New Varia™ rearview radar from Garmin is the world’s first cycling radar and helps create a safer cycling environment by warning cyclists of vehicles approaching from behind up to 140 meters (153 yards). It also warns approaching vehicles of a cyclist ahead.
Works independently and integrates seamlessly with the Garmin Edge 1000 cycling computer. Edge computer or Varia head unit indicates the relative speed of approach and distance of one or more vehicles at a time.

To learn more about the Varia™ bike radar look here: https://buy.garmin.com/en-US/US/p/518151