Historical Highway Markers By Dr. Leif Tapanila & Peter Pruett Published January 11, 2024 at 6:00 AM MST Listen • 29:57 For this episode of The Nature of Idaho, join hosts Dr. Leif Tapanila and Peter Pruett as they discuss road signs with former Idaho State Historian Keith Peterson. Trivia Question: When did the Historical Highway Markers start in Idaho?Trivia Answer: The 1950s