Q. Can specialty vehicle equipment (e.g., radar devices, video cameras, computers, meters, radio trees, shotguns, etc.) still be mounted in cars with passenger side air bags?

A. Yes, but care must be taken to mount the equipment outside of the deployment zone. Air bags inflate with great force and will interact with any object in the deployment zone. Therefore, to reduce the risk of injury to vehicle occupants, GM recommends that the air deployment zone be kept free of any equipment. If a piece of equipment were to become dislodged it could strike an occupant in the vehicle and result in injury. The likelihood of an object becoming dislodged is influenced by many factors, including the proximity of the object to the inflatable restraint, the size and shape of the object, and the means by which the object is secured to the vehicle. In addition to these factors, the trajectory and velocity of a dislodged object can be influenced by the type and severity of vehicle crash.

Objects that are in the deployment zone, but do not become dislodged by an inflating air bag can still affect the performance of the air bag. For example, such objects could tear the fabric or affect the shape of the air bag, thus reducing the ability of the bag to provide restraint.

Q. Is it possible to shield equipment that is installed in the passenger side frontal air bag deployment zone in a manner that will allow full and safe air bag deployment?

A. Due to the complexity of influencing variables, GM is unable to evaluate the potential for shielding expected equipment configurations in all accident scenarios in order to assure that the air bag performance would be unaffected. While shielding may protect certain equipment from being damaged or dislodged, it may also negatively affect the inflation characteristics of the air bag. The air bags' shape, inflation angle, fold pattern, and inflation rate and pressure are developed to maximize the protection capability of the inflatable restraint system. Therefore, GM cannot recommend the placement of any equipment in the deployment zone, even if it is shielded to protect it from damage.

Front air bag systems and instrument panel mounted equipment.

Passenger air bags in GM vehicles deploy in different ways depending upon the type of vehicle and the particular instrument panel design. In some vehicles, the passenger air bag deploys through a discrete door located on the top surface of the instrument panel (top-mount air bag systems). In other vehicles, such as the Chevrolet Tahoe, the passenger air bag deploys through a discrete door mounted on the vertical rearward surface of the instrument panel, above the glove box door (mid-mount air bag system). With these types of top-mount and mid-mount passenger air bag systems, the top pad of the instrument panel remains in place during deployment. Some GM passenger air bag systems, like the system in the Chevrolet Impala, deploy from beneath the instrument panel top pad. These are considered 3/4-mount air bag systems with a "deployable top pad." The entire instrument panel top pad is the "deployment door" from under which the inflating air bag emerges. When an air bag deployment is commanded, the forces from the inflating passenger air bag push up on the instrument panel top pad, releasing special fasteners across the rearward edge of the top pad. This allows the top pad to rotate upward so that the passenger air bag may emerge. The top pad rotates upward to open widest at the right-hand side, and is usually forced upward into contact with the windshield on the right-hand side of the vehicle during a deployment. Instrument panel top-mounted special equipment, such as a radar antenna and control unit or video camera must be positioned to the left of the vehicle center line. This equipment must be mounted as low as possible and securely fastened to the top pad to avoid being dislodged in the event of a crash and possible air bag deployment. In the process of securely fastening special equipment to the top, DO NOT fasten down the top pad itself to any other vehicle component such as the cluster trim plate. As described above, the top pad rotates upward during a deployment. In order to enable the proper deployment of the passenger air bag, specialty equipment installation MUST NOT PREVENT the top pad from rotating upward during deployment. Location and attachment of special equipment should minimize added resistance or interference to upward rotation of the top pad during deployment.

Head Curtain Side Air Bags for crashes to the vehicle sides.

The Air Bag System in your police vehicle may include Head Curtain Side Air bags for front and rear occupants. Most front-to-rear Head Curtain Side Air Bags are designed to deploy downward from the interior roof sides to the bottom of the door windows.

Q. Can Specialty Vehicle Security Barriers be mounted within the side air bag deployment zones?

A. No. The Head Curtain Side Air Bags inflate extremely fast because of the nature of side crashes to the vehicle. Mounting a Security barrier behind the front seats with the ends placed within the side air bag deployment zones will result in unintended interaction between the barrier and the inflating side air bags. To reduce the risk of injury to the vehicle occupants, GM recommends that the side air bag zones be kept free of any customer installed equipment.

Customer-furnished equipment installed to the vehicle roof.

Your police vehicle is designed with an interior roof cover system, which includes internal components for the interior lighting and wiring. The roof system may also include optional side air bag components. Inflation devices may be mounted on the vehicle roof side behind the rear doors as well as air bag tethers retained to the windshield pillars. Care must be taken to avoid damage to these components or interference with their operation when installing roof-mounted equipment such as emergency lighting and communication antennas.

Recommended GM service procedures must be followed to remove and reinstall the instrument panel top pad to ensure that the top pad will release properly in the event of a passenger air bag deployment.

