Development of protocol to evaluate truck driver fatigue interventions

Author(s): Bronson Du, Hugh Davies, Pete Johnson, Phil Bigelow

Slidedeck Presentation Only (no paper submitted):

7B - Du


Truck drivers are vital to the economy as they deliver raw materials to manufacturers to make products and they also deliver finished products to retailers, distributors and wholesalers making it possible to be purchased by consumers.

Due to the long work hours and irregular work schedules, drivers are often fatigue which greatly increases the risk of road traffic accidents. It was found that about 20% of fatal accidents were related to sleepiness and it has been estimated that the cost of drowsy driving costs $12.4 billion per year in the United States.

Although, there are numerous interventions to prevent driver fatigue, there has not been an economical protocol that allows for a large scale epidemiological study on the effects of these interventions on driver alertness. The tools currently used require cameras to detect vigilance lapses which are much more expensive than using the mobile device being proposed.

Our objective is to develop an economical protocol to assess the effectiveness of driver fatigue interventions in the field setting.

1. A review of the literature on driver alertness measurements was conducted in search of validated measures of vigilance. The cost, sensitivity, test-retest reliability, and time requirement from the driver were considered. Potential effect modifiers were also reviewed for each one of the possible measures.
2. Experts in the field of transportation, and health and safety directors of truck fleets were consulted to discuss the feasibility of the use of each measurement tool in the field.

It was found that a 5-10 minute sustained reaction time task called the psychomotor vigilance task (PVT) was the most reliable, economical and feasible measure to be used in the field. A portable PVT testing portfolio had been developed and validated in the laboratory for the use in the field.

The protocol would require the driver to complete the 5-10 minute PVT immediately before starting on their route and immediately after along with a questionnaire on possible effect modifiers. The changes in PVT scores can be calculated to measure the decrements of vigilance over the work shift. If a fatigue intervention was effective, we would expect to see smaller decrements of the PVT scores.

This protocol has been shown to be sensitive to detect changes in drivers’ vigilance in a lab setting where drivers were placed in two conditions of different vibration-attenuating seats. The next phase of our investigation, which is currently underway, is to take this protocol into the field to evaluate the effectiveness of a reduction of whole-body vibration on truck drivers’ vigilance. We hope to present these findings at the conference as well.

A 15-25 minute protocol has been developed to evaluate the effectiveness of driver fatigue interventions such as the use of vibration-attenuating truck seats or implementation of a comprehensive Fatigue Management Program.