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Roadside Features 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 on 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, but the values cannot be changed in the Severity Worksheet. Instructions for adding or editing hazard information in the SEVERITY worksheet are in the Engineer's Manual.
The Severity Worksheet is a database of hazard severities that is used by RSAP. Normally, the user should not modify these values but there are instructions for adding, deleting and editing these values in the Engineer's Manual if it is necessary. Each row represents the data that describes the severity model for one type of hazard. The columns are:
· Hazard Name - This is the name of the hazard and is used to uniquely identify the hazard.
· Annual Maintenance Cost - This is the normal maintenance cost associated with the hazard. Many times the annual maintenance cost will be zero but for some types of features there is a typical cost of maintaining the system. Maintenance cost is NOT the same as repair cost. The maintenance cost should only reflect the cost of maintaining a feature and not any repair due to crashes.
· Typical Repair Cost/Crash - This is the typical cost for repairing the feature after a crash. For example, a collision with a type of guardrail may on average cost $1000 to repair after each crash. The cost is an average, obviously some crashes will be more costly than others and some less.
· EFCCR65 - This is the equivalent fatal crash cost ratio at a reference speed of 65 mi/hr. The EFCCR is the basic value used to assess the severity of crashes. Informaton about how the EFCCR's were developed and implemented is available in the Engineer's Manual. EFCCR values range from zero to 1. The tabulated EFCCR is the typical severity of a crash with this particular object at a speed of 65 mi/hr. RSAP scales the EFCCR up and down depending on the actual speed predicted in the collision module of the program.
· Penetration/Rollover/Vault -- this is the percentage of vehicles on average that penetrate, rollover the feature or vault over the feature.
· Redirection Rollover -- this is the percentage of vehicles that on average rollover after interacting with the feature.
· Capacity -- this is the theoretical impact capacity of the feature in ft-lbs.
· Barrier Height -- for longitudinal barriers this is the distance from the ground to the top of the barrier. The value is only used for longitudinal barriers.
· Speed Adjust EFCCR -- as described earlier, most EFCCR's are adjusted from the tabulated value up or down to the actual estimated impact speed. There are some hazards where this is not appropriate. For example, if a vehicle crosses into the opposing lanes (i.e., crosses the median edge special edge) the EFCCR does not depend on the speed, just that the vehicle crossed the line.
· Category -- this is the General Hazard Type associated with this feature.
· Comment/Reference -- this field is for notes and references and is not used by RSAP.
There are four buttons available on the Hazards tab in the RSAP Controls Dialog:
· Alphabetical -- arranges the list of Roadside Hazards in alphabetical order.
· Category -- arranges the list of Roadside Hazards in order of their category and then alphabetically within the category.
· Severity -- arranges the list of Roadside Hazards in order of increasing EFCCR65.
· Capacity -- arranges the list of Roadside Hazards in order of increasing capacity.