The AASHTO Manual for Assessing Safety Hardware (MASH) specification presents uniform guidelines for the crash testing of both permanent and temporary highway safety barriers and recommended evaluation criteria to assess test results. MASH guidelines and criteria, which have evolved over the past 40 years, incorporate current technology and the collective judgment and expertise of professionals in the field of roadside safety design. They provide:
(1) a basis on which researchers and road agencies can compare the impact performance various safety barrier systems,
(2) guidance for developers of new safety barrier systems, and
(3) a basis on which road agencies can formulate performance specifications for safety barrier systems.
MASH is also the basis of testing procedures for road safety systems as stated in AS/NZS 3845.1: 2015 Road Safety Barrier Systems and Devices. The introduction of MASH follows changes to the vehicle fleet, researching of real-life impact conditions and updated criteria for evaluating barrier performance.
The underlying philosophy in the development of the MASH guidelines is that of “worst practical conditions.” The crash test parameters, such as the test vehicle, impact speed and angle combination, point of impact, test matrix, etc., specifies the worst, or most critical, conditions.
