Related: Automotive Production
You are in your Saab cruising along at 55 mph when you approach a 35-mph zone, you slow down but not quickly enough so that you pass the sign at 42 mph. Suddenly, the throttle pedal pushes back hard at you causing you to decelerate to the speed limit. Shortly after, you pass a 55 mph sign, so you push the throttle hard down to accelerate past a bus, only to receive another severe jolt in the right leg as you hit 55 mph. The trouble is, you are in the left lane, the bus by now is going the same speed, and you have someone on your tail—and you want to turn right at the next intersection. While there is a clear road in front of you and the bus, there is nothing you can do about it. Welcome to the new world of motoring, the world where external forces take away some of the important controls from the driver. It is happening now, in Sweden, on an experimental basis. So far...
Trollhattan, Sweden, is virtually a one-horse town. It has a population of 53,000, 7,000 of whom work for Saab. Last year, its road death toll was two. It is here, though, that it was thought appropriate to carry out an experiment to see whether external forces on the car (e.g., clearer roads signs and various traffic calming measures) led to an even further reduction in road injuries and to generally safer drivers. The designated 39 km of road, six in the town itself and 33 forming a loop to the east, run in co-operation between various local and state transport and road authorities plus Saab Automobile, is part of the Swedish government's "Vision Zero" concept. This is a project aimed at reducing human injury on the roads to nil through a variety of cost-effective measures.
As the headquarter town of Saab, the Swedish automaker is naturally at the heart of this experiment, providing some cars that have been rigged out with all kinds of apparatus including external control and a detection kit that makes the driver take a breath test before it will start if it detects any alcohol on his or her breath–an admirable but Orwellian touch.
This introduction to a future that looks to some bleaker by the minute was but a preamble to a safety seminar held at Saab's auto museum in Trollhattan which concentrated on a real-life accident scenario and the lessons to be learned.
Like many automakers, Saab has an accident investigation unit that investigates up to one or two accidents a day while a thorough investigation is normally carried out once a week by its engineers at a dealer workshop. One such accident, where a three year old 9-5 that failed to stop at a major road had been T-boned more or less side on by a Toyota Hiace van, was the subject of Saab's safety seminar.
Looking at the car, it seemed improbable that anyone could survive, but the Saab's driver did, as did the Toyota's, who was fortunately wearing his safety belt. Unbelievably (for we are talking Sweden), the Saab driver was unbelted, but as she was hit from the side, it was stated that it would not have made any difference in this situation, anyway. While she did suffer torn insides, there were no fractures. In fact, the only casualty was her dog in the rear seat that had to be put down with a broken back.
Saab's safety engineers learned a great deal about their wreck of a car. As there is less scope for deformation to absorb crash energy in side impacts, the side body structure has been designed to distribute impact forces as widely as possible via reinforcements in the sills and the B-pillar. In addition, the latter is designed to behave as a pendulum during heavy side collisions. The centre section is made from high-strength steel and is very rigid so that it will not deform and intrude into the interior. In effect, the entire pillar "hinges" inwards, like a pendulum, from the point where it joins the roof structure. In this way there is unlikely to be sudden intrusion, and the most robust part of the human body, the pelvic area, will be subjected to most of the crash energy. This reduces the risk of injury to more sensitive parts of the body, such as the rib cage, head and chest.
However, one of the things that worried Saab's safety experts on this particular car was the fact that the base of the A-pillar had started to tear, something that had not shown up before in testing, while the rear door lock was also torn due to the severity of the impact. One item that did perform as designed, though, was the cross-member in the seat back that deformed in the way that Saab predicted by moving forward rather than backward. One factor, though, was while the Toyota hit the Saab from the side, it was slightly angled to the front. All these factors will be taken into account in the design of the next-generation Saab.
While all the airbags did their job, Saab is also investigating how the car's occupants can be kept more in place rather than thrown around, and maybe out of their seatbelts, thereby sustaining further injuries. Its answer, although only in the experimental stage, is the Saab Supplementary Belt (SSB). This concept features an additional two-point shoulder belt mounted in the top of each front seatback, at its inboard side, which is pulled down across the occupant's chest. It can be used as an optional addition to the conventional three-point harness. It also acts as a pre-pre-tensioner, taking up any slack if it detects panic braking, as it is activated through an accelerometer in the brake pedal.
SSB has been devised to be most effective in side impact scenarios on the opposite side of the car from the driver or front passenger, frontal impacts with a small 10-15% overlap, oblique "side swipe" impacts along the side of the car, or fast continual roll-over actions. It has to be said, though, that in the test rig that Saab used at the seminar to show its efficiency, activated when a special button caused the high-speed electric motors to take out the slack, that not one single woman liked the experience, catching different parts of their body in a rather gripping and uncomfortable way.
What was more usefully gained out of the seminar were some interesting figures produced by Prof. Dr. David Viano, the person accredited with devising the active head restraint. First seen on a Saab, and therefore branded the "Saab Active Head Restraint," it was actually a Delphi invention–or so we have always been led to believe. It turns out, though, that the inventor as such, has always worked for General Motors and not Delphi, even when it was part of GM.
Introduced on the Saab 9-5 as a world-first in 1997, the active head restraint has been the subject of a great deal of research to see whether it really does make any difference. One major study has been conducted in Sweden by Dial, one of the country's leading insurance companies, to compare its performance against earlier Saab models fitted with conventional head restraints. It was also used to assess the validity of laboratory test results using dummies. All the accident studies took place on Swedish roads over an 18-month period from September 1998 to April last year, and involved single rear-end impacts only. In almost 80% of the cases, the cars were stationary.
Injuries were categorized as short-term pain, lasting up to one week, medium term injury, up to 10 weeks, and long-term injury, persisting for more than 10 weeks. A total of 85 cases involved Saab 900/9000s with standard headrests and 92 cases in Saab 9-3 and 9-5s with active head restraints.
The report showed that the proportion reporting no injury at all rose from 47% (40 cases) in the 900/9000 group to 59% (54 cases) in the 9-3/9-5 group, a significant 25% improvement. Whilst the proportion reporting short-term pain was more or less similar in both groups, 35% compared to 37%, there was a remarkable 75% improvement in medium- and long-term injuries. Just four people in the 9-3/9-5 group complained of medium- to long-term pain compared to 15 in the other. An analysis of the long-term injury cases showed in the 9-3/9-5 group that all three individuals had a pre-existing whiplash condition that was not aggravated at all. In the 900/9000 group, five out of the seven long-term sufferers complained that their pre-existing condition had worsened. Interestingly, no women using the active head restraint suffered from whiplash injury and none of the seats had to be repaired or replaced.
"These finding demonstrate conclusively the effectiveness of the Active Head Restraint system," said Stefan Olsen, Saab safety development engineer. "Our tests with dummies during its development worked well, but this study shows that in real-life situations it functions even better than we had expected."
Saab thus keeps the momentum going as a standard bearer of safer cars. Whether it might be overstepping the boundary with its remotely controlled throttle pedal and alcohol-detection device is for others to decide, but it nevertheless ensures that it remains at the cutting edge of vehicle safety technology.