What happened to SAFETY FIRST?

In my years working in construction sites, waste treatment and petchem chem plants, SAFETY was always paramount. Safety helmets, vests, harness, boots, coveralls, glasses or goggles etc were the norm. SAFETY FIRST was the motto. But it seems that safety is not always highly regarded by others. Many a times, I would see workers working on a road in the dead of night with no high-visibility safety vests. Is it nonchalant attitude towards their own safety, ignorance or employer non-diligence?