Don Norris wrote:
Yes, setting the alerts reduces the pop-up boxes, but not the number of little arrows flying about you.
Go back to the same settings window (Menu > Setup > Alerts and Warnings > Traffic Alerts). The "Set Alert Thresholds" setting does what you say--it changes when alerts pop up, but doesn't change the arrows flying around you.
But there are two more settings right below that that adresss Henry's question: "Distance Visibility" (how far away you want to be able to see traffic) and "Vertical Clearance Visibility" (how far above or below you want to be able to see traffic).