
It started with driver-side airbags, quickly progressed to dual airbags catering for the driver and front-seat passenger, then to side-impact airbags initially for the front seats but then becoming available for the rear seats also.
Then followed head-height curtain airbags running the full length of the passenger compartment; knee airbags for the driver and, shortly afterwards, for the front-seat passenger as well.
Now Mercedes-Benz and Toyota are adding further to the tally of explosively inflated passenger protection devices: Mercedes with additional hip-height bags for front-seat passengers in the next generation E-Class, and Toyota, which has developed a bag that pops out from the top of a centre console to stop rear-seat passengers from colliding with each other in a side impact.
Toyota says its new system is designed not only to protect rear-seat passengers from each other, but also to help lessen the chances of injury inflicted by the centre console itself.
The head-thorax bag is presumably only activated when both rear seats are occupied and the system is clearly not suitable for anything other than a two-passenger rear seat.
Toyota says the new system will appear in a "model to be released in the near future."
As there aren't too many Toyotas available in Australia with just two rear seats, and assuming the technology will arrive initially in upper echelon models, speculation about when rear-centre airbags will come to Australia remains wide open.