- Compatibility brackets protect lower-riding vehicles in crashes
- Safety belt pretensions that activate in rear impact are industry first
- Roof-mounted head curtain side air bags add rollover protection
GM’s new 2007 full-size SUVs are designed to be among the industry’s safest and most secure vehicles. The vehicles provide a 360-degree perimeter of safety protection and provide increased compatibility with other vehicles.
New features include available roof-mounted head curtain side air bags, which are integrated into strengthened chassis and body structures to provide excellent passenger protection. Stabilitrak electronic stability control with rollover mitigation technology is standard.
“These vehicles envelop occupants with a comprehensive safety system that is built from a foundation of segment leadership in safety technology” said Gary White, General Motors North America vice president and vehicle line executive for full-size trucks.
GM’s full-size SUVs have a heritage of safety innovation. Previous-generation vehicles were the first vehicles in the industry to offer a passenger sensing system to suppress deployment of the front passenger air bag if a child or person of smaller stature is detected. GM’s full-size SUVs also were first to offer dual-stage air bags, standard four-wheel antilock brakes and a standard electronic stability control system.
In the new models, comprehensive safety encompasses crash avoidance, occupant protection and post-crash care. The safety portfolio features three linked avenues of protection: vehicle structure and dynamics; occupant safety features, and driver control features.
It starts with a stronger frame and body structure. Crash avoidance, for example, is bolstered through enhanced driver control dynamics, such as wider front and rear tracks, as well as more responsive suspensions – including a new coil-over-strut front suspension design and new rack-and-pinion steering. StabiliTrak electronic stability control with roll-over mitigation is standard on all models.
Here are the safety highlights of GM’s 2007 full-size SUVs:
- Vehicle structural and safety dynamics :
- Body-on-Frame (BOF) structure with comprehensive use of high-strength steel
- Stronger, stiffer frame, including all-new front bay design for improved crush dynamics and provisions for improved vehicle-to-vehicle compatibility
- Wider front and rear tracks enhance stability, handling and lower the center of gravity
- Enhanced body structure for superior occupant protection
1. Occupant safety and security :
- Standard dual-stage driver’s front air bag and dual-stage outboard-front passenger air bag with passenger occupant detection system
- Available roof-mounted head curtain side air bags with tethers and roll-over protection for all seating rows
- Front safety belt pretensioners
- A 360-degree sensing system for fast, accurate impact analysis and airbag deployment/seatbelt pretensioner activation
- Enhanced head-impact protection
- High-retention front seatbacks help restrain front seat passengers during a collision
- Three-point safety belts in all seating positions (except base vehicle front bench center seat position)
2. Driver control :
- Enhanced driving dynamics, including standard StabiliTrak electronic stability control with rollover mitigation
- Autotrac active transfer case
- Larger-capacity four-wheel disc brake system
- Standard door child security locks
- Standard four-channel ABS and traction control
- Standard tire pressure monitoring system
- Standard Passkey III anti-theft system
- OnStar system Gen 6
- Available locking rear differential
- Available Ultrasonic Rear Parking Assist
- Available rear-view camera system
- Available remote start capability
- Available rain-sensing wiper system
Vehicle structural and safety dynamics
The vehicles are built on a stronger and stiffer, fully boxed frame that is designed for improved crash-energy management. The front frame section, for example, has improved crush dynamics that provide the equivalent of 17.7 inches (450 mm) of additional crush space in vehicles that are only approximately 3 inches (76.2 mm) longer than their predecessors. The frame also is designed for improved vehicle-to-vehicle compatibility.
The all-new, fully boxed frame features hydroformed front and rear sections, as well as strategic placement of high-strength materials. The frame also features more reinforcing cross members than the previous-generation models, as well as stronger mounting brackets in key areas. The hydroformed front section frame rails have a wall-thickness of approximately 3.2 mm and are straighter with a more consistent cross-section than the previous-generation frame – a design that delivers improved axial crush performance. Also, the new frame is 49 percent stiffer than the predecessor, which helps resist bending or twisting during a crash. (See Chassis Systems section for more information.)
The front rails of the frame are designed with enhanced vehicle-to-vehicle compatibility with smaller or lower vehicles during a crash. Compatibility brackets located on the forward position of the lower front frame rails are designed to buckle in a frontal or offset collision, reducing the motion of the frame into the smaller vehicle. The location of the brackets meets all car structure heights. GM crash-tested the tallest of the SUV models with some of the shortest cars on the road for crash compatibility.
Along with the frame, the upper body structure is designed to manage the energy of a crash, including improved side-impact and rollover performance. Strategic placement of high-strength steel throughout the frame and body structure provides additional support and helps maintain passenger compartment integrity during a crash.
