In my years of work, I've spent many a long hour standing at a flag post directing traffic. It's a long hard day of standing, hoping you don't get hit by a distracted drive, jumping to keep from being hit by a distracted driver, wondering when you'll get a break to go pee, wondering if you'll have time to sit in the shade and eat lunch and the hope it doesn't start raining. Slick highways, and poor visibility, raises the whole danger thing a notch.
In the past, the flagger didn't have any training. Now, they have training, certificates of their training and are expected to behave in a professional manner. It's important and necessary, but it still doesn't prevent accidents.
This morning was the last day on a job for a flagger. I don't know the details, but I do know the contractor and probably met some of the people involved - maybe even the flagger. They were struck and killed at 8:00 am this morning. I hope they didn't suffer and I pray for their family.