Mental Fatigue Impacts Worker Hazard Detection

mental fatigue

For organisations that have workers operating heavy mobile equipment, their level of mental fatigue and its impact on hazard detection is critical. Heavy mobile equipment is used daily on construction, mining and infrastructure sites. Machine operators spend significant hours behind the wheel.

Does the length of time operating mobile equipment each day affect their hazard detection ability?

For this article, we look at research published this year that measured the level of mental fatigue of construction workers operating heavy mobile equipment using wearable eye trackers. The study tracked fatigue levels and compared them to the workers’ hazard detection skills.

The findings clearly show that the more mentally fatigued a worker is, the less their ability to detect hazards in their workplace. Fatigued workers have a slower reaction time and fail to see obvious workplace hazards.

Where workers are required to dedicate whole shifts to operating mobile equipment, additional safety interventions must be in place, including hazard perception training to overcome fatigue-related errors and failures in hazard detection.

Heavy Mobile Equipment Hazards

Heavy mobile equipment is in daily use on construction, mining and infrastructure sites. Examples of equipment include the use of excavators, loaders, graders, cranes and trucks. This equipment is heavy, hard to manoeuvre and slow to stop. Operators of such equipment must hold a valid heavy vehicle driver’s license.

The most common accidents on construction sites, for example, are as a result of workers coming into contact with heavy mobile equipment.  Operating heavy mobile equipment is highly hazardous in that every piece of machinery has blind spots and vision shadows that the operator cannot see.

However, the lack of attention or failures in concentration by equipment operators are also reasons for workplace injuries in these industries.

Operating heavy mobile equipment requires the operator to focus on the areas in front, behind and around the machine, the control panel of the machine, other equipment operating in the area and workers on foot. The operator must shift their vision constantly.

The continual changes to where they are looking make workers operating heavy mobile equipment more mentally fatigued than others.

Mental fatigue, caused by these continuous operating and monitoring activities, affects the operators’ level of concentration and hazard detection ability. As fatigue sets in, workers fail to see obvious hazards.

See our article, Can Employees Recognise, Recall and Report Workplace Hazards?

Mental Fatigue Levels Affect Hazard Detection

The study found that the more tired the operator became, the less likely they were to look in their rear vision mirror or around them. After 1 hour operating the machine, the operators had an increase in their hazard miss rate, false alarm rate, and reaction time by over 40%.  After only 36 minutes operating the machine, their ability to detect hazards dropped by 30% compared to what they found when they first sat down.

These results show that after half an hour of operating heavy mobile equipment, workers are only noticing 70% of the hazards around them. 

While operating equipment, mental fatigue makes workers reluctant to pay more attention to the ‘edges’ of their direct vision. After 36 minutes, they begin to look at only what is directly in front of them.

They fail to look in their rear vision mirrors or to the sides of the machine because these actions require additional head movements. Operators are reluctant to use the extra effort to scan the whole of their surroundings. Mental fatigue makes it difficult for operators to detect potential peripheral hazards in a timely manner.

When operators experience mental fatigue, they are more likely to quickly glance at their surroundings, rather than directly observe the hazards surrounding their equipment. This behaviour can lead to missing hazards and a decrease in response times to risks of collision or rolling.

See our article, Top Workplace Hazards in the Construction Industry.

Strategies to Reduce Mental Fatigue and Increase Concentration

There are several strategies that employers can use to ensure operators of heavy mobile equipment manage their mental fatigue to improve their concentration and hazard detection.

  1. Increase the level of supervision after the 30-minute mark of machine operation.
  2. Provide regular breaks from machine operation for operators.
  3. Use wearables that detect and alert about lowering levels of concentration (e.g. eye-trackers).
  4. Manage work shifts that take into account the complexity of the surrounding environment.
  5. Ensure the safe separation of heavy mobile equipment and workers on foot using exclusion zones, barricades and signage.
  6. Provide hazard perception training that focuses on heavy mobile plant.

Tap into Safety Hazard Perception Training for Mobile Equipment

The underpinning knowledge of how to work safely while operating heavy mobile equipment starts with effective training. Proactive hazard perception learning activities embed knowledge and significantly reduce workplace incidents and injuries.

Tap into Safety has out of the box safety training courses to address mobile equipment hazards using an interactive methodology and 360-degree immersive scenes.

  1. People and Plant  on a Construction Site
  2. Road Works
  3. Road Construction
  4. Traffic Management
  5. Maintenance Workshop
  6. Mining Maintenance Workshop
  7. Road Work Plant Exclusion Zones
  8. Excavations
  9. Mobile Cranes

  10. Transport Chain of Responsibility

Supporting ongoing training to refresh and remind critical hazards when operating mobile equipment there are also several microlearning courses available on the platform, including Access Egress Barrier Selection, Blind Spots and Vision Shadows, Heavy Vehicle Solo Driver Fatigue Management and Fatigue Management.

Contact Us for more information or try a free demo.

To Conclude

For companies working with heavy mobile equipment issues of operator mental fatigue and hazard detection should be front of mind. Concentration levels begin to decline after 30 minutes of operating a machine.

Additional safety interventions must be in place, including increasing supervision, taking regular breaks and providing hazard perception training to overcome fatigue-related errors and failures in hazard detection.

It is also crucial in the planning and management of a site to recognise the complexity of the job. Critically, you need to establish and monitor exclusion zones around heavy mobile plant and workers on foot.

After all, there are recognised blind spots and vision shadows on all heavy mobile equipment. Importantly, this study found that operators tend to favour only looking in front of them when mental fatigue increases.

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