A breakaway guardrail post includes upper and lower post sections spaced apart but connected by a breakaway joint. The joint is attached at one end to the upper post by a first fastener set and connected at a second end by a second fastener set. The first fastener set has a failure strength less than that of the second fastener set. Upon impact forces being applied to the upper post section, the first fastener fails and the upper post section rotates downwardly.