Recognizability and perceived urgency of bicycle bells

Raising awareness about how alarm sounds are perceived and evaluated by an individual in traffic scenery is important for developing new alarm designs, as well as for improving existing ones. Bearing a positive contribution to road safety, cyclists and pedestrians especially can benefit from appropriate alarming bell and horn sounds. Primarily, the alarm signal should evoke a precise idea of what is the source of the warning and the desired reaction to it. Furthermore, it should not be masked by other noises thus going undetected by the ear. Finally, an appropriate warning signal should transmit the urgency of a given situation, while at the same time, it should not cause other road users and pedestrians to startle. In two listening experiments, we examined the perception of commonly available bicycle bells and horns. Average typicality or recognizability as a bicycle bell among other everyday sounds has been investigated through a free identification task. In a second experiment, we tested perceived urgency of the warning sounds in relation to traffic noise. This article further provides a survey on non-verbal alarm design, as well as an analysis of acoustic properties of common bicycle bells and horns. Consequently, a linear regression model presents the relationship between named properties and perceived urgency. It is our intention to give an insight into the often unattended but important issue of the perception of auditory warning sounds in our everyday acoustic environment.