Well, it is not like Big Brother is using video surveillance, to monitor and enforce three feet of clearance, but if a motorist actually hits a cyclist, it is a lot easier to show negligence if the motorist was supposed to leave three feet of clearance. In my area, it is a "no harm, no foul" situation; if a cyclist is not actually hit, the motorist has left enough room, even if it was a mere millimeter, and the motorist veered toward the cyclist intentionally. "Buzzing" is largely legal in areas without a minimum-clearance standard.
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