Varia radar alerts on a Vivoactive 3.

It appears that the Vivoactive 3 vibrates when the radar decects traffic, but only if the Garmin provided "Bike" app is active.  Is there a way to activate the radar alert without having to start this app.  Are there any other Garmin or third party cycling apps the use the radar.

A request to Garmin:  Lengthen the vibrating signal for the Varia.  It's too short.  A longer signal would be much more noticable on the road, particularly a rough road.