BY DAVID DALRYMPLE
Although much of the buzz about new vehicles focuses on the motive power sources found on the latest hybrid and all-electric-drive vehicles, still more recent technology has emerged. One mimics a common hybrid vehicle characteristic; others concern new supplemental restraint systems (SRS), especially those in unusual new locations. We will also revisit some construction and material issues, which, although fairly new, are becoming more common.
THE “SILENT” VEHICLE REVISITED
We are familiar with the “silent car” concept when discussing hybrid and all-electric vehicles. When these vehicles are stopped, the drive train’s gasoline engine shuts down, and although the vehicle is still “on” and running, it makes no or very little noise. However, one nonhybrid model, BMW’s 2009 Mini with manual shift, has a “stop and go” feature (photo 1). When you stop the vehicle and depress the clutch, the engine shuts off; it restarts when you depress the clutch again and put the vehicle in gear. For 2010, other nonhybrid vehicles with this feature include the Porsche Panamera, the BMW 5 series, and the Land Rover Freelander, and we can expect many more manufacturers to include this in 2011. Even though this feature will appear on only a small number of vehicles, we can no longer say that hybrids are the “only” silent or “sleeping” vehicles.
|(1) Photos courtesy of author.|
Mini convertible ROPS. The Mini convertibles offer a new rollover protection system (ROPS). Previous Mini convertibles had fixed rollover protection bars behind the rear passenger seat. The new Mini convertible now has a unique pop-up ROPS for that size of vehicle. Most of the pop-up ROPS we have seen are arranged in pairs, normally behind the rear seat. The new Mini convertible has a pop-up rollover bar behind the rear passenger seat that almost spans the width of the vehicle. As a result, the vehicle rear seat sections can fold down so long items can be passed through to the trunk. It eliminates the fixed rollover bar system (photo 2).
Lexus rear seat SRS.The flagship Lexus LS600 and LS600h (hybrid) models have a unique rear seat air bag system. Although the rear seats have seen the advent of side impact and side curtain air bags, this new system is unlike anything we have seen in North America. This system is mounted inside the rear seat’s bottom cushion. On activation, the seat belt pretensioner activates, tensioning the seat belt and drawing the occupant back into the seat. Then an air bag deploys, inflating under the seat cushion and raising it upward to create a “hump” or “speed bump” under the occupant’s thighs. This helps to keep the rear seat occupants in position and prevents them from moving forward. As you can see in photos 3 and 4, the rear seat’s configuration is similar to that of a first-class airline seat. In models so equipped, each rear seating position has an air bag.
Side curtain SRS with multiple inflation modules. Most vehicles now include side curtain air bags, even some fire apparatus. However, when they are installed in vehicles with large side structures, such as station wagons, minivans, and SUVs, the inflation module must generate enough gas to inflate a large side curtain that may be close to 12 feet long. In SUVs equipped with a third row of seating, that row may have its own small side curtains with its own inflation modules. For many of the vehicle types mentioned above, the large side curtain air bag traverses the vehicle’s interior lengthwise and thus requires either multiple inflation modules or a larger inflation module that operates at a higher pressure. So far, manufacturers have favored the first method.
Prior to using tools to cut roof posts or perform side removal evolutions, rescuers must always strip interior trim to find any inflation modules; on these larger-sided vehicles, inspect the roof edge trim as well. The inflation modules may be at either end of the side curtain, at both ends, in the middle above the B post, or inside the curtain itself. Don’t be surprised to find two inflation modules on the same side of the vehicle, as in the Volvo XC90 (photo 5, circles).
2010 Toyota IQ City car rear window curtain SRS. The new Toyota IQ City car (photo 6) was introduced in Europe in January 2009 and is slightly larger than a Smart car but seats four adults. Since it is small and has limited open space, it protects its occupants with nine air bags and enhanced structural reinforcements. However, among these nine SRSs is the world’s first rear window curtain air bag.
As you can see in photo 7, the curtain wraps around the rear seat head rests and protects the rear seat occupants from rear impacts, since there is approximately six inches of space from the rear window to the rear head rests. The curtain’s inflation module is inside the air bag itself and located in the rear roof edge between the rear head rests. As for the rest of the nine systems, count them from the crash recovery system diagram (photo 8). So it’s not just high-end vehicles that have a wide spectrum of SRS systems. Although this vehicle is not yet for sale, look for it in 2010, possibly as the Scion IQ.
2010 Mercedes Benz E Class pelvic SRS.The new Mercedes Benz E Class has 12 SRS systems and is equipped with a second side impact air bag specifically targeting the occupant’s pelvis. The additional pelvis SRS deploys below the seat side impact SRS and the side curtain air bag (photo 9, arrow). This system is designed to further enhance the occupant’s protection during a side impact. Although this is a new system, our existing safety procedures will still protect us.
2010 Ford F-150 K-Bag side impact SRS. Seat-mounted side impact air bags were first introduced in 1995 on Volvos. They have grown from the size of a loaf of bread to much larger and taller today. However, the 2010 F-150 side impact SRS takes on a new shape to further enhance occupant safety. Notice in photo 10 how the side impact air bag is fairly large and shaped like a capital K. This shape will further protect both the upper body and to a certain extent the arms as well as the thorax and pelvis regions. Also note this vehicle’s structural reinforcement and layout, which will affect rescue and extrication operations.
