Laws with sharp turns on gravel roads?

Someone I knew died off exit 5A off the 103 on Tuesday morning.

The police report said it happened at “the end” of the “gravel” road against some “boulders.”

I went and looked and it happened at the START of the road right before it became gravel and while there were boulders around there were no boulders at the crash site just a ditch and a muddy embankment.

Several people told me boulders on sharp corners were legally mandated so it wasn’t legal for this corner to be without but someone else told me to back off and let the police do their work.

I know I’m probably being too much I’m so sorry. I just want to hear the legalities of the situation and get other people’s experiences to also make me feel better because I am honestly devastated.