I have been riding with a Varia Radar RT515 unit basically since they came out and have up until recently NEVER had it miss a vehicle coming up behind me EVER. I know you have to double check, but it's literally been flawless. Some false negatives, but never NOT reporting a vehicle behind me.
Recently (maybe the new firmware) I have noted at least two instances in my last 5 rides when it misses a vehicle. One it missed the second vehicle in a line of vehicles (which I see reported elsewhere), but I have had it happen with a single vehicle too. It's not like it was a small vehicle either.It was a massive GMC 'Duallie' (if not in North America google it). I heard it coming up behind me. Looked down and nothing was being reported on the headunit. No beeps. No visual indication. Nothing. When I'm on group rides it still reports my riding buddies closing on my. Weird and dangerous.
I actually think this is a serious issue that Garmin must look into addressing. This is a safety device and it's now malfunctioning.
