Seasonal load restrictions are necessary on specified routes to prevent extensive pavement surface damage. When snow, ice and frozen ground thaw in late winter and early spring, some road beds and base gravel become saturated and their ability to carry truck loads is reduced. The potential for severe road distress during the freeze-thaw cycles is high. Older roads are more susceptible to frost action than roads constructed to current Highway District Standards on free draining (good) subsurface soils. To protect our investments and to keep roads serviceable, load restrictions and speed limits must be placed on vulnerable roads.

More specifically, during winter months, the moisture found in the soils and gravels below a road’s surface freezes.  The depth of this frost zone varies depending upon the length and severity of the winter season. This frozen zone begins to thaw from the surface down, at varying rates. The moisture released by the thawing soils and gravels is trapped near the surface between the pavement and frozen soil below.  When this occurs, the overhead passage of heavy trucks and equipment can create a “bouncing” or “pumping” effect on the trapped moisture layer, which can severely damage the roadway’s structural integrity and significantly decrease its lifespan.    

Spring breakup restrictions are required to mitigate this characteristic seasonal freeze/thaw cycle, which makes the roadway unstable and reduced its load-bearing capacity.  These load restrictions are weather dependent – not calendar based.  Such restrictions are normally required throughout the spring breakup season that can start as early as January and extend into April.  

Depending upon the type of road construction, the amount of moisture, temperature conditions and the severity of frost heaves and breakup, roads or sections of roads, the following restrictions will be posted in order to protect the roadway and to ensure public safety:  

 1. Maximum of 10,000 pounds on steering axle (9 inch minimum tire width)

2. Maximum of 300 pounds per inch of tire – all other axles

The load bearing capacity of a roadway may be temporarily restored by a freeze-up of the pavement after a section has been posted for load and speed restrictions.  Typically, during cold weather snaps, trucks and heavy equipment may be granted access to roadways after average daily  temperatures have dropped to 20 degrees Fahrenheit for three consecutive days.     

Each year, at the onset of snow and ice melt and stretches of warm weather, weight limits are posted.  Signs designating these regulations will be posted and maintained throughout the District and announcements made through press releases to the local media.   The District will also notify local contractors and transportation companies that would ordinarily be impacted by the institution of road weight limits. 

What we do to determine when load limits are applied:  We utilize multiple different methods of verifying when we apply or remove load limits.  We utilize theorical methods of evaluating temperature to give us an idea when we need to be looking closer at other the methods such as: surface monitoring roads for indicators of weakened layers below and physically excavating exploratory holes adjacent to the roadbed or pounding steel rods to verify frost depth.

Ultimately, it’s about verifying whether or not our roads are capable of supporting loaded trucks.  With moisture getting into our road beds a partially melted undrained roadbed creates a weakened structural support below the pavement, causing premature failure and costly repairs.   

The first method we use is a theorical technique originally developed by the Minnesota DOT and adopted by many other local agencies such as the Washington Department of Transportation and Bonner County.  With this method, we record average daily temperature throughout the late fall, winter and spring.  By monitoring average daily temperature this gives us guidance on when to apply load limits and for the durations necessary to restrict loaded vehicles on our roads.    

We also physically monitor our roads.  Typically, in January or February, when we begin to see warming temperatures, we closely look for indicators that the frost is coming out of the frozen road bed.  A key indicator of melting is water seepage through cracks in the road and/or frost heaves or bumps in the road. 

Once we’ve determined that load limits should be applied, we’ll often physically verify frost depths throughout our District by excavating a small hole next to a road or driving steel rods.  When we do this, we look for the depth of frost and moisture above that frost level that is not able to escape.  Basically, undrained moisture over a frozen layer significantly reduces the strength of the road and is a recipe for major road failures if heavy trucks are allowed to operate.  It’s not unlike driving a vehicle into your yard in the spring; you’ll leave wheel tracks.  For paved roads, the pavements flex beyond their capability, they rut and then crack causing significant cost to repair.

Given the different methods that we use for determining when to apply or remove load limits, we have a better than good understanding of when we should apply 

City of Spirit Lake Snow Removal Plan Public Works Department Operations

Each year, the city of Spirit Lake, Idaho experiences, on average, approximately 52 inches of snowfall. Winter weather conditions typically occur between November and March. The rate of accumulation of snowfall, moisture content, temperature, time of day, visibility, wind velocity and duration are all variables that interact to create unique road conditions for each storm. 

Responding to winter weather conditions requires a collaboration between the City and its citizens. The City currently dedicates its entire Public Works department staff to operate equipment and tackle snow, ice, and slush. Their mission is to provide the greatest level of service to the traveling public. The City monitors winter weather conditions daily to provide a proactive response and strives to continuously improve operations to best serve citizens.

