Idaho stop
n. Stop sign behavior where a vehicle, particularly a bicycle, slows down but does not come to a complete stop.
Here's an idea that would light up talk-radio phone lines, even though it would do little more than legalize what many cyclists do every day anyway: It's called the Idaho Stop. …

Almost no cyclist, even the most cautious, stops at stop signs in this city. Dr. Gridlock has previously smugly bragged that he does. But, in fact, he does not. He does Idaho stops.
—Jeff Gray, “Idaho Stop one way to fuel 'war on the car',” The Globe and Mail, May 29, 2009
The laws of physics make it awkward for a bicyclist to come to a complete stop — forward momentum is what allows a two-wheeled vehicle to maintain balance. It's understandable that bicyclists would want to be permitted to glide through stop signs if no other traffic is approaching.

That's what House Bill 2690 would allow: an "Idaho stop" — which is no stop at all, named for the state where bicyclists are allowed to treat stop signs as yield signs.
—“'Stop' means stop,” The Register-Guard, April 25, 2009
2000 (earliest)
Among the suggestions to the Legislature's Interim Transportation Committee are adoption of the "Idaho stop rule" allowing cyclists to yield rather than stop at stop signs, and an end to the requirement that cyclists ride on a sidewalk or path if one is provided beside the road.
—Brandon Loomis, “Committee Charts Bike-Friendly Path,” Salt Lake Tribune, May 28, 2000
Why Idaho? That U.S. state has had a law since 1982 that allows cyclists to treat stop signs more or less as yield signs. That is, they don't have to come to a complete stop, but they do have to yield right-of-way to pedestrians and other vehicles.