WMOD00556

• Title: A Simulation of the Costs of Removing Snow from County Highways in Colorado
• Date: 3/1/1983
• Weather Modification - Doc Type: Report

The Simulation M:xlel.

; .

The simulation model estimates snow :removal costs using information
about wages, machines and removal procedures gathered I::!i interviewi~
road maintenance foremen in each county and daily snow amounts recorded
at National Weather Service cooperative ob;erver sites. Snowfall records
from past winters were used so costs could be estimated for winters of
low, average and high snowfall. The model also estimates costs of mop-up
(pushing back banks, clearing drifts and sanding slick. spots on days
following storms) and overtime.

Labor costs are conputed only for thl~ time employees spend removing
snow. Labor of mechanics is included in the "rental rate" applied to
each machine. The labor of office staff is excluded because it is
difficult to tie their duties to daily snowfall. Costs of supplies are
excluded, because they are difficult to determine and because initial
estimates indicate that they are insignificant compared to costs of labor
and machines. Costs of operating, maintciining and repairing equipnent
were estimated by using hourly "rental rat.es" calculated by. the Colorado
Department of Highways.

Foremen reported that the effort required to remove given amounts
of snow depends on characteristics of storms such as wind, density of
snow, time of day and duration. we developed methods to account for time
of day and duration: wind and density of snow were accounted for by
asking foremen to "abstract away" the extreme and consider typical
conditions.

Simulated Augmentation of Snow Amounts.

The simulation model can estimate snow removal costs when recorded
snowfall amounts are increased to simulatE~ effeCts of seeding. In this
study, snow amounts in a random sample of one-third of the storms in the
winters examined. are increased 25 percent. 'lWenty-five percent was
chosen because Colorado State University scientists have indicated that
these increases in snowfall are possible if storms are seeded carefully
and knowledgeably. Snow amounts were augmented in only one-third of the
storms because meteorological conditions favorable to seeding are thought
to exist in about one-third of the winter storms in the Colorado
mountains. This augmentation scheme resulted in increases in seasonal
snowfall which ranged from 4.5 to 9.7 percent.

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