The dips in the roads

I have never said I was a roads expert so Wednesday I spoke with someone who has forgotten more than I will even know on the subject. Jeff, our maintenance manager, has extensive road construction experience and he had the answers.
These dips that are in the roads are due in the main part to the materials we are making utility companies use when tunneling utility lines under the road. We are insisting on flowable fill, which is pretty much as it sounds. It goes in in semi liquid form then hardens almost like cement so it will be stable. The dips are not there because the area sunk, they are at the actual elevation of our road under normal conditions. This year as the frost went deeper and deeper it raised the road bed due to the expansion from the moisture in the base. Our roads actually raised substantially and to some degree will drop back with the thaw but how much we will not know until it happens.
Jeff is on top of this and it will be handled in time. Just bear with the roller coaster ride until we see what happens. Anyone who has driven other area roads knows we are far from alone in this problem.
Ken