We have a remote location where there is only one road in and out of the site. I have setup a zone on the road leading to the site so when a vehicle enters the zone it sends an email alert to the store person that a vehicle will be arriving in around 15 minutes and it works great. What is happening is when the vehicle stops at the store and then returns on the road it sends the alert again. The maximum time the vehicle would be at the store is one hour. Any ideas how I could stop it sending the second alert?