Effects of Speech Intelligibility among Bradley Fighting Vehicle Crew Members: Simnet Performance and Subjective Workload

Abstract

Speech communication among crew members in military vehicles suffers from several sources which interfere with speech intelligibility. The effects of intelligibility were studied in the SIMNET Training facility at Ft. Benning, G.A. Twelve Bradley-qualified, three-man crews were tested on a series of navigation and gunnery exercises. A repeated measures design was used to test five levels (0%, 25%, 50%, 75%, and 100%) of speech intelligibility. In each 10–minute exercise, the Commander used a map and mission statements to direct his crew on a 1.5 to 2.0 km course. Four check points had to be reached and one or three target vehicles destroyed. Subjective Workload Assessment Technique (SWAT) measurements were taken after each exercise. The level of speech intelligibility affected mission success and SWAT results. The impact of intelligibility was found even at the first drop in speech intelligibility (100% to 75%). We concluded that performance and operational success are adversely affected by poor speech communication. Remedial measures to radios, headsets, vehicular insulation, and hearing protection can improve speech intelligibility in these vehicles and, hence, improve performance.