Long post - quotes mostly
Good God, the speculating here is driving me crazy. There are these pesky things called facts out there, certainly we could better spend our time discussing those. Or, we could do insane things like driving around at 120 (Steve, seriously, check the pocket where you carry your common sense, I think it has a hole in it).
Here, look what Google found for me:
(Report of NHTSA investigator/engineer Bill Collins) Cause of crash - Very excessive speed- According to the 911 call made by the brother-in-law sitting in the back seat of the Lexus, the accelerator pedal was depressed in a full power condition and attempts by the driver to release the pedal were unsuccessful...
Other Significant Factors:
1. Accelerator Pedal - The pedal is made from a composite plastic that forms a rigid, one-piece lever. Beyond the main pivot, the lever is not hinged and has no means for relieving forces caused by interferences. Upon removing the pedal from the vehicle, the rotating motion of the pedal assembly was confirmed to be still operational. The return spring action was smooth and unencumbered.
2. Upon inspection of the crashed vehicle, it was found that an all-weather floor mate bearing the Lexus insignia was present in the driver's foot well vehicle with very minor fire damage. The mat was not secured by either of the two retaining clips. The right clip was installed into the grommet of the carpeting but not installed into the mat. The left clip was found under the middle of mat but not clipped to either the carpet or the rubber mat. Removal of the mat was difficult because the bottom edge of the accelerator pedal had melted to the upper right corner of the mat. Further inspection of the mat revealed that while it was a Lexus brand mat, it was not the correct application for the vehicle...When referenced, this part number [of the mat] indicates that it is used in a 2005-2009 Lexus RX400H sport utility vehicle.
3. Push Button Ignition Star with no Emergency Instantaneous Shut off device - In the event that this vehicle was producing unwanted power, there was no ignition key that could be mechanically actuated to instantaneously disconnect electric power to the engine. In place of the key is a software push button that delays the engine shutdown for three seconds once depressed. This instruction is not indicated on the dashboard.
4. The brake pads and calipers were inspected for heat generated by emergency braking. While there was significant fire damage to the majority of the vehicle, the pads, rotors, and calipers could still be observed. The left front wheel assembly and suspension were torn from the vehicle in the crash and had not been involved in the fire. Other rotors on the vehicle generally exhbibited similar conditions. Rotors were discolored and heated, had very rough surfaces, had substantial deposits of brake pad material, and showed signs of bright orange oxidation on the cooling fins consistent with endured braking. Pads were melted and rough with a considerable amount surface material dislocated to the leading edge. The friction surfaces were burned but somewhat reflective. The edges of the pads were bubbled. The calipers were also heat discolored with heat patterns in the area adjacent to the rotor.
The NHTSA investigator included photographs in his report, one of which (rear left caliper and rotor) is attached at the end of this post.
I'm not an engineer, but I am a trained and experienced accident investigator. I'm not a trained accident reconstruction expert, but I supervised their investigations so I've seen it done and reviewed the reports. And of course I'm way too damn good looking and too suave and debonair to be an engineer. I've looked at a lot of brakes and I've never seen anything that looks like the photograph. When I look at that photo a vision pops in my mind of Officer Saylor trying to put his foot through the floorboard as he jams down on the brake pedal for a very extended period of time.
Now, if you go look at the recall notice, it seems that Toyota is saying it's all just a problem with floor mats being improperly installed and secured:
Defect Summary: CERTAIN ALL WEATHER FLOOR MATS (AWFM) SPECIFICALLY SOLD AS AN OPTIONAL ACCESSORY ...THE AWFM INCLUDES TWO GROMMET HOLES AND RETAINING HOOKS (CLIPS) TO SECURE THE MAT TO THE VEHICLE'S CARPET. IF THE AWFM IS NOT SECURED BY ITSELF OR IF IT IS PLACED ON TOP OF AN EXISTING CARPETING FLOOR MAT, THE MAT COULD MOVE FORWARD DURING THE VEHICLE USAGE AND IT MAY INTERFERE WITH THE ACCELERATOR PEDAL.
Consequence Summary: THE ACCELERATOR PEDAL MAY TEMPORARILY BECOME STUCK IN A PARTIALLY DEPRESSED POSITION WHEN RETURNING TO THE IDLE POSITION. IF THIS CONDITION OCCURS, IT MAY INCREASE THE POSSIBILITY OF A CRASH.
But NHTSA is calling BS on the recall, saying that it ain't just the floor mats and that removing them is just a temporary fix:
NHTSA has told Toyota and consumers that removing the recalled floor mats is the most immediate way to address the safety risk and avoid the possibility of the accelerator becoming stuck. But it is simply an interim measure. This remedy does not correct the underlying defect in the vehicles involving the potential for entrapment of the accelerator by floor mats, which is related to accelerator and floor pan design.
Toyota immediately backpedaled and said it would cooperate with NHTSA to find answers.
The internets is full of other stories about Toyota products (and some other makes) doing the same thing. Earlier this year, NHTSA denied a request for a defect investigation on the Lexus ES350. Here is a very interesting read from the petition filed by the driver/owner:
Driving home from work, I experienced a sudden uncontrollable surge in acceleration causing my speed to increase from about 60 mph to 80+ mph. Immediately I began to brake hard as I was rapidly approaching traffic just ahead of me. Fortunately the inside left lane was unoccupied and I was able to make an immediate lane change. Initially I depressed the brake pedal as hard as I could using both feet but only managed to slow the vehicle to 40-45 mph. With my speed reduced, I alternated between pumping the accelerator pedal and pulling up on it from the underside with my right foot as it became clear that the throttle was stuck in an open position. The vehicle continued to speed back up to over 65 mph with less pressure on the brake pedal.
