Minnesota Local Road Research Board Local Operational Research Assistance Program (OPERA) June 18, 2012 Evaluation of De-Icing and Anti-Icing Technologies OPERA Project Number: 2010-2 Project Sponsor: City of Grand Rapids, Minnesota Report Authors: Tom Pagel, P.E. (1), Jeffrey Davies (2), Glen D. Hodgson, P.E (3) (1) Grand Rapids City Engineer (phone 218-326-7626); (2) Grand Rapids Public Works Director and project leader (phone: 218-326-7480); (3) Engineering Instructor and Principal Report Author, Itasca Community College (phone 218-322-2391)
Research Problem De-icing and anti-icing of public roadways is an annual challenge for local road agencies. In light of increasing environmental concerns and decreasing budgets, it is imperative that local agencies utilize methodologies that minimize chemical usage and decrease operational costs while maintaining levels of service expected by the traveling public. The City of Grand Rapids, MN is one such local agency. Figure 1 shows the location of Grand Rapids within the State of Minnesota. Problem Solution The City of Grand Rapids actively investigates and implements alternative technologies and procedures for de-icing and anti-icing that may have potential to improve winter roadway maintenance while still saving operating costs. For many years the City has utilized standard tailgate spreader technology to apply de-icing and anti-icing materials. In the recent past the City has also purchased an Epoke bulk spreader (model: Sirius Combi II.) The purpose of this research project was to compare the operational efficacy of these two technologies. Research Procedure Three evaluation criteria were originally identified for study and comparison between the two technologies: material usage, operational efficiency (time to complete a snow-removal route), and roadway condition after de-icing. To facilitate such comparisons two equivalent snow removal/de-icing routes were identified. Maps showing the two routes and other route data are included in Appendix A. When a deicing event occurred (as determined by the Public Works Director) the Epoke and tailgate spreaders were each randomly assigned to one of the routes. Equipment operators recorded the amount of material used on each route as well as the time required to complete the routes. After the snow removal and de-icing operations were completed a pair of observers (ICC Engineering students) drove each route and numerically rated the condition of the roadway. These observers did not have knowledge of which technology was used on which route. The rating system used is included in Appendix B. Each of the individual segments in the routes was rated using this system. These raw scores were then reduced to an overall average rating for each route.
Figure 1 Location Map for City of Grand Rapids, MN
Results Material Usage Table 1 below shows the data collected for material (salt and liquid magnesium chloride) used by the two types of technologies. Both the Epoke and the tailgate spreader applied salt to the roadway. Only the Epoke had the option of applying magnesium chloride. The data appear to show that the Epoke used more material, but the p-value of 0.20 does not suggest that the difference in the usages is statistically significant. Therefore, no conclusions should be drawn regarding material usage differences between the two technologies Results Operational Efficiency Table 2 below shows the data collected for the tailgate spreader and the Epoke to complete the routes assignments for each event. The data could be interpreted to suggest that the tailgate spreader is more efficient at completing a de-icing route. However, another plausible explanation is that the Epoke spreader serviced Route B much more often than did the tailgate spreader. The data could simply be suggesting that Route B generally takes somewhat longer to complete. (Note that during event 5 the Epoke finished Route A slightly faster than the tailgate spreader completed Route B.) Therefore, no conclusions should be drawn regarding differences in operational efficiencies of the two technologies. Results Roadway Condition Ratings Table 3 below shows the data collected for roadway conditions after treatment of the various route assignments by the two types of spreaders. The very high p-value for the difference in ratings indicates that there was no significant difference in how well each technology de-iced the snow removal routes.
