Interesting new gadget, the Varia from Garmin.
A standard mirror is great not because it saves you looking around when you need to move lanes (which you always have to do), but it does save you looking around multiple times. That said, when you’re just riding along on a busy street, the mirror can become extremely uncomfortable as you spy vehicle after vehicle coming at you!
So this new device look promising in that it’ll keep you aware without actually seeing that truck coming up on your rear, and it’ll flash a warning light to the oncoming traffic to remind them that you’re there. It’ll also work with many current Garmin devices. However, it’s not cheap! Check out Time Magazine’s review on the new device.
It’s blind spot detection for your bicycle