How to avoid empty vehicle travel

Hello,

I am wondering how can I avoid empty travel in a route. Is there a way to avoid this and make the route ends or returns to the depot when the vehicle is empty.

Thanks in advance

I have a hard constraint that is to avoid empty traveling, i mean when the load of vehicle is 0 ->the route ends.

is there any way to avoid this by assigning high cost for those travel or adding a hard constraint ?