An approach to assessing human factors related occupational safety using behavioural observation-based indicators: the case of a construction site in nigeria
Globally, the construction industry is regarded as one of the most dangerous where workers often face safety and health risks throughout
the process of task and activities execution. Safety violations through unsafe behaviours are major contributors to these risks. This
research aimed to develop a quantitative model that assesses the level of workers"e safety on a construction site based on behavioural
observation. A construction firm in Southwest Nigeria was identified and studied. Data on tasks performed by the workers on the
number of unsafe behaviours (𝑁) and the durations in which they lasted (𝐷) was collected. Based on this, the level of safety adherence
(LSA), the initiated and sustained number of safety violations (I-NSV and S-NSV) and the probability of unsafe acts occurrence and
zero unsafe acts (PUA1 and PUA2) indicators were developed and used in assessing the safety level of the project. An evaluation of
different levels of 𝑁 and 𝐷 was also undertaken to provide further insight into the requirements for attaining an improved systems
safety level. The results obtained indicated that the LSA was 0.35. The I-NSV and S-NSV results were 41 and 118 unsafe acts
respectively while the PUA1 and PUA2 values were 1.00 and 0.00 respectively. Evaluation results showed that LSA increases were
directly related to S-NSV decreases caused by corresponding decreases in 𝐷, while improved project safety levels could be achieved
through I-NSV mitigation. The study concluded that the safety level of the construction site was low and recommended improved
safety strategy implementation for attaining improved project safety level. The model is useful for measuring construction projects"e
safety levels based on workers"e safety violations and the study outcome could be used to set improvement targets and relay feedback
for safety behaviour improvement in construction firms and related organisations.