There are now a number of ebikes equipped with radar systems which warn riders of vehicles approaching from behind. If your bike isn't among those, you can now change that by slapping on Garmin's Varia eRTL615 radar/tail light module.
Garmin Varia eRTL615 Radar for E-Bikes - Bike Shop Girl
Garmin launches e-bike specific radar light - the Varia eRTL615
Garmin Varia eRTL615 eBike Rearview Battery-Free Radar with Wearable4U E-Bank Bundle : Electronics
Garmin Updates Varia System With E-Bike Connectivity
UNBOXING/INFO GARMIN VARIA eRTL615 (Radar and taillight for eBikes)
Battery-free 24 GHz rearview radar and tail light for compatible eBikes (requires compatible Garmin eBike cable; sold separately) Radar detects
Garmin Varia eRTL615, Rearview Radar and Tail Light, Powered by Your Compatible eBike, Visibility up to 1 Mile Away
New E-Bike-Specific Rear Radar Light From Garmin Is Here
New Garmin eRTL615 ebike radar
Garmin Varia eRTL615 launches as a first-gen rear-view radar for e-bikes - News
Garmin releases e-bike specific Varia rearview radar and tail light - BikeBiz
New E-Bike-Specific Rear Radar Light From Garmin Is Here
bike lights
Battery-free 24 GHz rearview radar and tail light for compatible eBikes (requires compatible Garmin eBike cable; sold separately) Radar detects
Garmin Varia eRTL615, Rearview Radar and Tail Light, Powered by Your Compatible eBike, Visibility up to 1 Mile Away
Garmin Support, Varia™ eRTL616
Garmin Varia eRTL615 eBike Rearview Battery-Free Radar with Wearable4U E-Bank Bundle : Electronics