I did a pool tri last Saturday. The athletes grouped together with those who swam the distance at roughly the same time. Then we lined up and every ten seconds, one athlete crossed the timing line and jumped into the pool (I don't recommend diving as the pool may be crowded). The lanes were very full. While I liked it better than an open water swim, there was still some accidental kicking and passing collisions going on. I learned if one is a slower swimmer, there is a wide variety of strokes used and even those who will walk the distance (which is legal as far as I know). This led to "clogs" where I had to stop in the middle of the pool and wait to pass. There was an "up and back" in a lane, then I had to duck under the lane line to another "up and back" until I swam 300 meters-a serpentine. It isn't as peaceful as swimming practice laps. It was more like an open water swim. 
So to sum it up, depending on the length of the pool and of the swim, there could many athletes going both directions in each lane. I could pass, but had to wait until the oncoming traffic allowed for it.
Good luck and you will have a GREAT time!
Last edited by Lifesgreat; 05-23-2008 at 05:40 AM.
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