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HighlightsMost of the experienced operators performed machine egress facing out from the cab.Egress was 2.5 s longer when facing in toward the machine, but no differences were observed in points of contact maintained when compared to egress facing out.Maintaining at least three points of contact during egress was observed for only approximately 30% of egress duration.A one-hour exposure to whole-body vibration did not change points of contact behavior nor egress duration when performing egress while facing out.Abstract. Mobile farm machinery operators are at a high risk of injury when entering (ingress) and exiting (egress) the cabs of such machinery due to slips and falls. Safety organizations and equipment manufacturers have delivered a consistent message: operators are to egress machines facing in, toward the access path, and maintain three points of contact at all times. This study used a laboratory-based model of a mid-sized agricultural tractor to determine adherence to best practices for safety and the effect of acute whole-body vibration exposure on compliance. The majority of 19 experienced operators (16 male, 3 female) performed machinery egress facing out from the cab because descending while facing in toward the machine took 2.5 s longer. Maintaining at least three points of contact during egress was observed for only approximately 30% of egress duration, but was as high as approximately 41% for participants who self-selected the facing-in orientation. Exposure to 1 h of whole-body vibration did not change points of contact behavior nor trial duration when performing egress while facing out. Overall, the model cab used in this study had safety features similar to a real-world machine, indicating that there may be opportunities in access path or cab door design to promote increased points of contact use. Future work is needed to accurately assess three-dimensional movement patterns and external forces for disease and injury risk models. Keywords: Access path, Farm machinery, Safety guidelines, Occupational injury.

Drivers inadequate mental workload has been reported as one of the nega- tive effects of driving assistant systems and in-vehicle automation. The increasing trend of automation in agricultural vehicles raises some concerns about drivers mental work- load in such vehicles. Thus, a human factors perspective is needed to identify the conse- quences of such automated systems. In this simulator study, the effects of vehicle steering task automation (VSTA) and implement control and monitoring task automation (ICMTA) were investigated using a tractor-air seeder system as a case study. Two performance parameters (reaction time and accuracy of actions) were measured to assess drivers perceived mental workload. Experiments were conducted using the tractor driving simu- lator (TDS) located in the Agricultural Ergonomics Laboratory at the University of Manitoba. Study participants were university students with tractor driving experience. According to the results, reaction time and number of errors made by drivers both de- creased as the automation level increased. Correlations were found among performance parameters and subjective mental workload reported by the drivers.

The goal of this study was to assess the sensitivity of the heart rate variability measure to variations in task difficulty and drivers' mental workload in agricultural semi-autonomous vehicles. 30 young participants with at least one year of tractor driving experience performed steering and implement control and monitoring tasks in a simulator study. Experiments were conducted using the tractor driving simulator (TDS) located in the Agricultural Ergonomics Laboratory at the University of Manitoba. Five levels of automation support from low to high were defined for the implement control and monitoring task. One-half of the participants performed a manual steering task while the other half drove the TDS in automatic steering mode, which only required them to monitor a mapping system and supervise the computer that was performing the steering task. A heart rate monitor was used to record the participants' heart rate. Time and frequency domain parameters of heart rate were analyzed. Some of the time and frequency domain parameters showed some sensitivity to workload variations, however, inconsistencies were observed in the results. The widely used HRV parameter, 0.1 Hz component of HRV, was not sensitive enough to differentiate mental workload levels when the drivers were involved in the task-loop.

The effects of in-vehicle automation and driving assistant systems on the situation awareness of drivers have been the subject of much research with the implications of automation in such man-machine systems being identified. With the introduction of advanced automated systems in agricultural machinery, farmers are now working with semi-autonomous vehicles. A human factors perspective is needed to ensure the safe and efficient operation of such systems. This simulator study investigated the effects of automating vehicle steering and implement control and monitoring task automation on the situation awareness of drivers. Experiments were conducted using a tractor driving simulator located in the Agricultural Ergonomics Laboratory at the University of Manitoba. Thirty young, experienced tractor drivers participated in this study. It was found that implement control and monitoring task automation significantly affected the situation awareness of operators. Situation awareness increased as the level of automation support increased although the highest level of automation, where the participants were removed from the task loop, resulted in low situation awareness at a level similar to the condition with no automation support. The highest level of situation awareness was observed when the simulator suggested the required action to be taken by the operator. Vehicle steering task automation reduced the attentional demand of the task.

Drivers’ mental workload when using driving assistant systems and in-vehicle automation has been the subject of many studies in recent years. Drivers of semi-autonomous agricultural vehicles are experiencing an increasing number of automated systems. Due to implications of automation support on the operators’ performance, a human factors perspective is needed to identify the consequences of such automated systems. In this simulator study, the effects of vehicle steering and implement monitoring and control automation were investigated using a tractor air-seeder system as a case study. Experiments were conducted using the tractor air-seeder driving simulator (TAS-DS) located in the Agricultural Ergonomics Laboratory at the University of Manitoba. Study participants were university students with tractor driving experience. Based on the results from the experiment, most of the automation conditions impose moderate levels of mental workload on operators. Implement monitoring and control automation show significant effect on the drivers’ mental workload, contrary to the steering automation.