AMP: 0 Location: Mosby Rd and US-12, Musselshell Cty No reassurance shield as S-500 begins. AMP: 7 Location: Mosby Rd and Bridge Rd, Musselshell Cty A few miles up S-500, pavement ends. AMP: 9 Location: Melstone Rd and Ditch Rd, Petroleum Cty About halfway down S-500, we’re about halfway down S-500. AMP: 30 Location: Melstone Rd and MT-200, Petroleum … Continue reading Montana Secondary Highway 500, US-12 to MT-200