Secondary position unless travelling at the same speed as the flow of traffic. Never had a puncture. Ever. Kevlar lined tires with puncture strips and a suitable rim width and tyre size to avoid pinch punctures. Same with the wheels, never had a problem. Obviously I don't ride over them if they have been fitted with the drainage slots parallel to the road, in this case I ride an inch or two to the outside. I should mention I ride in all weather all year. Choosing the correct tyres for your environment and riding style is king. In snow and ice I have studded tyres inflated at the correct pressure for the road conditions. Filtering, whether legal and safe or not, gets you no where in the grand scheme of things. It only serves to antagonise other road users. Vehicles can be used as a deadly weapon. Why anyone would do anything to aggravate a driver whilst in such a vulnerable position I don't know. It only takes one driver whos having a bad week, has anger issues, or some other cyclist has caused him damage to his vehicle to snap and end your life. If I'm sat in traffic, I am travelling at the same speed as the flow of traffic, therefore I'm in primary position. I always assume no-one has seen me unless I am in front of them anyway. Again, jumping red lights, undertaking, anything like that is not courteous regardless of it safeness or the legality of it. I am assuming common sense here. Of course I am not going to go around signalling every car to go. If the road is clear and they are waiting for me, I'll let them go before I reach the junction and if its safe to do so. An example to clear that up. The last incident was on a quiet open road, I was in primary position gunning it and a large chap came running to the edge of the road, stopped, looked the other way down the road (I'm watching him to make sure he doesn't go), sees a car. Waits (still looking the other way) then just as I'm around 10m away runs out in front of me and the car. He actually ran in to the side of me lol. I'm pretty sure the car would have flattened him if he hadn't hit me. To sum up I love cycling. When its safe to let go and thrash the crap out of myself, I'll do it with a huge grin on my face. Everything else, filtering, causing traffic to slow down, etc its totally unnecessary.