Toyota Motor Corp said Tuesday (September 30) that it has developed world's first airbag to protect rear passengers' heads in the event of a read-end collision.

The company calls it the SRS (supplemental restraint system) rear window curtain shield airbag. It deploys from the roof lining above the rear window in the form of a curtainlike barrier.

The airbag, together with the headrests, helps reduce the severity of injuries by minimising the impact to the head from a colliding vehicle or parts of the hit vehicle, Toyota said.

Its use in the iQ ultracompact four-seater, which is due to be launched soon, is expected to approximately double the car's rear passenger head protection performance, the company said.