07/09/2012 Council Packet - Laserfiche WebLink

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P40 EXHIBIT B- Revised The Six Cities have concluded that use of traditional sand /salt mixtures should be discontinued in favor of a more comprehensive approach to safe winter roads. Some reasons for the decision are in the following information. "Use of sand (abrasives) An old and widely used practice is spreading abrasives, such as sand or cinders, on the roadway. Although abrasives supply some traction for traffic, contain no chlorides, and are more visible than salt, they have many drawbacks: 1. Abrasives do not break the bond between pavement and ice. 2. They can be covered up or mixed with snow and become useless. 3. They can reduce traction on road surfaces after the snow and ice are gone. 4. They can chip paint and pit windshields. 5. They can clog drains and smother roadside vegetation. 6. They may require costly cleanup efforts after a storm or storm season." (Salt Institute, 1985) "Further, a mix of abrasives and chemical will usually be no more effective as an anti -icing treatment during snowstorms than the same amount of chemical placed alone. It even appears that the use of abrasives in the mix can be detrimental to the effectiveness of the chemical. Because of the cost associated with both application and clean -up of roads and drainage facilities, and because of the potential airborne dust problem accompanying their use, abrasives applications should not be a routine operation of an anti -icing program." * *Manual of Practice for an Effective Anti -icing Program, MHWA Snow and ice - covered roadways that have been treated with abrasives provide friction values that are far less than "bare" or "wet" pavement (NCHRP, page 25). Use of salt /abrasives mixes at moderately or much higher application rates than straight chemical, does not lead to corresponding improvements in hard - braking friction or pavement conditions. Comparisons of test and control operations using identical salt /abrasives mixes show that more frequent applications at similar rates also do not lead to corresponding improvements in friction or pavement conditions and even indicate that the more frequent applications can lead to slightly worse conditions (FHWA 1998, Section 7.4.1 on page 208 of the PDF). The Five Cities plan to implement the Minnesota Department of Transportation Field Handbook for Snowplow Operators for Snow and Ice Control. Included in the manual are recommendations for anti -icing and guidelines for use of salt for deicing. The difficulty of transitioning to anti -icing is the cost of equipment needed. That is where the grant funding comes into play. • • •