Download presentation
Presentation is loading. Please wait.
Published byAllen McKenzie Modified over 8 years ago
1
Roadtech 10/23/2013 Snow and Ice Operations 2013 Focus on Efficiency !
2
Roadtech 10/23/2013 Agenda Today ● Operational Advantages to being Proactive (Anti-Icing) ● Tools to Achieve Performance ● Where is Snow and Ice Heading ● Chemicals Options and how best to use them ● Why, we do the things we do!
3
Roadtech 10/23/2013 Weather Impacts on Safety Road Weather ConditionsCrashesInjuriesFatalities Wet Pavement1,128,000507,9005,500 Rain707,000330,2003,300 Snow/Sleet225,00070,900870 Icy Pavement190,10062,700680 Snow/Slushy Pavement 168,30047,700620 Fog 38,00015,600600 Total Attributable to Weather* 1,511,200629,3007,130 *The sum of the crashes under each road weather condition does not equal the total number attributable to weather; crashes may be double counted, e.g. wet pavement and rain. Source: http://www.ops.fhwa.dot.gov/weather/q1_roadimpact.htm Annual average from 1995- 2008
4
Roadtech 10/23/2013 Weather Impacts on Mobility Weather Conditions Freeway Traffic Flow Reductions Average Speed VolumeCapacity Light Rain/Snow3% - 13%5% - 10%4% - 11% Heavy Rain3% - 16%14%10% - 30% Heavy Snow5% - 40%30% - 44% 12% - 27% Low Visibility10% - 12%-12% Source: http://www.ops.fhwa.dot.gov/weather/q1_roadimpact.htm ● On signalized arterial routes, speed reductions can range from 10% - 25% on wet pavement and from 30% - 40% with snowy or slushy pavement
5
Roadtech 10/23/2013 Weather Impacts on Productivity Adverse weather can increase operating and maintenance costs of: ● Each year CVOs lose an estimated $32.6B vehicle hours due to weather-related congestion in 281 of nation's metropolitan areas ● Estimated cost of weather- related delay to trucking companies ranges from $2.2B to $3.5B annually Source: http://www.ops.fhwa.dot.gov/weather/q1_roadimpact.htm
6
Roadtech 10/23/2013 Snow and Ice Removal This is the most important operation done by Highway Departments, effects the most and observed by everyone.
7
Roadtech 10/23/2013 Winter Operations ● Professionalism ▶ Respect (Customers and Operators) ▶ Documentation (Written Policy) Establish Levels of Service ▶ Integrity and Accountability ● Communications
8
Roadtech 10/23/2013 What are Levels of service? ● Snow Policy ▶ High Levels of Service (Interstates) ▶ Snow Roads (Secondary's) ● Economic Benefits ● Public Expectations
9
Roadtech 10/23/2013 Policy Decisions ● Which chemicals to use ● What amounts to use for various storms and conditions (240lbs lane/mile) ▶ Closed Loop Controllers ● When to apply them for best results ▶ Guidelines (Written)
10
Roadtech 10/23/2013 The Basic Principle It’s much easier to remove snow when it isn’t frozen to the pavement
11
Roadtech 10/23/2013 De-icing ● A reactive approach ▶ Chemicals are applied after the snow has accumulated on the road surface. ▶ Sand and salt are spread on the top of packed snow and ice that has bonded to the road surface. Cost up to 6X-10X to melt snow and ice from the top down vs. from the bottom up. (CRRL)
12
Roadtech 10/23/2013 What is “Anti-icing”? The application of chemicals at the start of a precipitation event in an attempt to prevent or weaken the bond of ice to the pavement by reducing the freezing point of water.
13
Roadtech 10/23/2013 Anti-Icing Strategies ● Require pre-wetting of material, 8 – 10 gallons per lane mile. ● Direct liquid applications, 20 – 40 gallons ( depending on chemical selected) per lane mile. (check calibration) ● Do Not over apply (MgCl 2 or CaCl 2 ). “Be Careful with application rate”. ● Only apply when below 32 degrees F. and not below 15 degrees.
