The AASHTO Manual for Assessing Safety Hardware (MASH) is the new state of the practice for the crash testing of safety hardware devices for use on the National Highway System (NHS). It updates and replaces NCHRP Report 350.

MASH presents uniform guidelines for crash testing permanent and temporary highway safety features and recommends evaluation criteria to assess test results. This manual is recommended for highway design engineers, bridge engineers, safety engineers, researchers, hardware developers, crash test laboratories, and others concerned with safety features used in the highway environment.

The implementation of the AASHTO Manual for Assessing Safety Hardware (MASH) by State DOTs will necessitate the examination and evaluation of roadside safety hardware currently being used by the State DOTs. It is already known that some currently used roadside safety hardware will not meet MASH requirements.