We were there, and thought to be able to drive part of the way. There was a sign Road closed at the beginning and concrete blocks on the road after the thater. You can pass on foot or by bike as its park of long distance hiking trail E6 (you find some very old rusty signs...)
Bulldozers have mad the road twice as wide as expected on the satellite images, they are now doing conrete tunnels for the streams. we saw people working on huge concrete structures for one tunnel and they had already done a few. Some farmers drive around the blocks through the vegetation to reach their flocks, but you should not be guided there with navigation systems (thats why I would mark the road as closed).
It seems, the road is closed for several months now and it will take them probably another 6 or twelve months, but I think it's a project of a major road along the coastline and not just minor roadworks on a track used by farmers, probably the new  road will connect Alexandropouli - Dikelly with Maroneia. There is no end date for the works, but it seems they are really doing a major new road construction. I do not know how to tag better, but it should be clear, that you cannot pass by car and can follow the E6 trail on foot and by bike, regards from Switzerland Martin