14
Roadtech 10/23/2013 Anti-icing Benefits ● Provides safer roads quicker than deicing ▶ Produces black pavement right after storm ▶ Less labor and fuel cost ● Uses less chemicals ▶ Saves money ▶ Less environmental impact ● Reduces wear on equipment, easier to remove snow and ice when not frozen to road surface.
15
Roadtech 10/23/2013 How Do You decide when to go out? ● Reliable Weather Reports ▶ Location Specific Forecast ● Pavement Temperature Devices ▶ Decisions made on proper info ● Improved Communications
16
Roadtech 10/23/2013 Treatment Factors ● Pavement temperature *Key to Success ● Road conditions ● Weather ▶ Precipitation type ▶ Storm length and intensity ● Traffic volume and timing ▶ Use to your advantage
17
Roadtech 10/23/2013 What’s available ● Sodium Chloride (NaCl) 23.3 % ▶ Blended NaCl 80:20 or 85:15 ● Corrosion Inhibited Magnesium Chloride (MgCl 2 ) 26%-30% (Melt Down) ● Calcium Chloride CaCl 2 (32%) ● Treated Salt NaCl & MagCl 2 ● Others? Wine, Cheese Whey, Beer Waste, Molasses, Beet Juice
18
Roadtech 10/23/2013 Why Anti-ice? ● Creates a brine layer on pavement surface. ▶ Allow snow and ice to be plowed off road easier and quicker ● Prevent ice and snow from bonding to the pavement!
19
Roadtech 10/23/2013 When? ● Anti-Ice ▶ Under what conditions? ▶ What are key indicators? ▶ Can I reapply? Yes or No and Why? Do’s and Don’ts
20
Roadtech 10/23/2013 Anti-Icing Strategy ● Applications will need to be more frequent at lower temperatures or higher snowfall rates. ● Dilution drives the application rate. ● More moisture: ▶ More pounds per lane mile ▶ More frequent applications
21
Roadtech 10/23/2013 Why do you have to use Chemicals? ● Safe roads quicker ● Clear the roads of snow and ice faster ● Less Work Period ● Less accidents
22
Roadtech 10/23/2013 Have to Know how Much you Apply !
23
Roadtech 10/23/2013 Environmental Impact
24
Roadtech 10/23/2013 Chemical Toxicity
25
Roadtech 10/23/2013 Important Facility Procedures ● Good House Keeping ● Don’t Overload Spreaders ● Safety ▶ Back-Up Alarms ▶ Lights ▶ Hard Hats and Vests
26
Roadtech 10/23/2013 What Are You Doing? ● Plowing, not melting! ▶ plowing removes 90% of the snow and ice ● Spread patterns are critical ● Must calibrate to ensure you’re spreading what you want and where.
27
Roadtech 10/23/2013 How do you know When to apply salt? ● Have to Understand, Chemicals depress the freeze point of water. ● If Salt is spread as a solid: ▶ Needs to dissolve in order to work ▶ Takes Time, needs Heat and Moisture ● Spread Liquid Chemicals before an event, to form brine film on road (preventing Ice and Snow from freezing to surface) ● If brine film maintained, last plowing pass leaves a much cleaner road
28
Roadtech 10/23/2013 Melting Rates
29
Roadtech 10/23/2013 Chemical Comparisons
30
Roadtech 10/23/2013 Bounce Scatter Study When spread down the center of the road, only 70% of the rock salt stayed on the road, and 46% stayed in the center of the road.
31
Roadtech 10/23/2013 Bounce Scatter Study When spread down the center of the road, 96% of the solid NaCl Prewetted with CaCl 2 stayed in the road, and 78% stayed in the center of the road.
