Work on the plots / houses will only begin once the road is finished.
Why? A construction access road is sufficient to build a house. You will only become wiser if someone who is knowledgeable in this area reviews the entire (!!!!) contract. In my opinion, it would not be any different if you had agreed on a penalty clause. So go to a construction law attorney ... Before that, it might really be a good idea to go to the developer, make it clear to them in a friendly but firm manner what the delay means for you, and try to find a way together to speed things up. Normally, the developer also wants to finish quickly since they get paid by you based on construction progress. You are welcome to report here how it continues ...
