I often wondered about the legality of lane splitting in Idaho as the motorcycle riders manual issued by the State of Idaho states only to "discourage others from lane splitting." It looks like others have wondered the same thing and someone wrote a letter to KTVB news asking about it. KTVB contacted the Idaho State Police who confirmed that lane splitting is, indeed, illegal in Idaho. May 25, 2006 http://www.ktvb.com/news/special2/stories/ktvnz-may2506-wizard.200f9018.html Dear Road Wizard: I have read Idaho's Motorcycle Operator's Manual and cannot find where it says that lane splitting is illegal. Can you clarify: is lane splitting lawful or unlawful in Idaho? B.P.@ For those who drive in "cages" and don't know, lane splitting, also called "lane-sharing" and "white lining," is the practice of driving one's motorcycle between two lanes of traffic along the white skip-stripe separating the lanes. It's a way to make progress when traffic has reached crawl or stall conditions. Space between the idling cars beckons the cyclist forward to help reduce total congestion by one machine. Lane splitting is allowed in California under certain conditions. Elsewhere, its legal status is negative or ambiguous, prompting motorcyclists to organize and make it legal. The Idaho manual ( http://itd.idaho.gov/dmv/driverservices/ds.htm) is based on text produced by the national Motorcycle Safety Foundation. Idaho publishes it, but hasn't customized the section on lane splitting (page 17). It offers generic cautions, such as "Cars and motorcycles need a full lane to operate safely" and "Discourage lane sharing by others." The Idaho State Police say, "We consider lane splitting illegal." Boom. Not ambiguous. They cite Idaho Code 49-637, which says, "A vehicle shall be driven as nearly as practicable entirely within a single lane..." If an officer sees the cyclist as "reckless," that citation is available, too.