The ’07 SUVs’ body structure enhancements also include:
- A new A-pillar reinforcement made of high-strength steel that resists buckling
- High-strength steel roof-rail reinforcements on both sides of the B-pillar where they meet the roof rails contribute to improved roll-over performance
- A diagonal brace made of high-strength steel located beneath the driver and front passenger “toe” pan provides reinforcing strength for the vehicle and lower torso protection for passengers
- An all-new, single-piece rear “D” ring offers increased dimensional accuracy and reinforcing structure
- An enhanced front door hinge box adds strength to the forward section of the front door D-ring which helps reduce deformation during a crash
- Stronger knee bolster brackets (welded to the instrument panel cross beam) are designed to withstand higher loads during frontal impacts
- A new “Z” bracket adds strength to the area where the front-of-dash section of the body structure meets the floor pan, as does structural adhesive applied to the same area
The strength of the frame and body structure, extensive math modeling and internal crash tests contribute to GM’s expectation that the new SUVs will be among the segment’s top performers in frontal barrier and frontal offset crash tests.
Other features that contribute to the SUVs’ strong performance during a crash include:
- Impact beams – Front and rear impact beams are designed to absorb low-speed crashes and minimize vehicle damage. A more severe crash will cause the energy-absorbing bumper beam to crush. There also are two side-impact beams in each door.
- Passenger head protection – Energy-absorbing foam padding and trim on the A-, B- and C-pillars, as well as the roof rail, are designed to spread the energy of a crash by crumpling and crushing on impact. The headliner also contains energy-absorbing material.
- Seat safeguards – High-strength front seatbacks provide restraint during a rear-end crash. There also is a crushable pan between the seat frame and seat cushion – the pan will crush to absorb energy in the case of a high load.
Occupant safety and security
Air bags: Dual-stage driver and outboard front passenger air bags are standard on all models. Children and smaller-stature front passengers are protected with GM’s passenger occupant detection system. Roof-mounted head curtain side air bags are available on all models. These air bags inflate to restrain outboard passengers in all seating rows and are equipped with special tethers that hold the bags in place for several seconds for increased rollover protection and passenger containment.
The air bag system’s sensors determine the severity of a crash, indicating whether the primary stage of inflation or the primary and secondary stages are required for maximum protection. The sensors are located at the front of the vehicle, on the radiator support beam.
In the event of a side-impact collision, the head curtain side air bags act like a protective curtain, unfolding from the roof rail between the A- and D-pillars in three-seating row vehicles and A- to C-pillars in two-row configurations. The first- and second-row positions are restrained by a larger side air bag and the third row has a dedicated air bag. Each side air bag has its own dedicated inflator for optimized fill rates into each curtain.
The roof-mounted head curtain side air bag system incorporates one of the segment’s first rollover indication sensors, which is located in the vehicle’s center tunnel. The sensor monitors the vehicle’s angle variance from level. If the angle indicates an impending rollover, the side air bags will deploy to provide an extra measure of occupant protection and containment. In this instance, the side air bags stay inflated longer than during a side-impact collision, because rollover incidents may last longer and the inflated air bags help keep occupants inside the vehicle.
Occupant protection from secondary impacts also is a feature of the roof-mounted head curtain side air bags. Based the severity of the event, the bags’ “curtains” are deployed whenever the second stage inflation of the frontal air bags is triggered. GM’s safety engineers reasoned that a collision severe enough to trigger both stages of frontal air bag inflation is likely to cause a secondary collision. In this instance, the air bags deploy and remain inflated for several seconds following the initial collision, ready for a possible second impact.
Front safety belt pretensioners and rear safety belt features: Front safety belt pretensioners are standard on all models. In the event of a crash, they take up slack in the safety belt webbing to help secure the passenger in the seat and prevent him or her from “submarining” during the crash. It also helps to hold the passenger in position, so deceleration is at the same, slower rate of the vehicle and not a more abrupt stop.
The pretensioners are activated by a sensor, which triggers a pyrotechnic device that almost instantly reduces slack in the belt webbing. The safety belts are equipped with low-friction D-rings and low-effort retractors, so there is minimum pressure on the occupant, making the belts more comfortable to wear. Also, the pretensioners will activate in a rear-end crash – an industry first in GM’s full-size SUVs.
Second- and third-row seats have three-point safety belts in all positions. An added feature is an available comfort guide on the outboard seatbelts. This device has an elastic cord that helps to properly position the shoulder belt on smaller-stature occupants. The second- and third-row seats also come equipped with LATCH system child seat anchors, for both top tethers and lower latches, to simplify installation of child seats with these features. These anchors, which are secured to the body structure, are provided in the rear outboard seating positions.
