Toyota is working on a new system called Quick Active Seat (QAS) that will enhance the world-first Rear Pre-Crash Safety System technology launched last year with the redesigned Lexus LS model line.

The current production rear pre-crash system - standard on top LS models and optional as part of a safety package on others - uses a millimetre-wave radar device in the rear bumper to detect vehicles approaching from behind.

If the system determines a crash is likely, the system first flashes the car's brake lights to warn the driver of the approaching vehicle and then sensors implanted in the front head rests detect the positions of both front occupants' heads and the 'Pre-Crash Intelligent Headrests' shift instantly to appropriate positions to reduce the risk of whiplash injury if a collision occurs.

The new QAS technology takes this system a step further by additionally adjusting the seat backrests to the optimum position.

So far, QAS is only in prototype form and, installed in a Japanese-market Crown Majesta, was demonstrated to journalists and European government officials at a technology seminar in Germany this week.

Toyota's engineers were tight-lipped about details, but the system apparently uses the same motors that recline the electrically-adjusted seatbacks front (and, if fitted, rear) to instantly reset the seatbacks to the optimum angle.

No launch timeline was given but Toyota first showed the pioneering rear pre-crash system with active headrests (also installed in a Japanese-market Crown Majesta) at a similar seminar in 2005 - and that became available here in the redesigned LS about a year later.

Graeme Roberts