Not that I advocate using a "weapon" or anything. I don't think a lot of you are taking this person's initial question too seriously. What is it about your particular environment that causes you to want to use a weapon against someone? And if you feel that is absolutely silly then why?

Personally, I think threatening someone would just make things worse - especially your average over-angry driver. But sometimes at night in the city people get mugged. Not that that happens a lot to people on bicycles. However, I know people who don't think anything of carrying brass knuckles. Most all of the girls on my campus carry mace, or these sharp key chain weapons to use against attackers. I think it's ridiculous, but it comes with living in the middle of the city. The suburbs is a completely different story though....