Motorcycles fitted with different designs of leg-protector and carrying a dummy rider were crash tested into a wood-faced metal barrier, angled at 60° and 30° to the direction of impact. At 60° the crash mechanism resembled that of a 90° impact but at 30° the mechanism corresponded to the type reported to cause most of the serious leg injuries and therefore this angle was chosen for all the remaining tests.

The trajectory of the motorcycle and dummy rider was analysed in detail from high-speed film taken for each test. The potential leg injuries were assessed by the use of a novel injury-indicating leg constructed partly from aluminium honeycomb, the damage to which is an indication of the energy impacted to the leg. This energy is compared with that reported to be required to break human leg bones.

The results from tests with non energy-absorbing and energy-absorbing protectors on 175 c.c. machines are compared with those from a similar and unmodified machine. A particular design of energy-absorbing protector not only effected a reduction of about 75% in the energy impacted into the leg but was also shown to cause a significant reduction in the dummy head velocity at two critical planes in the impact.

This design suitably modified was tested on both a large (B.M.W. R80) and a small motorcycle (Yamaha 90) and shown to have similar advantages compared with a corresponding unmodified machine.

Performance criteria for leg protectors are specified to conclude this research. The motorcycle launch method is also described in detail.