TABLE 1--MATERIAL USAGE DATA TABULATION Additional DATA SUMMARY Epoke Salt Tailgate Spreader Data Epoke Data Event # Date Salt Snowfall (in) Route (lbs) MgCl (gal) Salt Route (lbs) MgCl (gal) 1 1/29/2011 3.0 A 1540 0 B 3254 57 1714 1A 1/31/2011 0.8 A 1560 0 B 3135 55 1575 1B 2/3/2011 N/A A 1460 0 B 2998 53 1538 2 2/23/2011 3.0 A 660 0 B 3368 58 2708 2A 2/24/2011 1.0 A 1200 0 B 3272 57 2072 3 1/23/2012 2.0 B 1420 0 A 2520 0 1100 3A 1/24/2012 <1.0 B 2840 0 A 3570 63 730 4 1/28/2012 2.7 A 6060 0 B 1860 0-4200 5 2/21/2012 2.5 B 2220 0 A 2320 41 100 6 2/26/2012 8.0 A 460 0 B 530 9 70 6A 2/27/2012 0.0 A 1080 0 B 1930 35 850 Mean 751 N 11 Std Dev 1826 Std Error 550 T-stat 1.36 D.F. 10 p 0.20
TABLE 2--OPERATIONAL EFFICIENCY TABULATION Additional DATA SUMMARY Epoke Time Tailgate Spreader Data Epoke Data Event # Date Snowfall (in) Route Hours Route Hours 1 1/29/2011 3.0 A 1.05 B 1.30 0.25 1A 1/31/2011 0.8 A 0.75 B 0.95 0.20 1B 2/3/2011 N/A A 1.30 B 1.50 0.20 2 2/23/2011 3.0 A 0.75 B 1.50 0.75 2A 2/24/2011 1.0 A 0.68 B 1.00 0.32 3 1/23/2012 2.0 B 0.97 A 1.00 0.03 3A 1/24/2012 <1.0 B 1.07 A 1.27 0.20 4 1/28/2012 2.7 A 0.92 B 0.75-0.17 5 2/21/2012 2.5 B 1.25 A 1.10-0.15 6 2/26/2012 8.0 A 0.97 B 1.50 0.53 6A 2/27/2012 0.0 A 0.80 B 1.00 0.20 Mean 0.215 N 11 Std Dev 0.267 Std Error 0.081 T-stat 2.66 D.F. 10 p 0.02
TABLE 3--ROADWAY CONDITION RATINGS TABULATION Epoke DATA SUMMARY Rating Increase Tailgate Spreader Data Epoke Data Event # Date Snowfall (in) Route Condition Rating Route Condition Rating 1 1/29/2011 3.0 A 4.67 B 5.08 0.41 1/30/2011 4.44 5.90 1.46 1A 1/31/2011 0.8 A 5.00 B 4.37-0.63 2/1/2011 5.25 5.76 0.51 1B 2/3/2011 N/A A 5.38 B 6.28 0.90 2/4/2011 5.79 5.46-0.33 2/5/2011 7.21 6.20-1.01 2 2/23/2011 3.0 A 5.79 B 4.24-1.55 2A 2/24/2011 1.0 A 7.08 B 7.06-0.02 2/24/2011 8.92 9.80 0.88 2/25/2011 9.60 9.76 0.16 3 1/23/2012 2 B 3.91 A 3.46-0.45 3A 1/24/2012 <1.0 B 7.41 A 8.33 0.92 4 1/28/2012 2.7 A 7.02 B 6.43-0.59 1/29/2012 8.27 7.72-0.55 5 2/21/2012 5 B 8.20 A 9.75 1.55 2/22/2012 8.57 9.62 1.05 6 2/26/2012 8 A 7.19 B 7.00-0.19 6A 2/27/2012 0 A 9.83 B 9.89 0.06 Mean 0.14 N 19 Std Dev 0.85 Std Error 0.19 T-stat 0.70 D.F. 18 p 0.49
Implementation It appears that neither the Epoke technology nor the tailgate spreader technology had any advantage on the two snow removal/de-icing routes. It should be noted that both routes were in residential areas of the City of Grand Rapids. Normal operating procedure of the Public Works Department is to assign the Epoke to more heavily traveled roadways in the City. It appears that this procedure is sound and should be continued. Status The initial research project is complete. Unfortunately, no significant conclusions can be drawn as a result of the research. Additional research could lead to more meaningful conclusions. Additional research might include: Comparing the two technologies on non-residential streets Comparing the two technologies on longer test routes Comparing the two technologies for a longer time period (e.g., years with more snow events.) Project Duration Approval of this OPERA research project was transmitted to the City of Grand Rapids by the OPERA Program Coordinator on November 2, 2010. Data collection began in January of 2011. The remainder of the 2010-2011 winter produced very few snow events. The project team then requested an extension of the project time table through the winter of 2011-2012. An Interim Report dated June 8, 2011, and describing the request and justification for a time extension was transmitted to the OPERA Program Coordinator. The Coordinator approved that report in June, 2011. Project End Date The research portion of the project ended on June 15, 2012. Upon the request of the OPERA program, presentation of research results may occur in the future at one or more professional conferences. Project Costs Total project cost through final report preparation was approximately $8,000. OPERA funds used for the project totaled $4,000. The remaining project funding was provided by the City of Grand Rapids and Itasca Community College through a grant from the Blandin Foundation.
