When I first started reviewing cars five years ago, I can assure you, I never thought I would find myself eagerly waiting to get behind the wheel of a Buick.

But that started to change when the redesigned LaCrosse arrived. And then came the midsize Regal, which combines sportiness and comfort. Put any badge you want on it, and it's simply a nice machine.

Then, when General Motors Co. rolled out the 2012 Buick LaCrosse with eAssist at the Los Angeles Auto Show last year, I couldn't wait. This isn't just a car, it's a movement. With so many pending regulations on fuel economy and whatnot coming down the road, the LaCrosse resembles what most future vehicles are going to look like.

The future is now — or at least this summer when the LaCrosse arrives at dealerships.

The idea is absolutely brilliant: Take all of the technology that makes cars more efficient and put them all together in the most reasonable way. Use things like electric power steering, engine start/stop, aggressive fuel shut-off, improved aerodynamics, low rolling resistance tires, and a small electric motor that boosts the car when it needs a little help to stretch a gallon of gas farther than anyone could have imagined.

About five years ago, GM had introduced a "mild hybrid" system on a few vehicles. The execution was miserable and the vehicles felt like they were built only so GM could tout a few vehicles with a hybrid badge. Green refrigerator magnets that said "Hybrid" would have been better.

To this day, GM still does not have a traditional two-mode gas-electric hybrid sedan. But eAssist makes me wonder if it needs one.

It is the exact opposite of those earlier mild hybrid. It works, makes the car extremely quiet and never uses the word "hybrid." The badge is not as important as the 25 mpg city and 37 mpg highway, which Buick estimates the LaCrosse will hit when EPA testing is done. The official numbers will be released in the coming weeks.

For comparison sake, other large sedans don't even come close to the LaCrosse's mileage. If people pull them up in comparison charts like the handy dandy one on Kelley Blue Book (kbb.com), they will think the 2012 LaCrosse numbers are a typo. The subcompact Honda Fit gets 35 mpg highway. The midsize 2011 Toyota Camry hits 32 mpg highway. Even the previous four-cylinder LaCrosse got only 31 mpg highway.

Furthermore, the Buick LaCrosse with eAssist is not some limited-edition super-fuel-economy model that only a few people will see or drive. It's the base model flagship for a premium brand. It has all of the trappings you'd expect in a car of this class and caliber. All of the gizmos and gadgets are there. It has those big comfortable seats and more leg room in the front and back than a theater seat. It's comfortable and complete. There are even a few eco-friendly gauges to help the driver take a little lead out of his foot and leave a little more gold in his pocket. It's an alchemist's dream.

System stays in background

While I only got to drive the 2012 LaCrosse for a little over an hour, I was impressed at how utterly unimpressive the eAssist was.

Everything works in the background. There's no electric motor whirl at takeoff. There's no pull of the re-gen motor when the brakes are applied. There is only the slightest of vibrations, hardly noticeable when the engine restarts after pausing at a stoplight.

The system works so smoothly few will notice. When the LaCrosse eAssist arrives, there will be customers who never realize exactly how gasoline frugal their car is or that this car is acting like a hybrid in many ways — and in some ways, more sophisticated than a traditional hybrid.

See, what really smart engineers have done is connect a 15-horsepower electric motor to the engine to assist it whenever there's a need. The electric assist (eAssist. Get it?) will add some power at different moments. Whether pushing up a slight grade of road or starting the LaCrosse from a standstill, the electric motor can keep the car in a higher gear longer, or just help move it without using any additional fuel. The motor is not strong enough to drive the car through a parking lot like most hybrids today, but it doesn't need to — it actually provides better mileage than a number of gas-electric hybrids on the road today.

It also uses the motor as a generator to collect energy when the LaCrosse is coasting or slowing down. By now, most people understand regenerative braking, which turns energy once lost as heat on the brake pads into electricity that is sent to a small lithium-ion battery pack in the truck. That energy is then later used to seamlessly assist the engine.

Sum greater than pieces

This LaCrosse just glided through the hills and country roads around Milford — home to GM's proving grounds — where I test drove it.

There were a few times, if you really stepped on the gas, that the engine whined a little bit, a product of GM's 2.4-liter four-cylinder engine needing just a bit more power than its 182 horses available. But those were the extreme conditions — for the most part it just kept chugging along. On the highway, the LaCrosse felt at home around 80 mph. (It's unlikely it will get 37 mpg at that speed, but I was just keeping up with traffic.)

The steering feels crisp and firm and the suspension falls to the soft-but-firm side of a ride. But, again, there's nothing wrong with that in this car, which is by no means a race car. If gas is at $4 a gallon, you could drive this car to Chicago for around $32, which is still a couple of billion dollars cheaper than a high-speed rail ticket. And the LaCrosse could get you there in five hours — the super-train will take five decades.

The ride is likely quieter, too. Engineers improved its aerodynamics by adding a number of panels under the body. Cutting wind resistance also cuts noise.

That's the funny thing about this Buick. I asked if engineers could break down point by point how each improvement increases fuel economy. Does the EPA's improve things 6 percent, the electric motor 12 percent and the aero 4 percent? But, really, it doesn't work that way.

If the air resistance is lower, the engine doesn't stress as much, so the battery can hold its charge longer and the electric motor can kick in a little less from time to time. But the electric steering draws power from the batteries but also eliminates parasitic engine losses at the same time. Each improvement impacts a number of areas, which in turn can pay it forward at the pump.

The sum of the 2012 LaCrosse is truly greater than its pieces.

sburgess@detnews.com (313) 223-3217