TRB's Airport Cooperative Research Program (ACRP) Report 3: Analysis of Aircraft Overruns and Undershoots for Runway Safety Areas explores overrun and undershoot accident and incident data conditions relating to these occurrences. The report also includes an assessment of risk in relation to the runway safety area and highlights a set of alternatives to the traditional runway safety area. The appendices to ACRP Report 3 are available online. ACRP Report 50: Improved Models for Risk Assessment of Runway Safety Areas, which was released in July 2011, expands on the researc presented in ACRP Report 3. ACRP Report 50 analyses aircraft veer-offs, the use of declared distances, the implementation of the Engineered Material Arresting System, and the incorporation of a risk approach for consideration of obstacles in or in the vicinity of the runway safety area. View the Impact on Practice related to this report.