Don't get run over. That's not good for knee rehab .
High power dayilight-visible flasher on the back of your helmet - something with a fairly wide angle like a Niterider Solas https://www.niterider.com/product/solas-40/
or xeccon geinea http://www.amazon.com/Xeccon-Geinea-SAMSUNG-Batter...
Or Gemini Iris. http://gemini-lights.com/products/iris-rear-light
These all blow away the old Planet Bike Superflash turbos.
...and maybe run your headlamp on flashing?
We don't want to lose you!