Question
I have Arborvitaes at the end of my drive way covering up the neighbors rock wall these trees are getting two big in growing out into my drive way and some bare spots. can I cut back the branches and will they re grow new ones. can you help

Answer
If you "hedge" back the green parts of the branches, they will re-grow, but if you shave off the green leaves/needles exposing the second-year woody grown underneath, it will remain bare for wuite a while, and take more time to recover.  There is technically a difference between 'trimming' with lopers & scissors & 'shearing' with a hedger.  Arborvtae can endure both methods.

They usually don't grow new branches from the affected area that is pruned heavily (where you see the woody branches underneath). If they are healthy, the new growth will occur at the head or green part of the plant.  

For best results, only trim the top leaders. Since arborvitae do not have buds, they can be trimmed any time of the year. The green ends are actually "growth points" at the tip, and not true leaves.

Most arborvitaes are upright in growth habit.  It think it looks better if you trim back the branches to the center of the plant, in my opinion.  I have one in my side yard that is probably 20+ years old, and has been pruned into a tree form (the bottom branches were removed before we moved in).  

If yours is overgrowing the space, maybe it is time to consider replacing them with a more size-appropriate plant?  

~Marc