Just add driver

As proof that all technology is political, consider the 2006 Infiniti M45 Sport, bristling with electronic safety aids that, taken together, amount to the first stirrings of the automotive Nanny State.

Most notable is Lane Departure Warning (LDW). Debuting on the Infiniti FX45 crossover earlier this year, LDW uses a small camera on the back of the rearview mirror to track reflective lane markings and, crunching data from other sensors in the car, disciplines the driver with a reproving electronic tone (an “ear-con”) if it appears he or she is going astray. A virtual rumble strip.

LDW, available also on U.S. commercial vehicles, is a precursor to the automated lane-keeping technology that Japanese carmakers offer in their home market. While not quite hands-free commuting (not yet, anyway) these systems do help avert big shunts caused by inattention.

The new M45 is also equipped with Intelligent Cruise Control (ICC) -- now fairly commonplace in luxury cars -- that above certain speeds maintains a pre-set following distance with the help of radar or laser emitters in the car’s nose. When the car ahead slows down, you slow down. The next step in ICC tech is collision mitigation, which braces the car for impact and automatically applies the brakes if the driver should be asleep at the switch. Honda introduced such a system in Japan in 2003.

You see where this gets political or, more directly, cultural, don’t you? In the next decade, a host of smart vehicle technologies will be ready for prime time, including low-speed automation, in which the car essentially handles the drudgery of stop-and-go commuting; and “close-headway platooning,” in which cars -- acting either autonomously or in concert with the roadway’s controllers -- link up to create long trains of shiny personal boxcars. This technology could help relieve the hair-rending congestion of Los Angeles freeways, now overloaded and vapor-locked, and save oceans of fuel.

All that promise. But can Americans loosen their grip on the wheel without letting go altogether? When anti-lock brakes first came out, some consumers sued manufacturers when they discovered the technology did not, in fact, make their cars crash-proof. Even setting aside issues of liability and legislation, a fractious segment of auto enthusiasts will argue that these technologies -- which reduce driver “workload” -- only enable inattentive and incompetent driving.

Energizing these arguments is the soulful if dated idea that the driver should be in complete control, that with the privilege of a driver’s license comes an incumbency, a responsibility, a requirement of minimum skill. The car gives us freedom, not the other way around.

I’m not so sure. In my time with the LDW system, I didn’t resent the additional data. The system’s designers carefully chose the warning signal -- a gentle and courteous bell tone, not a buzzy rebuke -- to avoid alienating drivers. Also, there is a sly, behavioral quality to the system, subtly reinforcing signaling habits that even the best drivers can become complacent about. After a couple of days I found myself wanting to signal when I made a left turn for the kitchen.

And, by the way, you can turn the system off.

IT may seem a long way from the Infiniti M45 Sport. After all, with its active rear-steering, gluey 19-inch tires and 335 mousse-smooth horsepower, the M45 Sport feels less about safety than losing one’s license in a blood-bubbling fit of speed narcosis. No big Japanese

sedan has the right to handle half as well as this car. It just rips.

But technology is what this car is all about, that and style. In a market segment full of Armani-clad athletes such as the BMW 5-series and Lexus GS430, the M45 distinguishes itself with a world-class interior centered on a new, elegant dash control panel Infiniti calls -- with a touch of Asimov -- the Human Machine Interface.

Occupying a gentle swale in the central dash just below the LCD display panel, the control panel focuses on a rotary dial with compass-point buttons inside the bezel and flanking rows of buttons that look like frosted glass. High-use climate and audio controls are broken out above and below the main control panel for easy access.

In some editions of the M, gorgeous rosewood trim covers the dash and central console between the seats -- well, it looks gorgeous in pictures. I’m waiting at the end of my driveway for Infiniti to deliver a car so equipped.

The Sport edition I drove featured stippled aluminum, like the barrel of a Montblanc pen. The four-gauge instrument cluster employs a handsome “solar eclipse” design that surrounds the black-faced dials with a pumpkin-orange corona. Chrome bezels abound. This is one interior in which Infiniti’s signature oval clock doesn’t look randomly appended.

Compared with the plastic-crippled console in the previous M, this rich, premium-feeling dash is from an entirely different planet.

