N.J.R.S. §39:3-69 mandates that motor vehicles be equipped with a working horn to warn other drivers, so a motorist who fails to warn others for lack of a working horn could be held liable for causing a collision with a cyclist who was unaware of his or her presence. While a cyclist is prohibited from installing a horn, whistle, or siren on his or her bike, N.J.R.S. §39:4-11 states that a biker must have a bell or similar audible signal attached to his or her bicycle.
Additionally, N.J.R.S. §39:4-10 requires bicyclists to have proper lights and reflectors to make their presence known to drivers and others on the road.