Yeah, it might seem like you just "know" people are going to do something stupid at times, but it's just down to subconsciously noticing that they've just done/are doing something unusual... they're looking the wrong way, not slowing down quickly enough, the lights behind you are getting a bit too bright a bit too quickly... stuff that sets off alarm bells, especially when coupled with experience.

It happens so quickly at times and the alarm bells ring at the first sign of danger, it can really feel like you just knew something was wrong, rather than being based on any real evidence. Just trust that intuition - if something doesn't feel right, don't trust the b@st@rds!

I dont know much about sixth sense,but we do have an ability to think subconsiously.Many times I have found myself taking avoiding action for a hazard I didnt know I had seen.Periferal vision plays a part here too.You see things without looking at them but you still react accordingly.

its down to experience mainly.....I glare at other road users, I feel both defensive and aggressive when I am out on the bike. I have a completely different attitude riding in traffic than I do when riding down a deserted country lane.....

I am sooooo observant, I see everything...though I am sure that riding a bike does heighten your awareness thus making it seem like you have a sixth sense.