Why Are There Seasonal Road Restrictions In ND?

I know what you're saying to yourself...what kind of morons don't know that? I guess my kinda morons.

I'm a lifelong North Dakotan, but..

I've never milked a cow or slopped a pig.  I've never been in a moving combine nor have I driven a tractor. But, I have shot about every kind of critter and field dressed deer.  So I have some level of North Dakota "cred".

But honestly if some kid were to ask me why there are seasonal load restrictions, I would come up with some sort of Cliff Clavin answer to cover my ignorance.  Remember Cliff?  He was the mailman on the TV show Cheers. He always had some BS statement that often started out with- "well, y'know- it's a little known fact...".  So my answer to the kid's question would have been "because of the roads".  That ain't saying much, because that's about all I know.

Well, Monday March 15th Seasonal Load Restrictions will be put in place for additional North Dakota Highways.  If you want to learn where...click here.  If you're like me and all you drive is a car, maybe you're more interested in the "why" than in the "where".

Let's consult with the NDDOT...

Falling Weight Deflectometer (FWD). This equipment measures the strength of roadway bases, as well as the asphalt pavement surface. The NDDOT utilizes the FWD to evaluate pavement strengths for purposes of forecasting when load restrictions may be initiated and removed.

Wait a minute... "Falling Weight Deflectometer"?  Suddenly, I'm feeling a little less like a moron.  Seems the highest amount of road damage occurs in the spring months 

As the frost is leaving the ground during the spring thaw every year, the gravel under the roadbed has high moisture content, which weakens the load carrying capacity of the bituminous (asphalt concrete) road. 

So it's not so much the condition of the roadway to the human eye, but instead it's what lies beneath. Then it's experts with their FWDs and years of knowledge and experience that are making the call and trying to extend the life of our roadways.

Next up...I figure out- what's going on at those highway "weigh stations"