The mystery of the 17 cross cluster of Montana...

The State of Montana, through the American Legion, posts white crosses as locations where road fatalities have occurred.  They are erected along roads, other than the interstates (which have limited access and no private frontage along the roadway).  A deceased's survivors can decline not to have a cross, it rarely happens, but such requests are honored.  While family members may treat them as roadside memorials, they are intended as a safety warning.

Here is an especially sobering one from Montana's U.S. Route 2:

The 17 crosses of Montana's Route 2 explained...

Little Black Star explains:  One way to tell if you’re on a Montana road is that they mark their highway fatalities with white crosses. Each cross represents one fatality. They’re placed in the “exact” spot where they died (or where they were hit before being taken to the hospital where they died). It’s kind of creepy...