Whole-body vibration exposure in metropolitan bus drivers

Area of Science:

• Occupational health and safety
• Biomechanics
• Transportation engineering

Background:

• Back injuries are prevalent among transit drivers, incurring significant costs.
• Whole-body vibration (WBV) is a known risk factor for drivers.
• New standards (ISO 2631-5) address impulsive WBV exposures, complementing existing ones (ISO 2631-1).

Purpose of the Study:

• To quantify bus driver WBV exposure using ISO 2631-1 and ISO 2631-5 standards.
• To compare WBV levels and seat transmissibility across different road types (freeway, city streets, speed humps).
• To assess differences in WBV exposure between buses and cars.

Main Methods:

• Thirteen bus drivers operated an instrumented bus over a 52 km route with varied road conditions.
• Whole-body vibration was measured at the seat and floor.
• A subset of five drivers also completed the route in a car for comparative analysis.

Main Results:

• Road type significantly impacted all vibration parameters.
• Continuous WBV (z-A(w)(8)) exceeded limits on freeways; impulsive WBV (z-VDV(8), S(ed)) exceeded limits in city streets and on speed humps.
• Bus WBV exposure was double that of cars, and bus seats amplified vibration.

Conclusions:

• Bus drivers face potential daily WBV exposure exceeding recommended limits, particularly on specific road types.
• The tested bus seats failed to attenuate vibration, potentially exacerbating exposure.
• Findings highlight the need for improved vehicle design and road maintenance to mitigate driver health risks.