WHY ARE RESTICTIONS PUT INTO PLACE? When the ground begins to thaw after a significant freeze it starts from the top down. The water has no where to go so it pools and builds up in the ground immediately below the pavement. The
pavement is relatively thin and cannot support the weight of heavy vehicles and it soon begins to break up causing ruts and potholes.
HOW IS PAVEMENT DAMAGED BY A FREEZE/THAW EVENT? When the road base freezes below the asphalt surface, water is frozen in the road base. When thawing begins, the base thaws from the top down. Trapped water can’t drain through the frozen base below. The base, now full of water, can’t support heavy loads.
Truck traffic deforms cracks or breaks up the asphalt road as water is pumped to the surface.
WHAT CAUSES THE PROBLEMS? The roads are restricted for a period of days to allow the water to absorb into the ground and the base of the road to restabilize. At first, the thawing ground is like a big bowl of pudding. Any weight on the
road will just squish the substructure out of place. When this happens over and over, as on a highly travelled collector, the damage can be catastrophic,
causing thousands, or even millions of dollars to mitigate. To repair the damage, we often
have to dig down several feet to remove the compromised substructure and replace it with new. With over 1000 miles of road in the county, you can imagine how the costs of this could build up,
causing the delay or abandonment of other projects.
HOW LONG WILL THE RESTRICTION LAST? Road restrictions are
in effect until the road base is thawed, and water has drained out of the
road base. When this happens, the road base is stabilized. How long this
process takes can vary greatly due to weather conditions.
IS THIS THE FIRST TIME YOU'VE DONE THIS? The last time Thurston County implemented county-wide restrictions was 10 years ago. It is not something we take lightly.
WHO MAKES THE DECISION? The calculations are made by Civil Engineers. We utilize weather reports and weather projections to calculate when restrictions should be placed and removed along with gathering field data on depth of freeze and thaw conditions. The proposal is then
put before the Public Works Director and the Board of County Commissioners.
WHAT ABOUT MY FUEL DELIVERY FOR MY HOME HEATING? Delivery of life sustaining items such as propane or home fuel is still allowed under the restrictions. Companies delivering these and certain other perishable or critical products can continue deliveries, although they may have to carry reduced loads.
If your vendor is telling you otherwise, you can ask them to call the county
WHAT ABOUT TRASH PICKUP? Garbage pickup may be allowed, however trucks would not be able to run at full capacity, thereby requiring more trips. Because of this, carriers may opt to delay pickup. This decsion is up
to the Waste contractor and not the County. Should you have questions about this, we refer you to your trash collection company.
WHAT COUNTY ROADS ARE AFFECTED? All roads in Thurston County that are not under the jurisdiction of another municipality, agency, or entity. We have produced a map that you can view
HERE, with the
included roads in PURPLE.
HOW DO I KNOW IF MY VEHICLE IS RESTRICTED? Here is a chart.
WHERE CAN I GET MORE INFORMATION? You can call us at 360-867-2300.