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Federal Highway Administration Research and Technology
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This report is an archived publication and may contain dated technical, contact, and link information
Publication Number: FHWA-HRT-11-024
Date: April 2011

Safety Evaluation of the Safety Edge Treatment

Appendix A. Identification of Drop-Off-Related Crashes

All crashes obtained from participating agencies were screened, and crashes that were not relevant to the study were excluded. All remaining crashes were then classified into whether one or more of the involved vehicles ran off the road. Then, each run-off-road crash was classified as to whether it was potentially related to a pavement-edge drop-off. Differences in accident reporting between agencies led to individualized classification criteria for each agency. The classification criteria and data elements used for each agency are described in table 38.

Table 38. Classification criteria for crashes.




New York

Excluded crashes

Intersection and intersection-related

Intersection and intersection-related

Intersection and intersection-related
Non-reportable crashes and non-injury crashes (with less than $1,000 in property damage to any vehicle) since these crashes were not available for all years

Run-off-road crashes

If harmful event included a roadside object
If location of impact was off the roadway

If any vehicle collided with a roadside object
If manner of collision was ran-off-road
f primary factor was ran-off-road right or ran-off-road left

If accident type involved a roadside object
If location of first harmful event was off the roadway
Ff second event for any vehicle involved a roadside object

Drop-off-related crashes

If crash road type was defective shoulders or "holes, deep ruts, bumps"
If driver contributing factor indicated driver lost control

If primary factor was overcorrecting/over‑steering

If contributing factor for any involved vehicle was defective shoulder

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