Sophisticated sensors: The new SUVs are equipped with the segment’s most comprehensive system of crash impact sensors, which work together to provide 360 degrees of sensing tied to the central Sensing Diagnostic Module (SDM). This provides faster, more immediate data that is used to activate the vehicles’ numerous air bag safety features. The sensors include:
- Two forward sensors located on the frame’s most forward cross member measure deceleration crush, enabling SDM decisions in less than 10 milliseconds
- Four side-impact sensors – one on each side-door beam – provide more rearward sensing of side impacts than previous models
- A roll-over sensor that continually measures the vehicle’s pitch angle and signals the SDM if the angle indicates in imminent roll-over
- Rear sensors that detect rear-end impacts and trigger the safety belt pretensioners
Driver control
While designed to help protect passengers in the event of a crash, the new 2007 full-size SUVs also have features designed to avoid or lessen the chance of a crash. This starts with a wider front and rear track, which helps provide a more secure driving feel and a lower center of gravity. Also, the improved responsiveness while driving – delivered by the new coil-over-shock front suspension, enhanced five-link rear suspension and new rack-and-pinion steering system – provides the driver with a heightened feeling of control.
StabiliTrak electronic stability control: GM’s sophisticated StabiliTrak electronic stability control system is standard on all 2007 full-size SUV models. Partnered with the new brake system and four-channel, four-sensor electronic brake controls, the system provides more precise, controlled ABS stops, as well as enhanced traction/yaw stability.
The Stabilitrak system has new rollover mitigation technology. Rollover mitigation adds software algorithms that use Stabilitrak sensors to proactively predict vehicle “tip up” on a flat road surface, and applies brake force to the outside front and rear wheels in order to reduce lateral force in the vehicle. This brake force intervention can help reduce the likelihood of a rollover in certain circumstances – including “fish hook” maneuvers that involve sudden and rapid back-and-forth steering.
On 4WD models, StabiliTrak uses brake control to precisely manage the speed of each wheel as well as torque across the front and rear axles. On 2WD models, the system precisely controls the speed at each wheel and manages side-to-side torque on the rear differential. Individual brake sensors at each wheel provide signal the control module, enabling it to aggressively adjust brake pressure. However, traction is controlled by transferring torque across the rear axle – rather than front and rear axles, as in 4WD models). When the vehicle is on a slippery surface, the traction system increases torque to the rear wheel that has the most traction.
On 2WD and 4WD models, the vehicle brake system provides torque-biasing to enhance traction and engine management as required to assist in controlling traction and yaw stability. The Autotrac transfer case’s control algorithm has been integrated with the StabiliTrak and ABS systems to provide enhanced vehicle stability by managing the front-to-rear torque distribution.
StabiliTrak is always on and fully functional. It is automatically enabled, providing full stability, traction and ABS control, whenever the vehicle operates in forward gears. The system intervenes when it senses one or more of the wheels slipping or when the vehicle is not following the driver’s intended path. It detects slippage during braking or acceleration and automatically adjusts individual wheel brake pressure, engine torque and, on 4WD Autotrac models, adjusts front to rear drive torque distribution, as required, to achieve optimal control.
Autotrac: Four-wheel drive models feature the Autotrac active transfer case, which helps keep the vehicle sure-footed in slippery driving conditions. When shifted to the “Auto” mode, Autotrac engages all-wheel drive traction automatically. The vehicle operates in rear-drive mode, but torque is automatically split between the front and rear wheels when the system senses all-wheel drive traction is needed. The process is smooth, quiet and almost undetectable.
New, segment-leading pre-emptive controls allow the Autotrac system increase the torque to the front axle on slippery roads prior before slippage occurs. This can increase control because the system anticipates rather than reacts to slippery conditions. Autotrac also is integrated with StabiliTrak, which now incorporates the signal from one of Autotrac’s slip-detection sensors to provide another measure of input to the stability control system. This new input allows StabiliTrak to operate more efficiently.
An available locking rear axle also helps provide sure-footed traction, particularly when towing. When rear wheel slip is detected, the rear axles lock to turn at the same rate, providing all available torque to both wheels. This is helpful for special circumstances, such as pulling a boat and trailer up a launch ramp.
New four-wheel disc brake system: A larger-capacity, four-wheel disc brake system with a new, four-channel ABS is designed to provide the new SUVs with superior stopping capability and the segment’s best braking feel. ABS is standard on all models, along with a full-function traction control system (traction control only on 2WD models). The headlining elements of the new brake system include larger-diameter front and rear disc rotors and new, stiffer brake calipers.
