May 17, 2007

Feature: Toyota's Arizona Proving Grounds

By Paul Williams; photos by David Dewhurst

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Phoenix, Arizona - Built at a cost of $108,000,000 (U.S.) in 1993, the Toyota Arizona Proving Grounds (TAPG) facility has remained something of a mystery to journalists since opening day. It is, after all, in the middle of the desert, and surrounded by fences and security.


But things have changed. Wanting to show off the new all-wheel drive 2008 Lexus LS 600hL, and the state-of-the-art, 4,800 hectare TAPG facility (including a whopping 16-kilometre banked oval), Toyota opened the gates to the press a few weeks before launching the LS 600hL.

What's there? The oval (you can't miss that), and a 2.4-km ride/handling course, a 2.4-km dirt track, a 2.8-km brake test area, a 900-metre low friction test area and a 4,100-square-metre garage. Currently the TAPG track is the largest oval track in the world.

There was one condition when visiting: no cameras allowed. So, with thoughts of mischievously using the cameras in our cell phones, we dutifully handed in our gear at the gate before entering.

All Toyota and Lexus products sold in North America are tested at the TAPG, along with vehicles destined for world markets. The day's events enabled us to experience the LS 600hL with the latest Hybrid Drive System in each of the facility's main areas, and to sample the car's comprehensive handling, safety and convenience technologies.

The oval is rated for speeds up to 300 km/h, but we were unfortunately limited to 200 km/h (which in this car doesn't seem very fast at all). The point of lapping the oval was to demonstrate the vehicle's stability and responsiveness when lane-changing at speed and when braking and accelerating (it passed…).

The track also contains a rough pavement area that simulates road surfaces found in cities and on highways in the U.S. and Canada. While driving on these surfaces at 80 km/h, we could change ride and handling settings using the LS 600hL's standard Adaptive Variable Suspension (AVS) feature. Using this system, the driver can select sport, normal and comfort characteristics from a switch on the centre console. Switching between sport and comfort provided the greatest contrast, with the comfort setting all but eliminating a rough ride over broken or undulating pavement in some cases.

The AVS system can also raise the vehicle up to 25 mm for travelling over speed bumps or potholes.

Wet handling and rapid lane change manoeuvres were practiced at a skid pad where the car was aggressively driven through a slalom course. There, the Vehicle Stability Control (VSC) systems could be used or deactivated for comparison (both traction and VSC can be turned off). Interestingly, even without the electronic aids, the big Lexus is more manageable in slippery conditions than you might expect (which suggests it is an inherently well-balanced car). But on these challenging surfaces it can be a handful, and several drivers did lose control. When activated, the stability controls showed their worth by enabling the driver to drive through the course, at speed, virtually without incident.

Thus far, these were technologies we'd seen on other cars. What most of us hadn't experienced was the Advanced Pre-Collision System (APCS), available as part of the Executive Package. Using the full range of Lexus stability control technologies, plus a millimetre-wave radar system and stereo cameras, the APCS is designed to reduce crash speed and damage in the event of a frontal collision.

In practice, it can detect objects in the car's path, including people and animals, and supplement the driver's inputs to avoid them. Assuming evasive action is taken by the driver, the system coordinates with the car's braking, steering and suspension to optimize an evasive manoeuvre, and maximize the chances of avoiding an obstacle in its path.

In the event that evasive action is not taken (i.e. the driver steers straight into an object), the system will pre-tension the seatbelts and activate the brakes to rapidly decelerate the car so that it hits at a much-reduced speed. In our tests, the car slowed from 60 km/h to a 10 km/h speed at impact, without driver input.

The APCS system also monitors the position of the driver's face, and alerts the driver if distraction is detected for a prolonged period of time. The system calculates the direction of the face according to its width and position of the eyes and mouth. It then sends a face detection signal to the Pre-Collision ECU, which determines if there is a possibility of a collision and the driver is not facing forward. An audible, then visual signal is sounded, and the brakes pulsed.

The Ride and Handling component of the program used a specially designed road circuit to test the vehicle at speeds from 50-110 km/h. The track featured elevation changes and esses, along with sharp and decreasing radius corners (and the occasional wild animal). While Lexus engineers seemed particularly nervous about letting journalists onto this track, their worries were fortunately not warranted. Maybe the track would be more challenging in another vehicle, but the LS 600hL didn't really break a sweat.

A relaxed experience was testing the Lexus Self-Parking technology. Position the car properly, and it works perfectly. It was easy to use, I found, but it will be interesting to see how it works on a busy city street. However, for those who dread parallel parking, this is certainly a no-brainer. And for those about to take the test for your driver's licence… I don't think so.

From the perspectives of safety and vehicle control, the Lexus LS 600hL may be the most advanced luxury sedan on the market today. The company's chief engineer, Osamu Sadakata, is completely serious when he says he is working toward a car that cannot get into an accident (a stated goal from Toyota that has been consistent over the years). Doubtless we will see technologies of the type found on the LS 600hL trickle down to mainstream consumer vehicles as they become less expensive to produce.

In the meantime, a fortunate few (120 per year in Canada) will get to experience them now.