Brilliant Back-Pack Covers.
No need to buy a new bag to get yourself noticed, just grab one of these bright, neon yellow reflective waterproof numbers. They're a must-have item for wet months when you're out and about - especially if you're near traffic. The one-size-fits-all elasticised cover fits right over the front and sides of your pack. Two straps then secure the cover to the bag - and keep yourself seen.