easement

Washington State :
I have a easement on south end of my property for ingress and egress. The back acreage sold a few years ago, and the easement went with this property. Here's the problem: the current owners son, and daughter see fit to let almost anyone use this property, thus increasing the traffic down my private drive. We received a note from the son that if any vechiles were left unattended that they would have them towed off my property. My question is :what are my rights on this easement ?
I say that i own the land the easement is on, and i'am conveying him the right to use this easement to access his property.

[I AM ALWAYS LIABLE]

My response:

What "you say" and what your deed and survey of your land says may be different. When was the last time you reviewed your deed, or deed of trust, for the exact verbiage concerning the easement ?

If your deed and survey bear out your contentions concerning the easement conveyance, location, dimensions, and rights, I would send him a copy of both your deed and survey and tell him that you're "turning the tables" on him by saying, "Okay, now these are my rules, pal . . . "

IAAL