DCR requirements regarding roadways existing on top of dam embankments (4VAC50-20-45 and Guidance Document on Roadways on or Below Impounding Structures) appear to be both arbitrary and contradictory to federal and state roadway design criteria.  There are few, if any, roadways in Virginia designed to convey large storm events (PMF events) without overtopping, without the risk of failure during large storm events, without the risk of loss of life, or without the risk of economic damage.  Roadways on top of dams should be excluded from the Virginia impounding structure hazard potential classification process.