What explains this pavement wear pattern?

[Pete from Boston]

We were driving the MA 140 expressway from Taunton to New Bedford, MA the other day, and noticed that the wear in the generally worn-out pavement was worst along the centerline.  Open potholes right through to the next layer down occurred at irregular but frequent intervals in the width occupied by the dashes of the broken white line between lanes.

It didn't appear to be wear along where markings were scraped off, thanks to the lack of other evidence and the irregularity of the holes, but for miles these potholes followed the path of the white line. 

Why?

[Crazy Volvo Guy]

Because Massachusetts uses (or used) oil-based paint for the lane markings, and oil breaks down asphalt.

[hbelkins]

Also, that is the seam between the two lanes, where water can get down into the pavement.

[Alps]

This is happening constantly along the I-287 reconstruction north of Morristown, and I believe a contributory factor is the existence of original concrete pavement somewhere underneath. Still, it's much worse at the reconstruction because now all traffic is constantly running over the lines there instead of the occasional car changing lanes.