Sarti is at the bottom of the second leg (Sithonia) of Halkidiki, it was abandoned until the early 20th century when Greeks wrelocated from Asia Minor re-inhabited the village.
Until the 1960’s access to Sarti was mainly by boat. The ring road around Sithonia was completed around the 60s and this is when Sarti had paved road access. While specific details of the date of the road is hard to come by, from the width of the road you can see that the road from Vourvourou down and around to Porto Koufo was built in the same era. The road from Vourvourou to Porto Koufo is noticeable wider than the old road from Port Koufo back to Nikiti
This video gives a brief history of Sarti
This website is dedicated to the history of Sarti
More Sarti history can be seen here https://halkidiki-greece.com/en/sithonia/sithonia-villages/sarti/sarti-history-information.html