His son, Hirotake Arai (who succeeded his father in 1930), a keen motorcyclist, was approached to create a new design of sun-barrier caps for the growing Imperial Japanese Army, which was later involved in the 1934 invasion of China, the Second Sino-Japanese War, and World War II.

When Japanese construction industry unions made protective headwear compulsory, Arai produced safety helmets for construction workers, made from a resin outer shell lined with cork (which has since been substituted with expanded polystyrene).

He wore an industrial safety helmet when riding his motorcycle and established a new business, the Arai Hirotake Shoten Co. Ltd. After being awarded a Japanese Industrial Standards license in 1950, Arai began manufacturing and selling the first Japanese motorcycling helmets, designated H.A.

[1] Arai's helmets are hand-built,[7] with each fibre-reinforced plastic shell incorporating multiple reinforcing parts laid onto a round base (known as a "bird's nest").

[8] All Arai helmets sold in the US are made to meet or exceed Snell Memorial Foundation safety standards.

The Economic Commission for Europe (ECE) at the United Nations developed this testing for helmet safety, UN Regulation 22.

The standard mandated numerous tests in a whole host of areas: the shell, the strap, the visor, the field of vision, and so on.