APPENDICES
APPENDIX A Route Maps and Segment Listings
City of Grand Rapids De-Icing Study Route A Segments Nominal # Street Start End Length A-1 SE 17th St SE 7th Ave 150' west 150 A-2 SE 17th St. End of A-1 750' west 750 A-3 SE 17th St. End of A-2 750' west 750 A-4 SE 17th St. End of A-3 150' east of Pokegama 750 A-5 SE 17th St. 150' east of Pokegama Pokegama Ave 150 A-6 SE 21st St. SE 7th Ave 150' west 150 A-7 SE 21st St. End of A-6 750' west 750 A-8 SE 21st St. End of A-7 750' west 750 A-9 SE 21st St. End of A-8 150' east of Pokegama 750 A-10 SE 21st St. 150' east of Pokegama Pokegama Ave 150 A-11 SW 21st St. Pokegama Ave 150' west of Pokegama 150 A-12 SW 21st St. 150' west of Pokegama SW 3rd Ave 600 A-13 SW 21st St. SW 3rd Ave SW 3rd Ave 550 A-14 SW 3rd Ave SW 21st St. Timberline Circle 825 A-15 Timberline Circle SW 3rd Ave Timberline Drive 475 A-16 Timberline Circle Timberline Drive End of Circle 500 A-17 SW 3rd Ave SW 21st St. 150' north 150 A-18 SW 3rd Ave End of A-17 900' north 900 A-19 SW 3rd Ave End of A-18 150' south of 15th St. 900 A-20 SW 3rd Ave 150' south of 15th St. SW 15th St. 150 A-21 Fraser Drive SW 15th St. 150' south of 15th St. 150 A-22 Fraser Drive 150' south of 15th St. 900' south 900 A-23 Fraser Drive End of A-22 150' north of 21st St. 900 A-24 Fraser Drive 150' north of 21st St. SW 21st St. 150 Nominal Total Length (feet) 12400
City of Grand Rapids De-Icing Study Route B Segments Nominal # Street Start End Length B-1 SE 13th St 7th Ave SE 150' west of 7th Ave 150 B-2 SE 13th St End of B-1 750' west 750 B-3 SE 13th St End of B-2 750' west 750 B-4 SE 13th St End of B-3 150' east of Pokegama 750 B-5 SE 13th St 150' east of Pokegama Pokegama Ave 150 B-6 SW 13th St Pokegama Ave 150' west of Pokegama 150 B-7 SW 13th St 150' west of Pokegama 150' east of Fraser Dr 475 B-8 SW 13th St 150' east of Fraser Dr Fraser Drive 150 B-9 Fraser Dr SW 13th St 575' north 575 B-10 Fraser Dr End of B-9 150' south of SW 10th St 575 B-11 Fraser Dr 150' south of SW 10th St SW 10th St 150 B-12 SW 1st Ave SW 13th St 150' south of SW 13th St 150 B-13 SW 1st Ave 150' south of SW 13th St SW 15th St 500 B-14 Fraser Dr SW 13th St 150' north of SW 15th St 500 B-15 Fraser Dr 150' north of SW 15th St SW 15th St 150 B-16 SW 15th St SW 1st Ave 150' west of SW 1st Ave 150 B-17 SW 15th St 150' west if SW 1st Ave 625' west 625 B-18 SW 15th St End of B-17 Forest Hills Av e 625 B-19 Forest Hills Ave SW 15th St Valley Circle 725 B-20 Valley Circle Forest Hills Ave End of Valley Circle 225 B-21 Pinewood Circle Forest Hills Ave End of Pinewood Circle 375 B-22 Timber Ridge Lane Forest Hills Ave 650' west 650 B-23 Timber Ridge Lane End of B-20 End of Timber Ridge Lane 650 B-24 Forest Hills Ave SW 15th St End of Forest Hills Ave 875 B-25 Donovan Lane Forest Hills Ave 575' north 575 B-26 Donovan Lane End of B-23 150' south of SW 10th St 575 B-27 Donovan Lane 150' south of SW 10th St SW 10th St 150 Nominal Total Length 12125
APPENDIX B Roadway Condition Rating System City of Grand Rapids De-Icing Study Street Condition Rating System Rating Description 0 Impassable 2 Nearly 100% icy; travel is hazardous; safe and comfortable speed is more than 15 mph below normal travel speeds 4 50% or more of street segment is slippery; travel is difficult and slow; safe and comfortable speed is 5 to 15 mph below normal travel speeds 6 Approximately 25% of the street segment is slippery; safe and comfortable travel speed is within 5 mph of normal travel speeds 8 A few (approximately 10%) slippery spots that are easily avoided; able to maintain normal travel speeds 10 Completely clear pavement