The Air Line Pilots Association (ALPA) has unveiled a new web site devoted to runway incursions. The world's largest pilots union, says these hazardous incidents happen more frequently than the public realizes, with about 2.5 incidents occurring in the United States per day. Sometimes collisions are narrowly avoided -- in one case, by just 35 feet. ALPA represents about 60,000 pilots for U.S. and Canadian airlines. Safety is an important part of its mission, and the interactive Web site supports that by highlighting where runway incursions occur most often and how pilots can increase their situational awareness to avoid them. ALPA’s “Hold Short for Runway Safety” Campaign is designed to raise the awareness of the measures that can prevent runway hazards through an interactive web site and a series of informative newsletters.