Why are all school buses yellow?

Trivia Contest

Win $25 gift card. Question: Why are all school buses yellow? If you know the answer, or want to take a guess, then email your answer to trivia@southeasternlaser.com.  Please provide your name, company name, phone number, email address. All correct answers will be entered in a drawing to win a $25 Southeastern Laser gift card, good toward any of our products or services. Rules: Deadline for your response is August 8, 2012. No peeking (Really?  You were going to Google it?) Only one entry per person. SE Laser employees and their families are not eligible. Valid only is states where not prohibited by law. No purchase required. It's only $25, are all these rules really necessary?   Submit to: trivia@southeasternlaser.com