On the right half of the top pad closest to the passenger air bag module, General Motors recommends that no equipment be mounted. When mounting equipment on the driver side of the top pad, GM recommends that the total mass of the top pad mounted special equipment not exceeds eight pounds (3.6 kilograms), since the top pad tends to rotate about the left end. Fasteners used to secure special equipment to the instrument panel top pad, the windshield glass, or to the windshield upper frame (header), should be selected to ensure that these devices will remain attached during a vehicle crash and possible air bag deployment.

Q. Can the installation of push bumpers on the front end of the vehicle affect the deployment of the air bag?

A. It is not likely that installing push bumpers will affect sensing for the air bag system as long as the vehicle structure itself is not modified. GM is not aware of any adverse effects from the many push bumpers that have been installed on current model GM police vehicles with air bags.

Q. How long will the air bag remain inflated?

A. It takes approximately 1/20th of a second to fully inflate the frontal air bags. This is faster than the blink of an eye. The air bags begin to deflate immediately, helping to stop the occupants more gradually.

Q. Can the air bag system be reused?

A. No. The air bags are designed to inflate only once. After inflation, some new parts will be required. These will include the air bag module and possibly other parts (a competent service technician with access to vehicle's service manual and the required tools should replace the required components after a deployment crash).

Q. I’ve heard that the dusts that are released into the passenger compartment from the air bag are harmful. Is this true?

A. For most people, the only effect the dusts will produce is some irritation of the throat and eyes, and that is only if the occupant remains in the vehicle for many minutes after the air bag deployment with no ventilation and windows closed. However, some people with asthma may develop an asthmatic attack from inhaling the dusts. If this happens, they should first treat themselves the same way their doctor has advised them to treat any other asthma attack, and then immediately seek medical treatment.

Q. When should an air bag inflate?

A. The driver’s and right-front passenger’s frontal air bags are designed to inflate in moderate to severe frontal or near-frontal crashes. But they are designed to inflate only if the impact speed is above the system’s designed "threshold level."

In addition, your vehicle has "dual stage" frontal air bags, which tailor the amount of restraint according to crash severity. For moderate frontal impacts, these air bags inflate at a level less than full deployment.

For more severe frontal impacts, full deployment occurs. If the front of your vehicle goes straight into a wall that doesn’t move or deform, the threshold level of the reduced deployment is about 12 to 16 mph (19 to 15 km/h), and the threshold level for a full deployment is about 18 to 24 mph (29 to 28.5 km/h). The threshold level can vary, however, with specific vehicle design, so that it can be somewhat above or below this range.

If your vehicle strikes something that will move or deform such as a parked car, the threshold level will be higher. The driver’s and right-front passenger’s frontal air bags are not designed to inflate in rollover, side impacts, or rear impacts, because inflation would not help the occupant.

The side impact air bags are designed to inflate in moderate to severe side crashes involving the doors. The side impact air bags will inflate if the crash severity is above the system’s designed "threshold level." The threshold level can vary with specific vehicles design. The side impact air bags are not designed to inflate on frontal or near-frontal impacts, rollovers, or rear impacts, because inflation would not help the occupant.

Q. I’ve heard that a deployed air bag produces what appears to be smoke. Is the air bag hot?

A. After the bag has deployed in a crash, the air bag itself will not be hot to touch. Some components within the air bag module will be hot for a short time. A small amount of smoke coming from a deployed air bag module is normal and should not be cause for concern.

Also, when the nitrogen gas is vented out of the air bag, small particles from inside the bag are also vented into the passenger compartment. These airborne particles look like smoke, and some particles are deposited as residue on and around the air bag.

Q. If my vehicle has air bags, why should I have to wear my safety belt?

A. Air bags are in many vehicles today and will be in most of them in the future. But they are supplemental systems only; so they work with safety belts - not instead of them. Every air bag system ever offered for sale has required the use of safety belts. Even if you're in a vehicle that has air bags, you still have to buckle up to get the most protection. That's true not only in frontal collisions but especially in side and other collisions.

*Air bag inflation can cause severe injury or death to anyone too close to the bag when it deploys. Be sure every occupant is properly restrained.

GM offers Antilock Brake Systems as standard or optional on all North American passenger vehicles and light truck lines. The computerized Antilock Braking System (ABS) is designed to keep the vehicle's wheels rotating as the brakes are applied to assist the driver in achieving a controlled stop. Sensors monitor how fast the wheels rotate and feed the data continuously to the ABS computer. The vehicle's brakes slow each wheel as the brake pedal is applied. However, when ABS is activated due to road conditions, the system repeatedly releases and applies pressure to the brakes. The wheels can keep rolling, thus retaining steering ability and enhanced stability while providing a higher braking force on most surfaces than a locked wheel provides.

Q. How exactly does ABS work?

A. In cars without ABS, hitting the brakes can cause the wheels to lock, leaving you unable to steer the vehicle until you decrease the pressure so the wheels can roll again. With an antilock braking system, as you apply the brakes, the ABS computer monitors the wheel speed sensor information. If the computer senses that a wheel is approaching lockup, it sends a signal to the hydraulic modulator to reduce, then to reapply, brake pressure several times a second for as long as you maintain firm pressure on the brake pedal. The process is much like the threshold braking technique used with conventional brakes. However, ABS does it much faster and more accurately than any driver can, leaving you free to focus on steering away from obstacles.

