Evaluation of NDDOT Fixed Automated Spray Technology (FAST) Systems November 4, 009 Shawn Birst, PE Program Director, ATAC Associate Research Fellow Upper Great Plains Transportation Institute North Dakota State University
Outline Introduction and Objectives System Description and Overview System Performance Case Studies Crash Data Analysis Benefit/Cost Summary
Introduction/Objectives Bridge decks are susceptible to frost and ice FAST systems can mitigate these conditions by automatically treating the road surface NDDOT has FAST systems (FreezeFree) I-9 Buxton Bridge I-94 Red River Bridge Objectives Describe how FAST systems work Discuss how the FAST systems perform Analyze benefit/cost for future installations
Winter Weather Conditions (Fargo) Month Total Precip. (in.) Total Snow Fall (in.) Number of Days Low Temp. 3º F September.3 0.0 (4.3%) October.9 0.7 3 (4.5%) November 0.9 7.5 7 (88.8%) December 0.7 8.6 3 (99.6%) January 0.7. 3 (99.9%) February 0.6 7. 8 (98.7%) March. 8.5 7 (86.7%) April.3.6 6 (53.7%) May.8 0.0 3 (9.%) Monthly (Oct-Apr).0 6.6 5 (8.%) Monthly (Oct-Mar).0 7. 6 (85.9%) Monthly (Nov-Mar) 0.8 8.6 9 (94.4%) Monthly (Nov-Apr) 0.9 7.6 7 (87.5%)
FAST System Components Pavement sensors Passive, provide: Pavement temperature & condition (dry or wet) If wet, freeze point estimation based on conductivity Active, provide: Pavement temperature & condition (dry or wet) If wet, freeze point determination by cooling a sample of the liquid on the road surface (Peltier element)
FAST System Components Weather sensors/environmental Sensing Station (ESS) Temperature and dew point Precipitation type and rate Wind speed Power/communication Pump system Pumps, plumbing, and spray nozzles Storage tank with anti-icing chemical Power/communication Computer controller
FAST Systems Operation Remote processing unit (RPU) at the ESS receives Pavement temp. and freeze pt. data (pavement sensors) Atmospheric information from the ESS Spray algorithms for various conditions Frost: pavement temp., dew point Freeze: pavement temp., liquid freeze point Precipitation: pavement temp., rate of precip. If conditions are met and wind speed is less than threshold: The ESS RPU sends spray command to the FAST RPU The FAST system cycles through the spray nozzles Pumps re-pressurize the system after spray cycle
Spray Algorithms
Buxton Bridge FAST Overview Bridge Near Buxton, ND on I-9 Two structures, 330 ft ea. Two lanes per direction ADT of ~K (007) FAST system Installed in 00, operational December Total cost ESS = $68,000 Treats 370 ft (bridge + 40 ft of roadway) per bridge 0 spray nozzles (0 for each direction)
Buxton Bridge FAST System
Red River Bridge FAST - Overview Bridge Spans Red River on I-94 Single structure,,300 ft Three lanes per direction ADT of ~63K (007) FAST system Installed in 005 with Mn/DOT, operational Jan 006 Total cost ESS = $650,575 (NDDOT) Treats,300 ft of bridge deck + (00 ft roadway ND, 800 ft roadway MN) Spray nozzles: 30 ND and 4 MN Dual closed-loop system
Red River Bridge FAST System
Buxton Bridge Level of Use Winter 007 FAST Applications Spray Application Event Frequency Days with Spray Applications 0 Days with Frost and Freeze Conditions 4 Total Sprays 0 Manual Sprays Failed Sprays 6 Winter 007 Application by Condition Spray Condition # of Days Total Sprays Sprays/ Day Frost 64 99.5 Freeze 6 0.8 Number of Sprays/Day 3 4 5 38 (59%) 35 (56%) 8 (8%) 4 (3%) 7 (%) 6 (0%) (%) 6 (0%) - (%)
Red River Bridge Level of Use Winter 007 FAST Applications Spray Application Event Frequency Days with Spray Applications 67 Days with Frost and Freeze Conditions 3 Days with Frost and Precipitation Conditions 9 Days with Freeze and Precipitation Conditions Days with Frost, Freeze and Precipitation Conditions 7 Total Sprays 69 Manual Sprays 4 Failed Sprays 8 Winter 007 FAST Application by Condition Spray Condition # of Days Total Sprays Sprays/ Day Frost 64 7.0 Freeze 38 88.3 Precipitation 5 50 3.3 Number of Sprays / Day 3 4 5 6 7 8 9 0 4 5 0 (38%) (39%) (6%) 9 6 4 (50%) (6%) (%) 7 4 (47%) (7%) (3%) 5 (3%) 3 (5%) (5%) - - - - - - (3%) - - - - - (3%) (3%) - - (7%) (7%)
Frost Event: Buxton Bridge
