This study is to find out how Visual range and distance can give an positive that effect ensures safety at work site, varying the colours of workers safety vest at a construction sites. HSE clarifies what colour showed be applied at work site, but It may be doubted that this rule will be appropriate for them to perform new, too. The relevant regulations came into effect made long time ago, without a suitable change to relent trend the and recognition of the visibility of various colours.. These will be tested, at a site, with the main colours, applied in experiments, for the study.