/2015 11/1/2015 1/1/2016 3/1/2016 Month
3000000 2500000 Monthly Traffic Volumes 2000000 1500000 1000000 500000 0 Before NB SB After
+ 20 % 2000 + 15 % 1500 + 10 % 1000 Change in Crashes + 05 % + 0 % - 05 % TAI TAN TAU Overall 500 0-500 Number of Crashes - 10 % - 15 % - 20 % Change in Crashes Number of Before Crashes Number of After Crashes n=2894-1000 -1500-2000
600 500 After Predicted After 400 300 200 100 0 TAI TAN TAU ABV ANM ASP ATL CRMN DUI HAZ HRN INFO MOA TRF
+ 20 % 1000 + 15 % 800 600 + 10 % 400 Change in Crashes + 05 % + 0 % - 05 % TAI TAN TAU Overall 200 0-200 Number of Crashes - 10 % - 15 % - 20 % Change in Crashes Number of Before Crashes Number of After Crashes n=1374-400 -600-800 -1000
+ 20 % 1000 + 15 % 800 600 + 10 % 400 Change in Crashes + 05 % + 0 % - 05 % TAI TAN TAU Overall 200 0-200 Number of Crashes -400-10 % Change in Crashes -600-15 % - 20 % Number of Before Crashes Number of After Crashes n=1465-800 -1000
+ 120 % 1200 + 100 % 1000 + 80 % 800 + 60 % 600 Change in Crashes + 40 % + 20 % 400 200 Number of Crashes + 0 % Clear Rain Snow 0-20 % Change in Crashes -200-40 % - 60 % Number of Before Crashes Number of After Crashes n=2894-400 -600
60 50 FIX OTHER REAR SS-O TURN 40 Crashes 30 20 10 0 7/1/2011 9/1/2011 11/1/2011 1/1/2012 3/1/2012 5/1/2012 7/1/2012 9/1/2012 11/1/2012 1/1/2013 3/1/2013 5/1/2013 7/1/2013 9/1/2013 11/1/2013 Month 1/1/2014 3/1/2014 5/1/2014 7/1/2014 9/1/2014 11/1/2014 1/1/2015 3/1/2015 5/1/2015 7/1/2015 9/1/2015
+ 30 % 1000 800 + 20 % 600 + 10 % 400 Change in Crashes + 0 % - 10 % DRY WET ICE SNO UNK 200 0-200 -400 Number of Crashes - 20 % Change in Crashes Number of Before Crashes -600-800 - 30 % Number of After Crashes n=1301-1000
+ 50 % 1000 + 40 % 800 + 30 % 600 + 20 % 400 Change in Crashes + 10 % + 0 % - 10 % DARK DAWN DAY DLIT UNK DUSK 200 0-200 Number of Crashes - 20 % -400-30 % Change in Crashes -600-40 % - 50 % Number of Before Crashes Number of After Crashes n=1301-800 -1000
+ 70 % Change in Crashes Number of Before Crashes 700 + 50 % Number of After Crashes 500 Change in Crashes + 30 % + 10 % 300 100 Number of Crashes - 10 % ANGL BACK FIX HEAD NCOL OTH PED REAR SS-M SS-O TURN -100-30 % n=1301-300
+ 30 % 800 + 20 % 600 Change in Crashes + 10 % + 0 % - 10 % - 20 % - 30 % FATAL INJ A INJ B INJ C PDO FATAL + INJ A Change in Crashes Number of Before Crashes Number of After Crashes n=1301 400 200 0-200 -400-600 -800 Number of Crashes
+ 70 % 400 + 50 % 300 + 30 % 200 Change in Crashes + 10 % - 10 % FATAL INJ A INJ B INJ C FATAL + INJ A 100 0-100 Number of Crashes - 30 % Change in Crashes -200-50 % Number of Before Crashes Number of After Crashes n=1450-300 - 70 % -400
+ 80 % 400 + 60 % 300 + 40 % 200 Change in Crashes + 20 % + 0 % - 20 % FATAL INJ A INJ B INJ C FATAL + INJ A 100 0-100 Number of Crashes - 40 % Change in Crashes -200-60 % Number of Before Crashes -300-80 % Number of After Crashes n=1450-400
Change 0% 2% 4% 6% 8% 10% 12% WCCCA WCCCA - NB WCCCA - SB TOCS TDS TDS - Rear End TDS - New Data TDS - New TDS - Rear Data End TDS TOCS WCCCA - SB WCCCA - NB WCCCA Change 6.04% 2.80% 3.13% 9.99% 4.43% 3.99% 4.21%
250 200 Site Selected Based on Short Term Trend Regression to the Mean Reduction Perceived effectiveness 150 Expected Average Crash Frequency 100 Reduction due to Treatment 50 0 2002 2004 2006 2008 2010 2012 2014 2016
Crashes 200 180 160 140 120 100 80 60 40 20 0 2000 2001 2002 2003 2004 Predicted Actual Expected
900 800 700 600 Crashes 500 400 300 200 100 0 F+I PDO Total Expected Actual
350 300 250 Crashes 200 150 100 50 0 Fatal and Injury Expected Actual
250 200 150 Crashes 100 50 0 Fatal and injury Expected Actual
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