Q. Does ABS reduce stopping distances?

A. Yes, in braking situations where the wheels on a non-ABS equipped vehicle would lock up, ABS will generally provide shorter controlled stopping distance. The amount of improvement in stopping distance depends on many factors, including the road surface, severity of braking, initial vehicle speed, etc. On some surfaces, such as gravel roads, braking distances can be longer, but you will still have the control benefits of ABS. The important capability of ABS is control. ABS provides improved vehicle steerability and stability when braking.

Q. What can affect the ABS advantage?

A. It is important that you follow the maintenance schedule recommended in the owner's manual of the vehicle. Tires should be at their proper inflation level and the brake pads should be checked regularly, etc. While driving, you should sit comfortably, so that your hips are back in the seat and your knees are bent, even while braking. Your foot should be positioned so that your heel is on the floor and your toes are secure on the lower half of the pedal. And, though ABS may reduce stopping distance, remember: The faster you go, the longer it takes you to stop. Keeping a safe distance between you and the vehicle in front of you is always necessary, even with ABS.

Q. What happens if ABS becomes inactive?

A. The ABS electronic control unit has on-board diagnostic capability. If a fault is detected, the vehicle will revert to the base brake system, and the ABS telltale on the dash will be illuminated. Should this happen, the vehicle should be taken to a dealership for repair as soon as possible.

Q. How do I use ABS?

A. Depress and hold the pedal. DO NOT PUMP THE BRAKES (that prevents the system from working). Just hold the brake pedal down and let the ABS work for you. You may feel the brake pedal vibrate, or you may notice some noise, but this is normal as the system works for you.

Q. Should I drive an ABS-equipped vehicle differently than I would drive a vehicle with conventional brakes?

A. Most of the time, under normal driving circumstances, there is no difference, and you should always drive with the same caution and care. It is important to realize that ABS makes a difference only when it is activated-when you have to brake hard-and that would be only when the computer senses that a wheel is approaching lockup. When ABS activates keep steady pressure on the brake pedal and then let the ABS work for you. Don’t pump the brakes or try to find the threshold. Simply hold the brake pedal down and steer if necessary to avoid an obstacle.

Q. Is ABS always active?

A. ABS is always available, but not always activated. ABS is activated only when the brake pedal is applied and the computer detects an impending wheel-lock condition.

Q. Can older cars be retrofitted with ABS?

A. No! The brake system is one of the most important features on any passenger vehicle.

Several products, which tap into the master cylinder and/or brake system performance, are being sold in the aftermarket. Some of these products imply performance similar to new-vehicle antilock brake systems.

However, contrary to their claims, add-on systems that deplete fluid from the master cylinder on brake apply may actually increase a vehicle’s stopping distance. This may cause the vehicle to fail to comply with federal brake standards.

Q. Does ABS always activate at the same speed?

A. No, the system operates when the computer detects wheel lockup, at any speed above eight mph.

Q. Will ABS wear out a vehicle's brakes sooner?

A. A properly maintained brake system will be unaffected by ABS operation under typical driving conditions.

Q. Are there different types of ABS?

A. Yes, there are rear-wheel antilock systems (RWAL) used on some trucks and four-wheel antilock systems available on cars and trucks.

Q. Do federal safety standards mandate ABS?

A. No. Federal standards establish minimum braking performance requirements that all vehicles must meet, but do not specify how they should be met. It should be noted that even a vehicle with failed ABS meets the federal safety standard for stopping distances.

Q. Will a tire size change affect ABS?

A. Use of tires other than original equipment may affect ABS performance. Owners should consult and follow the recommendations contained in the vehicle owner's manual regarding replacement tire size.

Note: ABS will work with original equipment spare tire or tire chains. However, performance is reduced.

Q. Do insurance companies give a discount for ABS?

A. Yes, many insurance companies give discounts that range from 5% to 10%. In the states of New York and Florida, all insurance companies are required to give an ABS discount of 5% on certain coverages such as bodily injury, property damage, collision, and personal injury protection. In other states, the discount varies from insurance company to insurance company. When buying auto insurance, always ask your insurance agent if his/her company gives a discount for vehicles equipped with antilock brakes.

IMPORTANT DRIVING SAFETY TIPS

A. Always maintain a safe following distance. ABS does not allow you to stop on a dime. Generally, a 2-second following distance is considered safe in ideal conditions. Watch the vehicle in front of you pass a fixed marker (such as a sign). Count seconds one-thousand-one, one-thousand-two until your front bumper reaches the marker. If you do not count two seconds, then you are too close to the vehicle in front of you. Also, if the roads are wet or icy, or visibility is poor, you should increase your following distance.

B. Always drive carefully - especially on slippery surfaces. ABS cannot create friction between the tires and the road surface; it can only give the driver the maximum advantage of the existing adhesion. If the vehicle is traveling on a surface with no adhesion, the best ABS in the world cannot provide a shorter stopping distance or good steering.

C. It is a good idea to practice an ABS activated stop and get the feel of the brake pedal. However, please make sure it’s at a safe time with no obstacles in your path. And you only really need to try it once or twice to know what happens.