Investigating the Effects of Earcon and Speech Variables on Hybrid Auditory Alerts at Rail Crossings

Despite rail industry advances in reducing accidents at Highway Rail Grade Crossings (HRGCs), train-vehicle collisions continue to happen. The use of auditory displays has been suggested as a countermeasure to improve driver behavior at HRGCs, with prior research recommending the use of hybrid sound alerts consisting of earcons and speech messages. In this study, we sought to further investigate the effect of auditory variables in hybrid sound alerts. Nine participants were recruited and instructed to evaluate 18 variations of a hybrid In-Vehicle Auditory Alert (IVAA) along 11 subjective ratings. Results showed that earcon speed and pitch contour design can change user perception of the hybrid IVAA. Results further indicated the influence of speech gender and other semantic variables on user assessment of HRGC IVAAs. Findings of the current study can also inform and instruct the design of appropriate hybrid IVAAs for HRGCs.