The M comes in five flavors: the base model M35 -- powered by Nissan/Infiniti’s stalwart 3.5-liter, 280-hp V6 motor -- comes in at $39,900. An all-wheel-drive version, using the same AWD system as the FX crossovers, is priced at $42,400; the Sport edition is slightly more still, $42,700.

The two M45 models (not available with AWD) motivate with a 4.5-liter, dual-overhead cam V8 sewing machine good for 335 hp and 340 pound-feet of torque, which is converted to seamless propulsion by the car’s five-speed automatic transmission.

You may find yourself tempted to use the manual-shift mode more than is typical with these types of transmissions. First, because the shifter knob, skinned in perforated leather, fits palm perfect; and second, because the transmission/engine control provides “rev-matching”: When when you downshift, the engine revs up to speed before the gear engages, so the transition doesn’t unbalance the car. Very nice.

Infiniti says it has “tightened” the torque converter for more affirmative throttle tip-in. So it would seem. The 2-ton car leaves the line already in mid-stride and picks up pace without a hint of strain. Zero to 60 mph goes by in about 5.6 seconds as the cabin fills with an increasingly lyric, ambient thrum. Once at cruising altitude, the car just glides.

Mat the throttle to pass, and the car kicks down two gears, blips the revs and shoots ahead, a recoilless rifle.

The M-ships are an evolution of Nissan’s FM (front-midship) platform, the same as under the G35 coupe and sedan. The car definitely feels stiffer and tighter than the G35 -- itself not exactly willowy. No doubt thanks to the 250 additional welds in the body construction, the M45 has a massive, cast-bronze feel to it. This deep structure provides the foundation for the car’s suspension (unequal-length control arms in front, multi-links in back, with anti-roll bars front and rear).

The ride is impeccable, silken over fine road hash and unflappable over whoops that can make cars fidgety in high-load cornering. The big 8.5-inch-wide performance tires hang on like a bad cold.

The sport editions of M-ships are also equipped with active rear steer, or active rear toe control, if you like. An electric actuator is situated between the rear lower control links. As you turn into the corner, the rear wheels angle slightly in the other direction -- like the back casters of a shopping cart -- helping the car attack the corner. Once in the corner, the wheels go in phase with the front wheels, helping the car corner harder and exit faster.

By the seat of my pants, I couldn’t really feel the rear-steer system engaging, but the M45 does seem possessed of some special cornering mojo. I want more.

THE only problem I see with Infiniti’s platform sharing is that it stamps the cars with a visual sameness. The M45 looks like a bigger G35 sedan with a stylist. As special as the M45’s technology is, I would have wrapped it in a more romantic and expressive package. As it is, the M45 has an expense-account look to it.

This is a car you can sink your Bluetooth into. Our test car had voice-recognition navigation with Nissan’s distinctive Birdview graphics; a rearview TV monitor that indicates the projected path of the car as it backs up; smart-key with push-button start; and a Bose surround sound system including four speakers situated in the front seat shoulders.

If $56,060 for a car ever seems like a deal, then it’s here.

If all that doesn’t give your covetous neighbors the shivers, there is an optional rear-cabin DVD entertainment system; power reclining, heated rear seats; rear sunshade; and rear climate controls. Don’t forget the rosewood.

This is an awesome car. Thanks to models like the FXs and the Gs, Infiniti has little rival for the title “most improved car brand.” The M45 Sport is the worthiest yet. It’s a car that makes you feel but also makes you think.

Automotive critic Dan Neil can be reached atdan.neil@latimes.com.

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(BEGIN TEXT OF INFOBOX)

Infiniti M45 Sport

Base price: $49,550

Price as tested: $56,060

Powertrain: 4.5-liter, dual-overhead cam, 32-valve V8, with variable-valve timing; five-speed automatic transmission with manual shift mode and downshift rev-matching; rear-wheel drive.

Horsepower: 335 at 6,400 rpm

Torque: 340 pound-feet at 4,000 rpm

Curb weight: 3,948 pounds

0 to 60 mph: 5.7 seconds

Wheelbase: 114.2 inches

Overall length: 192.6 inches

EPA fuel economy: 17 mpg city, 23 mpg highway

Final thoughts: Smarter than it looks