INTRODUCTION
The Acura MDX SUV is engineered to meet and often exceed all applicable safety standards. Safety, security, and accident avoidance are main Acura priorities. With that in mind, various systems - body structure, chassis, driveline, passenger restraints - interact positively to help the driver steer clear of hazards whenever possible and enhance occupant protection in the event an accident is unavoidable.
The Variable Torque Management (VTM-4) all-wheel-drive system is the key to sure-footed handling and straightforward controllability whether the pavement is dry or wet and slippery. Combined with MDX's Vehicle Stability Assist (VSA), 4-wheel independent suspension, torque sensing power rack-and-pinion steering, and four-wheel-disc brakes with ABS, VTM-4 delivers best-in-class traction to enhance the driver's ability to guide an MDX safely out of harm's way.
To help safeguard occupants from injury when a collision is unavoidable, MDX provides multiple layers of protection. The computer-engineered body structure features front, side and rear crumple zones to help protect occupants during offset and side impacts, and a well protected fuel tank. Extensive use of high-strength steel yields a robust safety cage surrounding passengers without incurring an awkwardly heavy curb weight.
All seating positions have three-point seat belts. Front seat belts are equipped with pretensioners and automatic load limiters that are activated in certain collision conditions. The MDX comes with standard front dual stage, dual threshold front airbags. These airbags can deploy at the most appropriate of two rates depending on the severity of the crash. In addition, if the driver's or passenger's seat belt is not fastened, the air bag deploys at a lower collision speed to help offer more protection to the unbelted occupant. Additionally, the MDX features two weight sensors in the front passenger's seat and a driver's seat position sensor as part of the dual-stage, dual-threshold front airbag system.
The driver's and front passenger's seats also feature side airbags mounted in the seat bolster closest to the door. The passenger's seat is equipped with a system of sensors designed to disable side air bag deployment and prevent injury to a small child (or small-statured adult) if they lean into the side air bag deployment path. Once the child returns to an upright seating position, the side air bag will reactivate so it can deploy and protect the child in a side impact.
Helping protect all three rows of occupants in all 2004 MDXs is the new roof-mounted Side Curtain Airbag system with side impact and roll-over sensors. In addition to the side impact protection, this new system can activate in the unlikely event of a rollover. Depending on the speed of the vehicle and the rate of roll detected by the sensors, the side curtain airbags deploy at different speeds to best protect outboard occupants in the event of a rollover - faster for a sharp roll rate such as encountering a steep embankment, slower in the case of losing balance after hitting a curb or like structure.
In internal frontal and side impact crash tests conducted according to guidelines used by the National Highway Traffic Safety Administration (NHTSA) and the Insurance Institute for Highway Safety (IIHS), the 2004 MDX achieved 5-star ratings.
SAFETY STRUCTURE
MDX engineers used powerful computers to assure that this vehicle's safety cage structural design would perform well even before physical prototypes were built. Crash simulations helped reveal areas of the design that needed more - and sometimes less - reinforcement to absorb energy while resisting intrusion.
MDX has an especially robust floor construction to optimize both rigidity and resiliency. Two longitudinal rails run continuously from bumper to bumper. The rails are buttressed by a total of eight box-section crossmembers and two bumper bulkheads. This provides the strength needed to resist standard barrier impacts at the front and rear, offset crashes (wherein most of the load is applied longitudinally to one corner of the vehicle), and side impacts.
A four-ring shell-type safety cage is used to help protect occupants with A, B, C, and D pillars that run continuously to avoid intrusion during side impacts. To meet current federal head-impact requirements, roof-pillar trim and headliner materials absorb energy and help reduce the likelihood of occupant head injury. Stiffeners inside the doors at the beltline provide a continuous horizontal connection between the first three pillars. Tubular beams are welded inside the doors at wheel height to provide additional intrusion resistance.
One quarter of the body structure - longitudinal rails, floor crossmembers, pillar reinforcements, and bumper beams - is made of high-tensile steel for maximum strength with minimal weight.
MDX's fuel tank is made of highly puncture-resistant, six-layer, high-density molded-polyethylene, with high-strength, box-section floor reinforcements to help guard it from side collision damage. It is located ahead of the rear axle for protection.
FRONTAL RESTRAINT SYSTEMS
Unlike some SUVs, MDX provides a three-point restraint system for all seven seating positions. A special roof-mounted reinforcement, positioned between the C and D pillars, serves as a rigid mounting point for the second row, middle passenger's shoulder belt.
Front seat belts are equipped with pretensioners and automatic load limiters that are activated in conjunction with the front airbags.
DUAL-STAGE, DUAL-THRESHOLD FRONT AIRBAGS
The MDX is equipped with dual-stage, dual-threshold airbags for the driver and front passenger. These airbags are designed to minimize the potential for airbag injury while providing head and chest protection for the occupants in the event of a collision. This front airbag system features additional sensors; front passenger seat weight sensors, and a driver seat position sensor designed to enhance occupant protection.
