I'm a huge advocate for using radar devices when riding (under most circumstances). One feature I'd like to see is a "Quick Mute" option on the Edge units to use when in heavy traffic or riding for prolonged periods near high traffic roads where the radar is continually detecting passing traffic. The audio alerts become white noise in these instances. Riding in a city in recent days I've resorted to switching the radar off as a quick stop-gap when I'm in heavy traffic - not ideal but it does the job.
A quick pull-down widget option to 'Mute Radar' would be brilliant. Similar to the quick control menu pull-down for 'Bike Alarm', 'Power Meter Calibrate', etc, where the radar audible alerts are muted and that mute status shown on screen:
