Luckily my current commute doesn't require taking the lane, but back when it did I felt best taking the lane when I was within 10mph of auto traffic speed. Many say to take the lane on 3 lane roads cuz the cars have two other lanes to drive fast in. No way in hell I'd do that in when I lived in PHX, though. That city is a grid of 3-lane roads and being in the lane is a nightmare. Luckily many residential roads went through.