The roadside should be clear of all nonessential obstacles as determined by the state or county agency having jurisdiction. The area beyond the shoulder should be free of obstacles within a clear zone distance from the edge of the traveled way. Rounded ditch sections and flat side slopes which can be traversed by an out-of-control vehicle should be utilized. Ramps to stop runaway vehicles should be constructed whenever the terrain makes it necessary.
Haw. Code R. § 19-127.1-6