Sanding roads may cost more than salting
Last week’s article discussed some of the things to consider when deciding whether to use salt on roads for snow and ice control or abrasives, such as sand. Most people would guess that using abrasives is far cheaper than using salt. Maybe not!
Here is some information that most citizens aren’t aware of, and in many cases, village and town boards aren’t, either.
About five years ago I attended a day-long workshop on “Snow and Ice Control.” This workshop is designed for municipal highway superintendents to increase their knowledge of prudent sanding and salting of roads. These workshops are sponsored by Cornell Local Roads Program. The instructor was Duane Amsler Sr., P.E., a licensed professional engineer with extensive experience in snow and ice control procedures, products, management, operations, research and technology, with nearly 50 years of experience in highway operations and maintenance.
Because municipalities that use sand on their roads must mix the sand with salt to prevent the sand piles from freezing and chunks from forming in the spreader, and to aid in “sticking” the abrasives to a snow or ice surface, applying sand also applies salt, although not enough to accomplish much significant ice melting or brine forming on the pavement. However, the 7-10% salt added to abrasives is more than enough to create many of the environmental and corrosion problems normally associated with salt.
Application rates normally associated with salting roads is about 125 to 225 pounds per lane mile, whereas application rates for spreading sand is approximately 750 to 1,000 pounds per lane mile. At these rates of application and with the sand containing nearly 10% salt, you can see that even sanding the roads applies nearly 100 pounds of salt per lane mile. Furthermore, when using abrasives, they do not retain their effectiveness long. Displacement by traffic or incorporation into forming pack quickly diminishes the benefit. Consequently, frequent reapplication of sand is necessary.
When all the above is considered, along with the approximate cost of salt ($50 per ton at the time of the workshop) and sand ($11 per ton), each application of abrasives actually costs about the same as an application of salt. The estimated cost to treat one lane-mile with salt only was $5.63 versus abrasives with salt mixed in at $5.70.
As abrasives have to be applied more frequently, salt can actually cost less to use than sand. When the cleanup costs associated with abrasives are considered, they are far more costly to use than salt. Furthermore, because of the much higher rates of application of sand over salt, the trucks can’t cover anywhere near the miles when spreading sand that they can by spreading salt. Thus, there are increased costs for diesel fuel and more wear and tear on the trucks.
As the controversy of salting roads continues, another thing to consider is safety. If a Department of Public Works or the New York State Department of Transportation doesn’t do what’s considered a reasonable job of keeping our roads as safe as possible during winter, that could expose the municipality or state to tort liability. So deciding to use sand versus salt, and just how to much of either to apply and when to apply it, is a science in itself.
Other points that also need to be considered include:
¯ Pre-wetting the salt or using liquids is also an important part of using the correct amount of salt.
¯ Too much salt is a known issue.
¯ Equipment must be calibrated and maintained to disperse the materials correctly and use the proper amount for the existing conditions.
There’s a lot more to consider than meets the eye. At the end of the day, it is important to realize that the application of snow and ice control materials can and should be designed to meet the site conditions, level of service and weather for a given community. The bottom line is salt is now considered by the experts as the treatment of choice in most cases.