Measurements of the at-ear helmet-generated aerodynamic noise and helmet transmission loss were carried out for the two major types of motorcycle helmets. From this data and existing information on noise generation by flow around a bare head it was found that for quiet motorcycles at typical speeds the majority of the riders at-ear noise is generated by the air flow. An assessment of the possibility of hearing damage was then carried out. It was found that only with extremely high usage would there be a significant risk of hearing damage for either the bare-headed or helmeted rider. Helmets did, however, give significant protection. Detection of warning signals was then considered. It was found that under no conditions did the helmet put its wearer at a disadvantage to the bare-headed rider and at typical speeds the helmet gives a considerable advantage in the detection of warning signals.
Abstract