2010 Toyota rear seat air bag.Although this new system is now only available in Japan, it will probably be used very soon in Toyota models here in North America. As you can see from photo 11, it is much like a side curtain but inflates from the rear seat center section. This will protect the rear seat occupants from striking each other and objects and also will provide additional protection to the head and upper torso.
2011 Ford Explorer rear seat seat belt air bag.Another new system for the protection of rear seat passengers is Ford’s integrated SRS in the shoulder belt of the rear seat three-point seat belt. On activation in a frontal or side impact, the air bag deploys passively along the length of the shoulder belt, cushioning the belted occupant. The bag itself unfolds like an accordion, expanding sideways across the occupant’s body. The inflation device is stored within the seat belt assembly in the seat cushion bottom and is an inert “cold” gas, which generally is colder than the outside air. So far this system is available only in the 2011 Ford Explorer but will be used in other Ford models in the near future (photo 12).
Pedestrian protection SRS.This is a new type of safety system we will see more of in the future. Although it is not always an air bag that comes in contact with a pedestrian, these systems will take a variety of pathways. The current system in production in vehicles takes the form of a “lifter” under the hood, a combination of a small air bag and a strut device that elevates the rear of the hood upward, thus preventing the struck person from striking the windshield and rolling over the roof and rearward (photos 13, 14). Another system on the horizon is a bumper SRS to cushion the struck person.
STRUCTURE AND MATERIALS
This is now an everyday problem for the rescue crew. On a very basic level, these materials and reinforcements add tremendous strength in key areas of the vehicle (roof posts, rocker panels, and footwells), and yet the vehicle’s construction allows the vehicle to crumple, crush, and absorb energy from the front and rear, further reducing the already limited interior space for us to work on our patients (photo 15). Consider how this issue alone impacts our operations. We see it firsthand when the tools we rely on don’t work well, if at all. The power hydraulic tool advertisements often focus on cutting forces of their “uber” cutters and reference “five-star crash-rated” vehicles and new technology materials. Consider the operational service life of a power hydraulic cutter today—when will it be obsolete and unable to cut the new technology materials? That time is rapidly approaching. If it’s not already here, it will be in five years.
Although a great tool, even the reciprocating saw has its limits. It isn’t the saw itself but the blades. Many rescuers use rescue or demolition blades, but even they may be ineffective on the ultra high-strength materials used in today’s vehicles. In photo 16, this B post is reinforced with a boron tube.
Consider our patients. Are there more extrications or fewer? Are those patients physically stuck or medically entrapped? Think about the sheer lack of space available inside any vehicle today to manage a patient. What about the injury patterns of today? I know prehospital trauma life support (PHTLS) makes much of kinematics of trauma in a motor vehicle accident, but how many head and upper body injuries do you see today? How about lower extremities and pelvic injuries? Which is really more prevalent in today’s vehicle crashes? Vehicle structure and materials affect not only disentanglement and tool selection but also injuries and kinematics.
Let’s look at a “common” 2010 vehicle that illustrates these concerns: the Ford F-150 pickup truck. Look at photo 10, and note that in addition to the reinforcements in the “usual” areas (e.g., the base of the B post), there’s a boron steel tube that runs from the A post upward toward the roof line and along the roof edge to the C post, where it meets another ultra high-strength steel tube that then runs down the C post to the rocker panel. The rocker panel material is advanced high-strength steel that actually gets stronger when it is crushed.
Now take a look at the photo of the Volvo XC60 D post cut (photo 17). The post is wide, and all of the vehicle’s glass is laminated for added overall structural integrity. But look at the cut itself: Not only is the post filled with foam (another reinforcement), but because of the post material and its reinforcement (advanced high-strength steel, probably boron steel), it took multiple cuts from a variety of angles to sever this post, roughly three to four minutes to sever one roof post. Remember also that these advanced materials are not just steels, carbon fiber composites, and other alloys; even advanced window glazing will play a greater role in the future.
As rescuers, although we still need to keep on top of the motive power changes now and in the near future, we also need to keep a sharp eye on new vehicle construction materials and how they affect our tools and tactics. We will see more air bags and batteries in more unusual locations, but vehicle construction and materials will present the most difficult challenges we will continually need to overcome as time and technology go forward. Power hydraulic tool makers are observing how their tools perform when they interact with new vehicle materials. But we rescuers are the first ones to encounter these issues, so we need to stay focused on vehicle technology concerns and be creative and flexible in resolving these issues.
DAVID DALRYMPLEis a career EMS provider for the RWJUH Emergency Medical Services in New Brunswick, New Jersey. Previously, he was the rescue services captain for Clinton (NJ) EMS/Rescue. A member of the International Society of Fire Service Instructors (ISFSI), he has been involved with emergency services for 26 years. He is the education chair of the Transportation Emergency Rescue Committee-US (TERC); a certified international level extrication assessor; the executive educator for Roadway Rescue LLC; road traffic accident advisor to the Expert Technical Advisory Board of the IETRI; and a member of the IAFC Specialized Technical Rescue Committee. He received the 2007 Harvey Grant Award for Excellence in rescue. He is a NJ-certified fire service instructor and a certified ICET (Netherlands) registered International SAVER instructor. He writes the “Extrication Tactics” column for Fire Engineering.