The goal of the City’s snow plan is to establish a system of priorities that facilitate keeping winter traffic moving as safely as possible. Also included in the snow plan are some tips on how to best deal with snow and ice more effectively. 

As in previous years, when it snows 4 inches or more, City crews will begin to plow all streets, including all residential streets. The response plan provides:

·        Proactive pretreatment of high priority, heavily traveled roads and intersections

·        Crew members prepared in advance for nighttime/early morning coverage

·        Emphasis on streets with emergency services and schools/bus routes

·        Emphasis on streets with steep grades or curves

·        Seasonal parking rules (see list below)

·        Proactive cleanup in preparation for forecasted snow events 

It is impractical, both physically and fiscally, to give all streets equal level of services and maintain near continuous coverage. Consistent with other municipalities, available resources focus on the streets most traveled and on those that provide access to essential services. Streets with higher intensity use have a higher priority for snow removal. Residential streets require proportionally more time for snow removal for less traffic served and therefor have a lower priority.

No Parking Zones- There shall be no parking of any vehicles during the prohibited period of November 1st through March 31st from 2:00 AM through 6:00 AM on Maine Street from the west city limits to 5th Avenue, inclusive, as outlined in Spirit Lake City Code 6-1-3A and 6-1-3B. This allows for adequate snow plowing of the Maine Street corridor and adjacent parking. 

Snow Removal Obstruction Prohibited- It shall be illegal for any vehicle to be parked in such a manner as to inhibit snow removal operations after notification to the owner/operator by a City employee or official, as outlined in Spirit Lake Code 6-1-3C.

The Right-of-Way- Any personal items in the city right-of-way need to be removed by November 1st each year. Cars, trucks, boats, trailers, basketball hoops, and miscellaneous items all need to be removed before plowing season. Vehicles left in the right-of-way are subject to citation, towing at the owner’s expense, or both.

·        It is the homeowner’s responsibility to clear the snow around mailboxes and newspaper boxes.

·        Items left in the right-of-way are there at your own risk and could be struck by a snowplow during plowing.

·        In the event of damage to snow removal equipment caused by items in the right-of-way, the property owner may be responsible for the cost of damages to City equipment.

·        Garbage/recycling cans need to be removed within 12 hours of pick up from the street and are at risk of being damaged by snowplows. Cost of replacement of damaged cans will not be covered by the City.  

 

Unlawful Act- Unlawful Act: It is unlawful for any operator of snow removal equipment or the owner of any land upon which snow removal equipment is operated to place or otherwise permit, sanction, approve or cause the placement of any snow onto public property or right-of-way upon its removal from privately owned land or for any person to deposit, cause to be deposited, thrown upon or move onto any public property or right-of-way any snow/ice, dirt, soil, rocks or debris which has accumulated on any private property, that constitutes a safety hazard or impedance to City workers, and/or the general public. Spirit Lake City Code 5-2-4A.

Sidewalks- It is the duty and responsibility of the property owner to maintain any sidewalk abutting his/her property in a clean, snow/ice free condition, and ensure the surface of said sidewalk is maintained in a safe and proper physical condition as outlined in Spirit Lake City Code 7-2-4.

Areas of Concern- Keep ADA ramps, mailboxes, and fire hydrants free of snow and ice. Keep everyone’s safety in mind!

·       Have adequate snow shovels or a working snow blower

·       Consider purchasing salt or sand to help tackle ice and slippery conditions

·       Shake tree branches of heavy snow. Snow can cause damage to healthy trees and fall on pedestrians passing by.

·       Know who in your neighborhood might need help with shoveling or other winter work and offer to help. Winter can be especially tough on seniors and disabled individuals.  

 

Sand and/or deicer is used in combination with plowing to provide reasonable driving surfaces in icy conditions. Spot sanding will be done at specific locations on primary and secondary routes, and at inclined intersection approaches as needed. 

Unfortunately, the city snowplows are NOT equipped with snow gates. Our goal is to clear the roadway for safe travel, and berms are an inconvenient result of plowing. 

·        Some citizens who may be incapable of plowing or shoveling their snow berms may be eligible to be added to the City’s “No-Berm” list. To be eligible you must meet certain criteria by providing proof of physical limitations, injury, or illness from your physician, with no one else living in your residence who is able to address the berm. You may contact City Hall for arrangements to be added to that registry. 

Please contact Public Works Department at City Hall. Please do not try to stop plow drivers and address your complaints with them. They are doing the best they can with the pressure of getting the whole city plowed.