Toronto • May 28-29, 2010 • Student Day and Workshops: May 27
Paper: Assessment of discomfort and characterization of officer activity in police fleet vehicles
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Day/Time: Saturday at 14:00
Room: St. Patrick Room, 3rd Floor
Objectives:
Mobile police officers perform many of their daily duties within vehicles. Combined workspace inflexibility and prolonged driving exposure creates a risk for developing musculoskeletal issues. Given a lack of relevant research, it is difficult to justify specific interventions to improve the working situation until the physical and job demands are well understood. This two-phase study identified perceived musculoskeletal discomfort among a mobile police population, and characterized officer activity during a typical workday.
Methods:
Phase 1. Eighty-eight (88) officers completed two questionnaire packages, one at the beginning and one at the end of a 12-hour shift. Each package was designed to determine ratings of perceived discomfort related to specific automobile seat features, occupational equipment, job components and specific body regions. All discomfort ratings were reported using a 100 mm visual analog scale (VAS). Phase 2. Twenty-two (22) patrol officers volunteered for in-car video analysis of their activities. A laptop-based video collection system was assembled and mounted to the interior of one Ford Crown Victoria police cruiser in each of three different patrol districts. Officers were activity matched to one of a group of ten predetermined driver activities for each frame of digital video. Frame counts were used to calculate the percentage of time in each activity for the entire shift and percentage of in-car time in each activity (excluding time outside of vehicle).
Results:
Phase 1. Officer discomfort survey responses indicated high levels of discomfort (>30mm) as a result of various aspects of the driver seat and its low back support, due to use of the in-vehicle computer system, and specific to the lower back and surrounding body areas.
Phase 2. Out-of-vehicle officer activities were most prevalent, representing over 44% of a working shift. Driving activities showed the highest percentage time spent in an in-car activity posture occupying over 35% of in-car time. Mobile data terminal use was the most prevalent in-vehicle, non-driving activity, as it represented over 22% of in-vehicle activity time.
Conclusions:
A large amount of discomfort was associated with prolonged sitting and non-driving tasks performed within police vehicles. The driver seat was a specific area of concern, as high levels of low back were associated with the driver seat and wearing of the police duty belt. Mobile data terminal configuration and usage were identified as the primary sites for targeted design change, as MDT use elicited high levels of officer discomfort and is the most abundantly performed in-car, non-driving activity. Administrative, structural, and technological changes to seat design and the nature of police work must be made and evaluated from ergonomic, performance and safety stances to reduce both officer discomfort and injury prevalence.
