Ridiculous Potholes

Alien Space Landing Marks?

I logged this series of potholes on the Fill That Hole website (see http://www.fillthathole.org.uk/hazard/59100) Ive seen similar single circles on loads of roads. They are usually cut through 50mm thick top layers to reveal the old road surface so I'm guessing that it is some form of survey work to see how the road is wearing. Sometimes they fill them in and sometimes the filling is missing.

They also use the same size circle to fit the solar powered cats eyes, which they just glue in with bitumen.
Ive ridden over this particular set a few times, and to my knowledge they have never been filled, although the end ones do have some cold fill tarmac in them.
As a cyclist, you notice road surface a lot more, hitting this lot at speed would throw you off and its a busy road so it may lead to a serious injury.
Like I said, its logged on www.fillthathole.org.uk, so we will see how long it takes to fix it!
(Also posted on Google+, see this post)