Critical evaluation of the SHARP motorcycle helmet rating

The Department for Transport introduced a safety helmet assessment and rating program (SHARP) for motorcycle helmets sold in the UK. The mechanics behind the part of the scheme that uses a rigidsphere head-plus-helmet model to estimate the peak headform acceleration in oblique helmet impact tests, is assessed and the approximations exposed. Finite Element Analysis, of a deformable helmet with a realistic shape, is used for comparison. The statistical analysis of motorcyclists’ impact velocities, sites and impact type, used to weight the SHARP impact results, is also reviewed. Conclusions are reached on the meaning of the derived oblique impact test results, and validity of the star rating.