An array of vigorous testing is performed to determine how well a helmet would hold up in the event of a crash, the tests to measure a helmets safety are Penetration, Impact Attenuation and Retention.

Penetration: When this test takes place, a test striker (an anvil) is dropped onto the helmet from a fixed height, the striker cannot penetrate though the helmet to the test head form (your skull).

Impact Attenuation: Basically means energy absorption, how well the helmet displaces the energy of an impact.

Retention: This tests the effectiveness of the helmets ability to stay on your head during a crash, the Helmets retention system (chin strap and D rings).

To meet Australian standards a helmet needs to pass the Snell rating as a minimum, if your helmet only carries a DOT rating then it will not be accepted as adequate at any Australian competition and you may be refused entry to the track. If you find a helmet with all three ratings then you are onto a good thing as not only has the manufacturer gone to the trouble to have it tested by all three organisations, it has also passed them all making it pretty hard to beat!