What caused the pattern of rectangular holes in M-14 freeway for several miles between Ann Arbor and I-275?

Question

This freeway is in southeastern Michigan. What makes this so odd is that they just finished working on that stretch of M-14 not too long ago. Then several months ago, out of nowhere I started seeing these holes on the eastbound and westbound lanes. I was wondering if anyone else noticed them and if anybody had any idea of where the holes came from. The holes are uniform and occur in intervals which suggests that they weren't caused by the weathering that usually takes it toll on Michigan roads.

Answer 1

Aliens.