While most of the recent safety advancements in modern automobiles have successfully filtered into modern patrol vehicles, one item that has caused nearly as many headaches (no pun intended) as it has success stories is the airbag system. This is because law enforcement professionals are one of the few driving pools who surround themselves with items inside their vehicles that directly conflict with airbag operations in crash situations.
This problem has been magnified in recent years with the addition of numerous auxiliary airbags designed to enhance occupant safety on the sides, the top, the lower dash area, in the rear seat area and so on. In some vehicles currently for sale on dealer lots, there are more than 20 airbags installed in a single vehicle. While most current law enforcement fleet vehicles are limited to front, side and sometimes side-curtain airbags, this still represents multiple explosions that must be managed in concert with duty equipment such as prisoner cages, MCTs, spotlights, radar units, cameras, etc. In other words, all the toys we like having in our cars could become projectiles and kill us in a crash if airbag deployment issues aren t considered.
Before I address efforts to reduce or eliminate these potential threats, let's first look at the history and operation of airbags.
Do They Work?
I once responded to a call of a driver who had intentionally attempted to kill himself by slitting his wrists and driving his vehicle into the side of a bridge abutment at high speed. He might have succeeded except for two things. First, he miscalculated the angle he needed to hit the bridge at. Second, he was driving a 500 Series Mercedes Benz, arguably one of the safest cars in the world. So, when he hit the edge of the bridge footing, the safety cage, soft interior materials and multiple airbags performed as designed, and the worst he ended up with in the deal was some sore wrists.
We can all deduce the lessons learned on that one, but there s no escaping the fact that airbags remain a unique product in today s marketplace. Nearly every consumer passenger vehicle comes standard with airbags for at least the driver and front passenger. This means that drivers of vehicles manufactured for sale in the last 15 years have a large, explosive-laden pillow in front of them at all times, and that they really have no idea how it works, when it works and what it can do until the big event occurs.
This grows more complicated when you consider that when it comes to airbags, manufacturers have faithfully subscribed to a if two is good, 14 is better philosophy. There are some valid reasons for this. According to the NHTSA, since 1990 there have been more than 3.3 million airbag deployments with more than 6,300 lives saved. For those of us who work traffic crashes as part of our daily duties, we've seen many times where airbag deployment has benefited the occupants in reducing crash injuries. We ve also seen times where it hasn't benefited the occupants due to improper seating arrangements, the type of crash and, more commonly, the lack of seatbelt use in conjunction with airbags. More on that later, but NHTSA has already recorded more than 175 fatalities because of airbag deployment, and those vehicles didn t have MCTs, cages or radar units installed in them at the time of the crash.
So, do airbags work? Yes. Do they come with some significant safety considerations as well? Absolutely.
Remember when you were a kid, and you practiced your high-dive antics off the edge of your bed? It didn t take too many thumps on the bare floor before you figured out that placing a few sofa cushions on the floor, much to Mom's dismay, functioned ideally as an energy-absorption zone. In the same way, the idea of adding a cushioning pillow for occupants of moving vehicles stretches back to WWII when engineers were trying to find ways for military pilots to survive hard landings.
Fast forward to 1971 when Ford built its first group of airbag-equipped vehicles. General Motors followed in 1973 with a Chevrolet model that, interestingly, was only sold for government use. For consumers, the first real model available with an airbag was the 1973 Oldsmobile Toronado. Interestingly, the only airbag in that vehicle was on the front passenger side. Not surprisingly, these early airbags were crude in design and deployment, which compromised their effectiveness. Still, the door had been opened on airbags, and manufacturers began to slowly incorporate them into their models.
Chrysler set the standard in 1988 when it offered airbags as standard equipment on all of its models. Then, in 1998, the NHTSA made airbags a standard requirement. This means it's almost certain your patrol vehicle has at least two airbags that you need to take into consideration when on patrol.
A Rocket in Your Steering Wheel
When it comes to crashes, the world is reduced to milliseconds. The typical crash event typically begins and ends within 200 milliseconds. Because of the crash forces involved, engineers have the first 50 milliseconds or so to address how to best minimize the transfer of energy from the impact to the occupants. For front airbags, this means the system must sense the crash, decide to inflate the bags or not, and inflate the bags within approximately 25 milliseconds. For side impacts, this time frame is reduced to approximately 5 milliseconds, according to the NHTSA.
This means the airbag must inflate in the blink of an eye, requiring an extremely powerful propulsion system. Three components inflate the system, including the sensor(s), which is installed in various parts of the vehicle. The sensor either measures deformation of a particular part of a vehicle, or the crash acceleration forces through an accelerometer built into the sensor chip. When a crash occurs, a deformation switch is tripped by the compression of sheet metal, bumper, etc., thereby activating the system. With an accelerometer, the sensors trip the system when acceleration forces reach a predetermined level based on sophisticated algorithms. In early systems, the mechanical sensor directly connected to the airbag deployment, but newer systems employ computer interfaces that evaluate the severity of the crash, the occupant s position, whether or not seatbelts are in use and the occupant s weight before deciding on the level of airbag deployment. If deployment is required, the sensor tells the second component of the system, the inflator, to activate.