Frost Event: Buxton Bridge Date Time (CST) 04/05/09 3:43 04/05/09 3:58 04/06/09 0:8 04/06/09 06:8 04/06/09 06:34 Status Atmospheric Conditions Surface Temp Dew Point Wind Speed Inactive - critical conditions not detected 3.7F.9F 9 mph Sprayer not activated since the wind speed of 7 mph exceeds the maximum wind speed threshold of 5 mph. Sprayer activated due to a frost condition. The surface temperature of.0f is within.8 or lower of the dew point of.3f. 3.F.8F 7 mph.0f.3f 4 mph Inactive due to frost hold off time 9.4F.7F 5 mph Sprayer activated due to a frost condition. The surface temperature of 9.4F is within.8 or lower of the dew point of.6f. 9.4F.6F 4 mph Scan Web Data: Buxton Bridge Frost Event (8:00 am, 4/5/009 to 8:00 am, 4/6/009)
Rain/ Snow Event: Red River Bridge
Rain/Snow Event: Red River Bridge Date Time (CST) 0/08-08:3 0/08-7:53 0/08 - :55 Status Sprayer activated due to a frost condition. The surface temperature of.f is within.8 or lower of the dew point of.6f. Sprayer activated due to a frost condition. The surface temperature of 8.8F is within.8 or lower of the dew point of 7.F. Sprayer activated due to a frost condition. The surface temperature of 9.3F is within.8 or lower of the dew point of 30.4F. Atmospheric Conditions Surface Temp Dew Point Precip Wind Speed.F.6F None 4 mph 8.8F 7.F None 6 mph 9.3F 30.4F None 4 mph 0/09-00:07 Active due to rain and wet surface conditions 3.5F 3.4F Rain 4 mph 0/09-0:30 Active due to rain and wet surface conditions 3.3F 3.F Rain Calm 0/09-04:8 Active due to rain and wet surface conditions 3.5F 33.4F Rain 5 mph 0/09-05:30 Active due to rain and wet surface conditions 3.7F 34.0F Rain 4 mph 0/ - 04:43 Sprayer activated due to a frost condition. The surface temperature of 3.9F is within.8 or lower of the dew point of 3.5F. 3.9F 3.5F Unid 6 mph 0/ - 07:39 Active due to rain and wet surface conditions 3.7F 3.5F Unid Calm 0/ - 8:3 Active due to rain and wet surface conditions 3.5F 6.8F Unid 6 mph 0/ - :08 Active due to rain and wet surface conditions 7.3F 5.F Unid 6 mph 0/ - : Active due to rain and wet surface conditions 7.F 5.0F Unid 4 mph 0/ - 3:6 Active due to rain and wet surface conditions 6.F 4.6F Unid 4 mph 0/ - 00:9 Active due to rain and wet surface conditions 4.8F 3.7F Unid 5 mph 0/ - 03:4 Active due to rain and wet surface conditions 4.4F 0.8F Unid 4 mph Scan Web Data: Red River Bridge - Feb 7, 009 (noon) to Feb 3, 009 (noon)
Fargo District Perspectives ~95% reliable (communication problems) Perform well for frost and freeze conditions Vendor support is important initially System limitations: system will not spray when Wind speed is greater than 5 mph Surface temperature is below o F Anti-icing chemical (CF7) performs well Deicing/anti-icing properties Minimal environmental impacts Non-corrosive properties
Crash Analysis Crash data from the NDDOT and Mn/DOT October 996 June 008 ( winters) Filtered crash data Removed deer/debris, catch on fire, tire failure, nonwinter, etc. Buxton Bridge 6.5 winter seasons before and 5.5 after Red River Bridge 9.5 winter seasons before and.5 after
Buxton Bridge Crashes 0 9 8 I-9 Buxton Bridge Winter Season Crash Summary Injury 4 Propery Damage Number of Crashes 7 6 5 4 3 0 7 6 6 6 5 4 3 3 0 996 997 998 999 000 00 00 003 004 005 006 007 Winter Season
Buxton Bridge Crashes Buxton Bridge Crash Data Crash Scenario Winter Seasons Total Crashes Total Crashes PD Crashes Injury Crashes Before FAST 6.5 40 6. 4.8. After FAST 5.5 4.5. 0.4 Change in Crashes with FAST -59% -54% -70% Buxton Bridge Crash Data Normalized for AADT Crash Scenario Before FAST AADT/Crash Scenario Annual Traffic Volume Total Crashes/ Annual Volume x 0 6 Property Crashes/ Annual Volume x 0 6 Injury Crashes/Annual Volume x 0 6 9,93 3,39,965.8.4 0.36 After FAST,77 4,079,686 0.6 0.53 0.09 Change in Crashes with FAST -66% -6% -75%
Red River Bridge Crashes ND 0 I-94 Red River Bridge Winter Season Crash Summary (North Dakota) Injury Property Damage Number of Crashes 8 6 4 0 9 9 8 6 5 4 4 3 996 997 998 999 000 00 00 003 004 005 006 007 Winter Season
