Sorry, this is a really basic question.
I am trying to equally divide my game area into 3 lanes in a Unity 2D project to create an endless runner. I am wondering if there is a less fiddly way than dragging and dropping sprites for lane separators?
You can write a script to do this job for you. However in order to point you towards the actual logic we would need details about how you are generating the lanes, how they are laid out, etc.