With traffic just ahead of me, I moved over to the left shoulder next to the center barrier and continued to try to release the open throttle. There were
clouds of smoke around the vehicle and the smell of burning materials from the overheating brakes. After finally getting the vehicle slowed down to about 25-30 mph, I shifted into “Neutral” and depressed the start/stop push button a number of times hoping to stop the engine but nothing happened. Instead the RPMs moved up into the redline range on the tachometer. I quickly shifted back into “Drive”; the vehicle jolted and rapidly accelerated to 60+ mph.
As the brakes were fading quickly, I was certain that I would need to shift back into “Neutral” and let the engine blow up to stop the vehicle. Suddenly the acceleration surge stopped and I was able to bring the vehicle to a stop about 1 ½ to 2 miles from where it had started. I quickly shifted into “Park” and depressed the start/stop push button to turn off the engine. The vehicle seemed to shutter as I did so. Upon restarting the car, I drove cautiously to Lexus of Wayzata a short distance away fully prepared to shift into “Neutral” if the acceleration repeated.
The car remains there over 5 weeks later.
Toyota responded by saying that the floor mats were at fault and no other problems were discovered. The owner stuck by his guns and involved NHTSA, and there was a lot of communication back and forth. In the end NHTSA said that there was no reason to believe it was anything other than the floor mats. Read the NHTSA denial of petition here:
http://pressroom.toyota.com/pr/tms/toyota/document/NHTSA_Filing.pdf
Cherry-picked are the following excerpts from the petition denial that I thought were interesting and germane:
ODI notes that the petitioner’s description of his attempts to “dislodge the throttle by alternatively pumping the accelerator pedal and pulling up on it from the underside” strongly suggest an accelerator pedal that is being physically “trapped” by some foreign object, such as the floor mat (in his case the original equipment carpet).
When ODI and VRTC investigators met with the petitioner and inspected his vehicle the accelerator pedal assembly was functioning properly and there were no anomalies noted in the return springs. Wear marks were noted at the leading edge of the front right edge of the carpet mat, which may have been an indication of contact between the mat and the bottom edge of the accelerator pedal. ODI confirmed that the pedal is such that it can be held down by the mat. Once trapped, the pedal can remain trapped after repeated efforts to “pump” the pedal.
And this one:
Many of the incident drivers interviewed by ODI have stated that application of the brakes reduced acceleration but did not stop the vehicle. In assessing these complaints ODI notes that brake effectiveness in controlling a stuck open throttle event is significantly reduced once the vacuum reserve of the vacuum boosted power assist system is depleted. The friction generated from brake application with the wheels driven by full engine power results in significant heating of the brake components. Continued operation in this mode causes degradation of the brake friction materials, further reducing brake effectiveness and the ability of the driver to control vehicle speed.
ODI notes that the petitioner confuses the Brake Assist system referenced in the Owner’s Manual with the brake power assist system. Brake Assist is a computer controlled automobile braking technology that increases braking pressure in an emergency situation (e.g., crash avoidance braking). The Brake Assist technology used by Toyota in the subject vehicles detects an emergency situation by monitoring the rate of change of brake hydraulic pressure from the master cylinder. Based on the information gathered by ODI in interviews of incident drivers, there is no reason to believe that Brake Assist was activated during the unwanted acceleration events. While virtually all of the drivers indicated that they applied a great deal of force to the brake pedal in an effort to slow and stop the vehicle, it is possible that the manner (i.e., rate) in which the force was applied, or the absence of the amplifying vacuum boost, did not produce a brake system pressure pulse that is necessary to activate the Brake Assist system.
And finally:
The engine can be turned off while in motion by pressing and holding the ignition push-button start/stop switch for at least three seconds. The press and hold function is meant to avoid inadvertent engine shut-off while in motion. Turning of the engine in this manner puts the vehicle electrical system in Accessory (“ACC”) mode, in which the steering wheel does not lock or retract (as opposed to putting the vehicle in “OFF” mode, which can only occur when the vehicle is in Park).
Petitioner cites the following language to support this claim: “The engine cannot be switched to OFF unless the shift lever is in P.” Toyota has indicated that this should be changed to the vehicle cannot be switched OFF until the shift lever is in Park.”
Petitioner references the following language: “When the engine switch is turned OFF, the steering wheel returns to its stowed position by moving up and away to enable easier driver entry and exit. Switching to ACC or IG-ON mode will return the steering wheel to the original position.”
In its May 14, 2009, letter, Toyota admits that in its description of the function of these features, even though “technically correct,” is confusing. Toyota states that it plans to revise this portion of the manual to address any confusion.
One does wonder why NHTSA was so staunchly on the "it's the mats, stupid" Toyota line just a few months ago, and now is making all different kinds of noises. Perhaps it's the result of new information, or maybe it's just a case of CYA after the death of four people.
One fact seems very clear.
Officer Saylor was applying the brakes with all the force he was capable of exerting. What seems reasonable to assume is that the brake assist systems (vacuum and computerized) were not doing their jobs. Without the assist systems the brakes weren't going to stop the car, and once brake components heated to the failure point, nothing was going to stop the car short of a crash.