The front rotors measure 13 inches in diameter (330.2 mm), an increase of 1 inch (25.4 mm), or 15 percent larger. The front rotors also are thicker, with large cooling vents, providing enhanced performance and durability. The cast iron, dual-piston front brake calipers are 50 percent stiffer than before, which reduces the tendency for flexing during hard or prolonged braking. The stiffer calipers, along with dual pistons, contribute to a more direct and stronger brake pedal feel.
Rear brakes feature standard vented discs that measure 13.5 inches (342.9 mm), an increase of 0.5 inch (12.7 mm) – approximately 7.5 percent larger. A revised single-piston rear brake caliper design contributes to reduced brake noise and more immediate braking response. Both the front and rear brakes use new, non-asbestos brake pad linings that can deliver up to 40,000 miles of performance during normal use.
The new brakes are complemented by a more robust, twin piston brake application system, including a larger master cylinder and active brake booster. Engineers tuned the application system to optimize the pedal feel and brake system responsiveness. It requires less pedal pressure to provide a more immediate brake response, delivering a dramatically improved feel.
A next-generation Bosch 8.0 ABS system is standard on all 2007 full-size SUVs. It has more precise valve control the requires less cycling of fluid from the brake master cylinder, resulting in reduced noise and enhanced braking feel when ABS is activated during braking. The new ABS system also is less complex and has reduced mass when compared with the previous system.
Full-function traction control uses the ABS system to regulate brake pressure to help provide enhanced traction for 2WD vehicles.
Ultrasonic Rear Parking Assist: The new optional Ultrasonic Rear Parking Assist system provides visual and audible warnings of objects behind the vehicle. The system operates when the vehicle is in Reverse, using fours sensors located at the rear of the vehicle. The new system is available in conjunction with a new, optional rear-view camera system, the first offered in a GM vehicle.
Rear-view camera system: The available rear-view camera system can be ordered with the optional navigation radio system. The camera provides a view of the rear of the vehicle not easily seen, even with the outside or inside rearview mirrors, allowing the driver to check for persons or obstacles directly in the path of the vehicle. It also assists with parallel parking or trailer backing. Drivers should still inspect around their vehicles for objects or playing children.
A large, clear picture of the camera’s field of view is available on the navigation radio screen. The rear-view camera also works with the Ultrasonic Rear Parking Assist to provide an audible proximity reference to items in the camera’s view. If an rear parking assist sensor detects a person or object, it alerts the camera.
The camera only functions when the vehicle is shifted into Reverse. For convenience, it will stay on for a calibrated length of time – determined partly by vehicle speed – after the vehicle is shifted into Drive. The camera is mounted in the license plate surround bracket for an integrated styling appearance. It provides approximately 20 feet (6.1 meters) of viewing distance behind the vehicle.
OnStar Generation 6: All models come standard with the OnStar Generation 6system, including a one-year subscription to the Safe & Sound plan. The OnStar service includes the General Motors Advanced Automatic Crash Notification (AACN) system, making crash data available to emergency services to potentially dispatch the appropriate life-saving personnel and equipment to crash scenes faster. If the vehicle is in a crash that activates an airbag, the OnStar system automatically notifies an OnStar Advisor who will check on the occupants or summon emergency help if necessary. OnStar also can assist authorities in locating a vehicle if it is reported stolen and provides remote door-unlocking service
Remote starting system: A factory-installed remote vehicle starting system is available on most models – a first for GM’s full-size SUVs – providing customers with the convenience of starting the vehicle during inclement weather or other situations. The system has up to a 200-foot (61 meters) range and offers automatic climate pre-conditioning to warm or cool the vehicle prior to entry. On cold mornings, for example, the heat and defroster will be automatically turned on, even if the operator had last used the controls in a vent position.
The remote starting system is optional on some models and standard on others. Also, vehicles not originally equipped with the system are pre-wired at the factory so that the remote starting feature can be installed and activated by a GM dealership service department.
Tire pressure monitoring system: A revised and easier-to-use tire pressure monitoring system is standard on all models, providing drivers with peace of mind and contributing to a safer driving experience. The system alerts drivers via a signal on the instrument panel driver information center if a tire’s inflation status requires attention. In fact, the system sends a message to the information center each time the vehicle is started as part of a routine operations check. The driver also can use the information center to check the pressure of each tire. The pressure monitor sensors can detect air pressure differences to within one pound of the other tires.
Rain-sensing wipers: Available on some models is an optional rain-sensing windshield wiper system that automatically activates the wipers when precipitation is detected.
An infrared sensor located on the windshield (behind the inside rearview mirror) is used to detect raindrops. If rain or other precipitation is detected, the system signals the wipers to operate and adjusts wiper speed based on the intensity of the precipitation.
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