"Idaho's rule is pretty straightforward," writes Joseph Stromberg, "[if] a cyclist approaches a stop sign, he or she needs to slow down and look for traffic. If there's already a pedestrian, car, or another bike there, then the other vehicle has the right of way. If there's no traffic, however, the cyclist can slowly proceed. Basically, for bikers, a stop sign is a yield sign." Additonally, bikers approaching a red light must stop, but if there is no oncoming traffic, the biker can treat the light as a stop sign, and proceed through the intersection.
After acknowledging that the Idaho Stop has not been adopted by many other locations—as well as detailing the simple physics problem that compels many bikers to choose not to stop—Stromberg goes on to examine research suggesting that the Idaho Stop is not any less safe than the more common alternative: "Public health researcher Jason Meggs found that after Idaho started allowing bikers to do this in 1982, injuries resulting from bicycle accidents dropped. When he compared recent census data from Boise to Bakersfield and Sacramento, California — relatively similar-sized cities with comparable percentages of bikers, topographies, precipitation patterns, and street layouts — he found that Sacramento had 30.5 percent more accidents per bike commuter and Bakersfield had 150 percent more."
Stromberg also makes a couple additional, less scientific, arguments in favor of allowing Idaho Stops.