Roadside Hazard

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Roadside Hazard

Roadside Features  and roadside hazards are synonomous in RSAP. Roadside hazards include anything outside the travelled way which may influence the crash potential of an errant vehicle. Items range in scope from the roadside hardware specifically designed for placement on the roadside (i.e., guardrail, guardrail terminals, crash cushions, etc.) to trees and other naturally occurring hazards. Other objects such as utility poles, signs and mailboxes can be positioned on the roadside. RSAPv3 also includes a number of new "special edges" like the edge of the median to detect median cross-overs, the edge of a water body, as well as the clear zone edge.



Default hazard severities have been provided with RSAPv3 for roadside hazards and are shown of the Severity Worksheet. The RSAPv3 Engineer's Manual contains a detailed discussion on the development of these severities and provides instructions to collect data and develop severities for new hazards or for hazards using regional data. The severity information may be viewed by selecting the "Hazard" button on the RSAP Controls Dialog, but the values cannot be changed in the Severity Worksheet. Instructions for adding or editing hazard information in the Severity Worksheet Scribble16 are in the Engineer's Manual.



Roadside hazards are located using the baseline Station and Offset Scribble203 method. Recall, the Offset is measured from the center of the hazard perpendicular to the baseline and the direction of Offset (i.e., Left or Right of the baseline) is specified. Hazards which have an associated length (e.g., longitudinal barrier) should be entered using the beginning and end Stations and Offsets. Point hazards (e.g., trees, poles, signs, etc.) should be entered using a single Station and Offset and the hazard diameter.



Point hazards include trees, poles, bollards, the ends of guardrail terminals, and other fixed objects which do not have an area or length but which can be represented as a point in space. Line hazards include longitudinal barriers, the edge of a clear zone, the edge of a median, and any other objects which can be represented as a simple line.



The Alternatives Worksheet Scribble40 has hazard sensitive menus which aid in data entry for the seemingly endless set of roadside hazards which an errant vehicle may encounter when it leaves the road. This large range of hazards can be grouped first into a General Hazard Type, then a Specific Hazard Type.