Red River Bridge Crashes ND Red River Bridge Crash Data ND Crash Scenario Winter Seasons Total Crashes Total Crashes PD Crashes Injury Crashes Before FAST 9.5 58 6. 4.8.3 After FAST.5 8 3. 3. 0.0 Change in Crashes with FAST -48% -34% -00% Red River Bridge Crash Data Normalized for AADT ND Crash Scenario AADT/Crash Scenario Annual Traffic Volume Total Crashes/ Annual Volume x 0 6 PD Crashes/ Annual Volume x 0 6 Injury Crashes/ Annual Volume x 0 6 Before FAST 53,50 9,534,800 0.3 0.5 0.06 After FAST 6,37,745,705 0.4 0.4 0.00 Change in Crashes with FAST -55% -43% -00%
Red River Bridge Crashes MN Number of Crashes 4 0 8 6 4 7 I-94 Red River Bridge Winter Season Crash Summary (Minnesota) Non-Incapacitating Injury Possible Injury Property Damage 0 6 5 4 4 4 3 3 0 996 997 998 999 000 00 00 003 004 005 006 007 Winter Season
Red River Bridge Crashes MN Red River Bridge Crash Data MN Crash Scenario Winter Seasons Total Crashes Total Crashes PD Crashes Poss. Inj. Crashes Before FAST 9.5 5 5.7 4.4 0.6 After FAST.5 9* 3.6.4 0.8 Change in Crashes with FAST -37% -46% 7% * Removed property damage and possible injury crashes Red River Bridge Crash Data Normalized for AADT MN Crash Scenario AADT/Crash Scenario Annual Traffic Volume Total Crashes/ Volume x 0 6 Property Damage/ Volume x 0 6 Possible Injury/ Volume x 0 6 Before FAST 53,50 9,534,800 0.9 0.3 0.03 After FAST 6,37,745,705 0.6 0. 0.035 Change in Crashes with FAST -46% -53% 9%
Red River Bridge Crashes (ND & MN Combined) Red River Bridge Total Crash Data Crash Scenario AADT/Crash Scenario Annual Traffic Volume Total Crashes/Year Total Crashes/ Annual Volume x 0 6 Before FAST 53,50 9,534,800.79 0.60 After FAST 6,37,745,705 6.80* 0.30 Change in Crashes with FAST -4% -50% * Removed property damage and possible injury crashes
Benefit/Cost of FAST Systems System Benefits Quantitative Societal costs of crashes (life, productivity, legal, property damage) Maintenance costs (staff, equipment, material) Qualitative Reassurance and peace of mind System Costs Installation Maintenance and operations
Buxton Bridge FAST B/C Crash Reductions Crash-Vehicle Data (Factored for AADT) Crash Scenario Winter Seasons Total Crash - Veh. Crash-Veh. Property Damage Crash Veh. Injury Crash Veh. Before FAST 6.5 49 7.5 5.8.7 After FAST 5.5..8 0.3 Change in Crash-Vehicles w/ FAST -7% (5.4) -69% (4.0) -8% (.4) Reduced Manual Applications Winter 007 Spray Occurrences by Condition Spray Condition Sprays During Normal Hours Sprays Outside of Normal Hours Frost % 79% Freeze 6% 74%
Buxton Bridge FAST B/C System Benefits Crash reduction: $78,735/year Manual treatment reduction: $3,860/year System Costs Installation: $68,53 (00 Dollars) Maintenance: $,000/year (plus pump replacements of $5,000 at year 7 and 4) Utilities: $,6/year Chemical: $9,47/year (,55 gal at $8./gal) Benefit-Cost Analysis (0 yr. period) 4.3 (net benefits of $,57,869)
Red River Bridge FAST B/C Crash Reductions Crash-Vehicle Data (Factored for AADT) Crash Scenario Winter Seasons Total Crash-Veh. Crash Veh. Prop. Damage Crash Veh. Injury Crash Veh. Poss. Inj. Crash Veh. Before FAST 9.5 68 7.7.9.7.0 After FAST.5 4 9.6 8.6 0.3 0.7 Change in Crash-Vehicles w/ FAST -46% (8.) -34% (4.3) -87% (.4) -66% (.3) Reduced Manual Applications Winter 007 Spray Occurrences by Condition Spray Condition Sprays During Normal Hours Sprays Outside of Normal Hours Frost 0% 80% Freeze 40% 60%
Red River Bridge FAST B/C System Benefits Crash reduction: $6,578/year Manual treatment reduction: $48,983/year Traffic congestion savings: $4,060/year System Costs Installation: $,30,000 (005 Dollars) Maintenance: $,000/year (plus pump replacements of $0,000 at year 7 and 4) Utilities: $,955/year Chemical: $66,703/year (8,35 gal At $8.0/gal) Benefit-Cost Analysis (0 yr. period).3 (net benefits of $675,84)
Summary NDDOT Fargo District FAST work well High level of use (007) Buxton (0 days spraying 0 times) Red River (67 days spraying 0 times) System limitations are evident Wind speed >5 mph (no spray) and/or Pavement temp. < o F (no spray) Steep learning curve with new systems Vendor assistance is important
Summary Buxton Bridge FAST Total crash reduction of 66% B/C of 4.3 with a net benefit of $,57,869 Red River Bridge FAST Combined total crash reductions of 50% B/C of.3 with a net benefit of $675,84
Questions http://www.ugpti.org/pubs/pdf/dp9.pdf