This might be a bit of a long shot but I notice in Kofu there's a hell of a lot of construction work going on by the Arakawa river, I think its on route 52.
The picture they've got on display seems to suggest they're making a 4 lane bridge rather than the current 2 lane one but....how they're aiming this is unknown to me- I suspected it was to be away from the current landing point of the bridge and across a vacant plot, so as to aim towards the resumption of the 4 lane road, but the placement of the bridge supports suggests otherwise.
They also seem to be doing a lot down by the river. Dumping lots of soil in the middle of the river and making access points down to there, its almost as if they're making new roads next to the river....but considering the park those roads would be replacing was flooded just the other month in typhoon season and is low enough it seems to be a regular thing...this seems mad.

Has anyone read anything about what is going on here?

If you have a look in Google Earth at that point and use the "historic images" feature, then you see that there were a 4 lane bridge before, but it seems like it's need to be replaced so that they have built a temporary 2 lane one that is a bit twisty...

To me it looks like a simple replacement.

aha, hadn't thought to check that, strange. And from above in 2010 the image of the unused roads looks quite clear whilst on the ground it doesn't.
Wonder what happened to the old one though. And what they're doing to the river.