A handlebar bell is a civilized way to communicate with pedestrians. There's also the disadvantage of having to hear the horn yourself, plus the chance that the next time you apply for a job, your interviewers will recognize you as the person who assaulted them.
Life's like that sometimes.
Most of you have probably never heard the amazingly loud and shrill report of an original, old-time police whistle those heavy, brass beauties created in 1883 by the Birmingham, England, toolmaker and violinist, Joseph Hudson. At that time, the London police were searching for a noisemaker of some kind to replace their clunky hand rattles. Hudson developed a whistle that, when tested by the bobbies, was heard over a mile away. It was adopted immediately. Visa or MasterCard will put one around your neck, and I'd do it in an instant if I were a female commuter.