32
Roadtech 10/23/2013 Prewetting Benefits ● Higher levels of service ▶ Starts melting faster ▶ Melt 10-25% more ice with less material ● Less bounce and scatter ● More environmentally responsible ● More cost effective
33
Roadtech 10/23/2013 This is WHY we Prewet Salt ● Comparison of bounce and scatter, dry and prewetted salt Percent remaining on the road after traffic DryWettedSalt 5 vehicles at 38 mph30%93% 100 vehicles at 38 mph15%80% Source: Michigan DOT
34
Roadtech 10/23/2013 Brine Film Maintenance ● Precipitation dilutes brine, and increases freeze point ● Plowing removes brine soaked in snow ● Bond formation minimized ● Usually need to reapply during storm to keep adequate film on the road ● Reapplication at lower than initial rate
35
Roadtech 10/23/2013 What’s Really Happening? 1.Salt is spread on the ice or snow packed surface 2.Salt melts through the snow or ice forming a brine 3.Remaining snow or ice floats on the brine, breaking its bond with the road surface 4.Vehicular traffic breaks through the surface, reducing the snow/ice to plowable slush and moving it to the road side
36
Roadtech 10/23/2013 Where is Snow and Ice going! ● Closed Loop Ground Speed Material Controllers ● Mandatory Pre-Wetting Materials ● Integrate Technology with Operations
37
Roadtech 10/23/2013 Snow and Ice Tool Box ● Accurate Weather Forecasts ● Pavement Temperature Sensors ● RWIS Stations (portable sites next season) ● Materials – Salt, Pre-Mix and Liquids ● Equipment – Spreaders, Plows etc. ● Personnel –Supervisor’s, Foreman, Operators ● Your Eyes are a very important tool to use.
38
Roadtech 10/23/2013 NEW Tools! ● Tow Plow ● Brine Maker ● Lasers for Wings ● Portable RWIS Stations ● Pavement Temperature Devices ● Segmented Plow Blades
39
Roadtech 10/23/2013 Tow Plow! Currently have 17 across the Commonwealth!
40
Roadtech 10/23/2013 BrineXtreme
41
Roadtech 10/23/2013 Phase Chart for NaCl
42
Roadtech 10/23/2013 Phase Charts NaCL MgCL DOS Possible Refreeze! Active Melting Over Application
43
Roadtech 10/23/2013 Anti-Icing With NaCl Brine ● Application Rate 30-50 Gallons per Lane Mile. ● Lasts on the Road for up to 48 hrs ● Dries on surface leaving “Spray Lines” ● Does not have the same Chemical Residue that MgCl and CaCL have. ● More flexible for Pre-Treating Roads ● Has to be monitored for Dilution Of Solution
44
Roadtech 10/23/2013 Wing Plow Laser
45
Roadtech 10/23/2013 What is RWIS! ● What does it stand for? ● Where do I find it? ● How can it help you? ● What’s the big deal?
46
Roadtech 10/23/2013 RWIS Mounting Structures
47
Roadtech 10/23/2013 Map of Locations
48
Roadtech 10/23/2013 Pavement Temperature Pavement Moisture Frost & Ice Detection Chemical Concentration Freeze Point Temperature Moisture Depth Pavement Temperature Pavement Moisture Frost & Ice Detection Chemical Concentration Freeze Point Temperature Moisture Depth
49
Roadtech 10/23/2013 Weather Forecast Center 24 Hour, Year-Round Staff of 24 Professional Meteorologists www.DOTMETS@TelventDTN.com Toll Free 1-800-994-7947
50
Roadtech 10/23/2013 Importance of Documentation ● Contract Language if use Contractors ▶ Privatize Operations ● Materials Inventory ▶ Shed should have adequate size to hold 75% of winter supply ● Conflict Resolution Procedures
51
Roadtech 10/23/2013 Equipment requirements ● Equipment Configuration
52
Roadtech 10/23/2013 Equipment Required for Multiple lanes
53
Roadtech 10/23/2013 Plowing Operations ● Material Spreader with wing = 14 feet of surface ● Large plow - No wing = 9 feet of surface ● Small Plow = 7.5 ft feet of surface ● Each Combo’s will spread material across 1.5 – 2.0 lanes
54
Roadtech 10/23/2013 Resources ● http://www.clearroads.org http://www.clearroads.org ● http://www.erh.noaa.gov http://www.erh.noaa.gov ● http://sicop.transportation.org ● http://www.aurora- program.org/knowledgebase ● http://rip.trb.org
55
Roadtech 10/23/2013 The 3 T’s ● Timing is everything! ▶ Be prepared ● Trust Technology ▶ New Gadgets do work ● Training is essential at all levels ▶ Train operators as well as consumers ● And be open to new ideas
56
Roadtech 10/23/2013 QUESTIONS? It Will Snow!
Similar presentations
© 2024 SlidePlayer.com. Inc.
All rights reserved.