The MDX's front airbags can deploy at one of two rates. Deployment of the driver's side airbag takes into account the severity of the crash, whether or not the driver's seat belt is fastened and the position of the driver's seat. During a lower speed collision, the airbag inflators are triggered in sequence, resulting in slower overall airbag deployment with less initial force. The same sequence is also utilized regardless of collision speed if the driver's seat is within a half inch of the full forward position. During a higher speed collision, if the driver's seat is more than a half inch from the full frontal position, both inflators operate simultaneously for full, immediate inflation. Airbag deployment on the front passenger's side is regulated by crash severity, seatbelt usage as well as the weight of the occupant. Sensors under the seat gauge occupant weight and if the total weight on the passenger seat is less than 65 lbs, the airbag system will not deploy, minimizing the potential for injury to children. Just as the driver's side, the airbags are deployed at the speed appropriate to the speed and severity of the collision - slower for lower speed collisions, more quickly for higher speeds.
The driver's airbag is located in the steering wheel hub and the passenger's airbag is located on top of the dash. As in all Acura vehicles, the front passenger's airbag is designed to deploy upward toward the windshield and then back toward the occupant. This provides a large cushion to help protect the front passenger.
SIDE AIRBAG SYSTEM
Like other Acura models, MDX is equipped with seat-mounted side airbags to help safeguard the driver and front passenger from side-impact injury. An innovative occupant position detection system is used to assure that the passenger's side airbag has a clear path for deployment. In the event a child (or a small-statured adult) leans into the deployment path of the side airbag, a seven-segment antenna system built within the backrest signals this condition to an electronic control unit (ECU) also located within the seat. The ECU then deactivates the side air bag from functioning and triggers a "SIDE AIRBAG OFF" indicator light in the instrument cluster. After the front occupant returns to a normal seating position, the side air bag module automatically resumes full-functional status.
SIDE CURTAIN AIRBAG SYSTEM
For 2004, all three rows of occupants are protected by Acura's new roof-mounted Side Curtain Airbag System, which is standard equipment on all MDX models. The side curtain airbags deploy from a module in the roof in the event of a sufficient side impact, providing an important and significant level of head protection in the window area. In the unlikely event of a rollover, a roll angle sensor along with lateral G and transverse G sensors, located just in front of the windshield base determine the rate of roll and deploy the side curtain airbags accordingly.
Like the other airbag systems in the MDX, the side curtain system utilizes sensors located in the front of the vehicle to determine the most appropriate timing and rate of deployment of the airbags in the event of a rollover.
To provide the optimal level of protection for MDX occupants, extensive testing was performed to determine the most appropriate timing and rate of deployment in the unlikely event of a rollover. The system uses algorithms to continually evaluate the situation and determines whether a rollover is eminent. The system responds to the three types of rollover "scenarios" drivers would potentially encounter: the "curb trip rollover" which as its name suggests, results when one side of the vehicle hits a curb or like object; the "soil trip rollover" which can result when one side of the vehicles suddenly comes into contact with a different surface type, often involving a slight elevation change; and finally, the "screw rollover." This type of rollover is usually the steepest and fastest of the rollovers whereby the vehicle comes upon a sharp angle such as an embankment. The gyro roll and lateral G-roll sensors determine the "scenario" and calculate the rate of roll and the speed of the vehicle in order to deploy the airbags at the correct stage for optimum protection. Similar to the dual-stage, dual-threshold front airbags, the side curtain airbags will deploy at the faster or "full" rate in the case of a screw rollover and more slowly in a curb trip rollover. In the case of a rollover, the side curtain airbags on both sides of the vehicle will deploy. However, in the event of a sufficient side impact that does not result in a rollover, only the airbags on the impacted side of the vehicle will deploy.
TIRE PRESSURE MONITORING SYSTEM
The 2004 MDX has been equipped with an all-new direct Tire Pressure Monitoring System (TPMS). Using a series of four sensors and four initiators (one for each tire) and a receiver to capture and relay information, the system alerts the driver when it detects that tire pressure in one or more tires drops significantly below the recommended pressure.
The sensor transmitter is located inside the wheel. Should the tires be rotated around the vehicle due to normal maintenance or be replaced entirely, the new tires are "auto-located" by the system. If the system detects that tire pressure is significantly low (32 psi is recommended), the low tire pressure indicator located in the meter containing the fuel level and temperature gauge will come on while a schematic of the vehicle located in the center meter housing the speedometer will indicate which tire or tires is low.
ANTI-THEFT ALARM SYSTEM
MDX has a standard keyless-remote entry system that locks and unlocks all doors and the rear hatch at the push of a button. To enhance theft protection, only one key lock mechanism is provided for the driver's door position. The same key fob used to lock the doors also activates the MDX's security system. In response to any attempt to enter the vehicle without the key fob or ignition key, the horn sounds, and the flasher lamps are activated. If need be, the alarm system can be triggered to summon help by depressing a "panic" button on the remote-keyless fob.
SECURITY/IMMOBILIZER SYSTEM
Imbedded within MDX's ignition key is an electronic microprocessor circuit that communicates with a receiver in the ignition switch to enable the vehicle's electrical systems. Forcibly vandalizing the ignition switch, hot-wiring, or attempting to start the car with a key lacking the microprocessor circuit will result in immobilization. Without proper key-to-immobilizer communication, the MDX will simply not start.
LOWER ANCHORS AND TETHERS FOR CHILDREN (LATCH) SYSTEM
The Lower Anchors and Tethers for Children (LATCH) system is standard on the second row of outboard seats. The LATCH system features built-in, ready-to-use anchors and tethers allowing compatible child safety seats to be installed without using the vehicle's seat belt system.