- Why isn't road closure listed as a cost of blowing a drifting snow? It is correct that the road closures have not been taken into account as part of the blowing snow web tool. It can be a very challenging cost to arrive at and seems to require traffic modeling to determine what drivers do when the road is closed. Do they take an alternate route? Does this create slower traffic on these other routes? What is the AADT of these other routes? One thing that is unique to blowing snow closures is that the AADT might overestimate the number of drivers that are impacted by the road closure. This is because the weather conditions would likely reduce traffic even if the road stayed open. Other folks have included road closures in their cost benefit tool. They took the AADT multiplied by the fraction of the day that it was closed and multiplied it by the auto-value of travel time savings per person-hour. The underlying assumption here is that when a driver runs into a road closure they just sit and wait for the road to open with nothing else to do. We also need to remember that our analysis is for each snow problem segment. Most roads would require solutions at multiple snow problem segments to keep the road open. So the economic benefit of keeping a road open would need to be divided among all the snow problem segments.
- Why is land rental not used in standing corn rows when it is used for a living snow fence or structural snow fence? The reason for this is that with living and structural snow fences, land is taken out of production. With standing corn rows, land is not taken out of production. To see the detailed calculations and explanations, read the sections of the Inputs page related to each of these snow control solutions.
- How are as-builts used in the tool? Please see the as-built section of the Inputs page for general details on using the as-built checkboxes. For specifics about how the as-built checkboxes work for each section, including in the results, see those sections of the user guide.
- When entering equipment mileage does the user enter round trip or one-way values? Equipment mileage should be entered as total miles. See the equipment section on the Inputs page for more details.
- Weather can vary from year to year. What values do I use in the tool? Because the values can vary from year to year, it is best to use long-run annual averages for all the data entered in the tool. Using last year's data will not give a good indication of the return on a snow control solution over time. The best practice is to average the data over 10 years or more or use the data from a winter that is an average winter. To help determine what an average winter looks like, see the Minnesota Winter Misery Index.
- How do I interpret the results? How do I know if I should control blowing a drifting snow? The exact criteria for determining which snow control solution to use at a blowing snow problem site will depend upon the program policies specific to each agency. To better understand the results, please read the Outputs section, including the details for each metric. In general, sites will fall into three categories (Note: Your agency may use different thresholds for metrics to determine the best projects to allocate its resources to. For example, the money that would be spent on snow control could be used on another project with a high cost-benefit ratio. This cost-benefit ratio should be used as the critical threshold and not the default.)
- Cost-benefit ratio less than one—return on investment (ROI) less than the agency discount rate—for the agency and society. These sites are poor investments because they will cost the agency and society more than the benefits.
- Cost-benefit ratio less than one for the agency but greater than one for society. These sites are the most difficult to assess. They will cost the agency more over time but will have a benefit to society. They are similar to road construction projects in that aspect. The agency will not see a return, but society will.
- Cost-benefit ratio greater than one for the agency and society. These sites are good investments both for the agency and society. Over time, these sites will reduce the costs to the agency and have positive net benefits to society.