This paper presents the results of a series of thorax loading tests, in which the aim was to analyze the response of human surrogates in an inline frontal impact when restrained by a diagonal seatbelt. The general results of 33 tests on 20 cadavers and 42 tests on 2 different Hybrid III dummies are reported. The tests show that the energy required to fracture 6 ribs is lower than previously reported at 417 joules. They also show that the Hybrid III is twice as stiff as the cadavers tested in this mode of thorax compression.