The inflator is filled with a solid propellant comprised of sodium azide, which converts to nitrogen when ignited. This immediate conversion to nitrogen causes a tremendous explosion, thus both inflating and propelling the third component, the airbag itself, into your noggin at approximately 200 mph. The airbag itself is made of nylon and is packed with a coating of cornstarch or talcum powder to keep the bag from sticking to itself when packed inside your dash, steering wheel, etc. The term bag is a bit of a misnomer because its surface is covered with tiny holes that allow the nitrogen gas to escape almost immediately after inflation. In fact, the airbag is actually deflating by the time you strike it, which keeps it from being rock-hard and potentially causing more injury.
All of this takes place in less that 50 milliseconds, even less with a side or curtain airbag. It can turn the inside of a patrol car into a very dangerous place for a number of reasons.
Issues & Solutions
We carry a lot in our cars each and every day: notebooks, ticket books, code books, posse boxes, coolers, cameras, flashlights, etc. We also sometimes carry another human in some jurisdictions your partner. Space is already limited in most production vehicles, so adding the above plus an MCT, a radar unit, an in-car camera setup, headliner-mounted emergency lights, LoJack, map lights, spotlights, etc., can really limit the space an airbag needs when it deploys.
When accommodating airbags in a patrol car, there are two areas to look at: operator influence and vehicle design. The first is easier for us to do because we can control the outcome simply by adjusting or altering the way we carry our gear. When I first started in law enforcement, my day would begin with me chucking my leather citation book onto the top of the dash hard enough to wedge it up against the windshield. It made a perfect shelf to retrieve my book when needed. Trying that today might get me a leather-bound headache, so now I carry my cite book in an upright seat organizer.
The same goes for handcuffs. How many times have you used the spotlight arms in the A posts as a convenient handcuff holder? You can imagine what a 200-mph airbag hit on that passenger-side spotlight arm would do to those cuffs. Yep, they d be off faster than a tie-dye shirt at a Young Republican convention. So, find another spot for them in the doors or in your duty bag, or switch to a dual-cuff case if you don t already have one.
Another area: sun visors. There are numerous visor organizers available that store pens, business cards, etc. I use two in my own patrol car. The key: Don t overload them with items to the point that they sag and cause a potential problem. And resist placing your cell phone in an outer pocket. In a crash, low is good, high is bad. Besides, since Motorola isn t sponsoring your cell phone bill, do you really want an imprint of their logo on your forehead?
Your seating and hand positions are also critical. In analyzing airbag injuries, automotive safety engineers have determined airbag injuries can prove most severe if the person is struck within the first 2 3 inches of bag deployment. They have settled in at 10 inches as the threshold of safety for distance. Some of us are a little more vertically challenged than others and might need to sit closer than that. But there are still some things you can do. Start by moving the seat far enough back that your arms have a natural V pattern when grasping the wheel. Newer patrol vehicles such as the Chevrolet Tahoe PPV have adjustable foot pedals that can allow you to sit further back and still reach the pedals.
Another option: Angle the steering wheel toward your chest instead of your face. A deployment in this area will spread the force over a greater area, and your vest should help cushion the blow. (You do wear your vest, right?) Another critical habit harkens back to EVOC days with hand position on the steering wheel. If you hold the wheel at the nine and three position, it will keep your hands, arms, etc., out of the direct path of the airbag. If you have one hand draped over the wheel at the high-noon position and the airbag deploys, you will have a good time explaining how you got into a boxing match with yourself, and lost. So, keep the hands to the sides of the wheel. Of course, it almost goes without saying that you should wear your seatbelt when driving because that s the cornerstone of occupant safety.
Finally, if you don t use something on a regular basis while on patrol, put it in the trunk. The less flying around in a crash, the less chance of injury.
Many of us don t have much control over this area, so there s little we can do except become really good friends with the installers to see about moving things around for safety. If you re the one ordering equipment for your department, consider the following options. The first is an airbag defeat switch, which allows the operator to selectively switch the arming of the passenger-side airbag. This is critical if you plan on using a laptop configuration that, while possibly airbag-compliant when stowed, is definitely not compliant when employed. Another reason might be the occasional transport of another officer in the passenger seat. While most new patrol vehicles have weight sensors in the front passenger seat, Ford Airbag Engineering states the passenger-side airbag on 2003 2004 Crown Victorias can deploy with as little as 7 lbs. of pressure on the seat. This means if you place a bag on the seat weighing at or above that amount, the passenger-side bag could deploy in a crash, causing issues.
Interestingly, Chrysler has eliminated the occupant-seat sensor in all of their models for 2007, including the Charger, Magnum and Durango. This means the passenger-side bag will always deploy in a frontal collision.
The installation of an airbag control switch such as the one AOI Electrical offers can make good sense in protecting officers and equipment. For side-curtain airbags, AOI will soon offer a control switch for those bags as well because they can directly impact the cage, causing problems.
Cage manufacturers have also altered their designs to accommodate side and curtain airbags. Setina offers a collapsible shield on each side of the cages it makes for vehicles with side airbags. The deformable plastic sides allow for protection against fluids, odors, etc., but also collapse and break away if impacted by a side airbag. As for other equipment, consider camera systems that are incorporated into the rearview mirror area, and closely monitor the installation locations of radar units. For MDTs, choose centrally located mounts to ensure the unit remains between the two airbags should they deploy.
Finally, when ordering vehicles, inquire about adjustable pedal setups they can make a big difference in safely distancing your officers from the airbag.
Now that you understand what airbags are, how they work and the issues they present, there's a lot you can do to maximize their positive attributes while minimizing their dangers in the patrol vehicle environment.
Vendor Contact Info
Setina Manufacturing Company
2926 Yelm Hwy SE
Olympia, WA 98501