I think I single-handedly averted an accident yestyerday morning on route into work, while causing another much less serious one.
The traffic was building up behind the dustcart which was alternating between crawl and stop in front of us as the dustmen legged it to and fro with sacks from the ribbon development. Traffic gaps coming towards us were few and far between, and a cul-de-sac on the left was looming as I got to two behind the dustcart. The road was at that point gently curving left. I hugged the left kerb, leaning left - hanging back - to get best view of everything. A white van was rapidly moving up the cul-de-sac, having seen the dustcart holding up traffic on his right and a gap in traffic from his left adequate for him to turn right in to. Sadly (or not) the car immediately behind the dust cart was both too close to the cart and on the crown of the road. He would not have seen white van man. That car was cautiously easing to cross the centre line and when he realised nothing was coming, he booted it - just at the time that the white van decided that I was in pole position to take the dustcart and, because I was hanging back and left, was prepared to let him go. He booted it too. I laid on the hooter for 4 seconds, despite at that time not bring able to see much/any of either of the collision course vehicles. Both evidently slowed - and worked out how to avoid one another.
The accident I caused? A young dustman dropped a sack as my hooter caught him - which in turn spewed its contents over the road.

All the dustmen glared at me, thinking I was taking umbridge at their road hogging. Oh well!