YOUNTVILLE, CA – Ah, the Prius.

Has there ever been a vehicle that has so divided the motoring populace?

Critics castigate the world’s best-selling hybrid-electric vehicle for its mundane styling and handling and for obliterating the notion that driving can be fun and even exhilarating. How many Prius owners have ever driven a Mustang?

But to growing legions of HEV devotees who grip the steering wheel purely out of necessity, the Prius is Toyota Motor Corp.’s shining star, the gold standard for affordable, practical mobility and conservation. To these fans, the fuel-sipping Prius will save the auto industry and our planet, and they believe all other auto makers worldwide should emulate this hybrid.

Given its popularity with celebrities, suburbanites and auto “experts” in Washington, the onset of “Prius fatigue” is understandable.

But the all-new, third-generation Prius is hard to hate. During a test drive through Napa Valley, the new Prius lives up to the hype, which is sure to intensify in the months leading up to its late spring debut.

Easily topping 60 mpg (3.9 L/100 km) in varied drive routes and even reaching – brace yourself – 70 mpg (3.4 L/100 km) in the city, the ’10 Prius may put a serious crimp in sales of all other HEVs, plug-in HEVs, electric vehicles and fuel-cell vehicles in the pipeline.

The new Prius likely will carry a starting price close to that of the second-generation ’09 Prius ($22,000), or perhaps even lower, putting it more in reach for average Americans than pricier EVs, such as the $109,000 Tesla Roadster.

With the redesign, Toyota wisely keeps intact much of what is identifiable as “Prius,” most notably its egg-shaped profile and contented, smiling face.

However, the car’s front fascia is reworked slightly, with the Toyota logo moving down into the upper grille opening from its previous placement above the slit. The lower grille opening now is larger to lessen airflow resistance and boost cooling efficiency.

To improve aerodynamics and reduce drag, Toyota sharpened the Prius’ corners and moved the peak of the roof rearward and extended the rear spoiler. At the Detroit auto show in January, the auto maker proclaimed the new Prius would have the “world’s lowest” coefficient of drag, 0.25. Now, the claim has been scaled back to merely “one of the world’s lowest.”

Added length and width helps boost most interior dimensions, although 2.6 ins. (6.6 cm) of rear-seat legroom is sacrificed for cargo volume. To alleviate any backseat crunch, Toyota has thinned the front seatbacks.

The second row is neither claustrophobic nor particularly comfortable, but it is more spacious than that of its rival, the all-new Honda Insight.

The new Prius handles significantly better than the model it replaces. Driving the two back to back shows the new Prius to be more car, less golf cart.

The new, larger 1.8L 4-cyl. still strains but whines considerably less than the former 1.5L I-4.

Toyota says the Prius’ Hybrid Synergy Drive system is 90% new, and that the larger engine actually improves fuel economy by boosting torque from 82 lb.-ft. (111 Nm) in the old model to 105 lb.-ft. (142 Nm), allowing the new Prius to run on the highway at lower rpm.

Accessory belts have been eliminated to reduce friction, and the air-conditioning compressor and water pump are electrically driven.

Like the new Lexus RX 450h hybrid, the ’10 Prius benefits from a cooled exhaust gas recirculation system and exhaust heat recirculation system, both improving fuel efficiency.

’10 Toyota Prius
Vehicle type Front-engine, front-wheel-drive, 5-passenger, 4-door hatchback
Engine 1.8L DOHC 4-cyl. with aluminum head, block
Power (SAE net) 98 hp @ 5,200 rpm
Torque 4,000 rpm
Compression ratio 13.0:1
Electric motor 60 kW (80 hp) @ 13,500 rpm, 201.6V NimH battery
Transmission Continuously variable
Wheelbase 106.3 ins. (270 cm)
Overall length 175.6 ins. (446 cm)
Overall width 68.7 ins. (174 cm)
Overall height 58.7 ins. (149 cm)
Curb weight 3,042 lbs. (1,380 kg)
Base price TBD
EPA mpg 50/49 city/hwy (4.7-4.8 L/100 km)
Competition Ford Fusion/Mercury Milan Hybrid, Honda Civic Hybrid, Nissan Altima Hybrid, Toyota Camry Hybrid
Pros Cons
Mind-blowing mpg Cheap gas hurts sales
Nifty center stack Atari-esque graphics
Eco-plastics cool Leather isn’t

The car’s hybrid transaxle is 20% lighter, with a new planetary reduction gear and a gear-drive that replaces the outgoing transaxle’s chain drive.

Motor generator No.1 starts the engine, while motor generator No.2 drives the vehicle in electric mode. The second motor generator can operate at DC 650V maximum before conversion to AC, vs. the 500V maximum in the previous-generation model.

The nickel-metal-hydride battery mostly is carried over, but Toyota has made it more compact, improved cooling efficiency and reduced the number of fasteners.

During the test drive here, journalists are challenged to “beat the chief” by topping the fuel-economy achieved by Chief Engineer Akihiko Otsuka, who manages 62.9 mpg (3.7 L/100 km) on a 33.9-mile (55-km) route. The Napa Valley track meanders through neighborhoods and shopping districts, as well as 2-lane highways.

All the journalists surpass his number. Ward’s garners 70.3 mpg (3.3 L/100 km) with the AC and radio off and driving well below the speed limit at times. With light and steady acceleration during in-town cruising, posting that number isn’t difficult.

The winning team averages in the 75-mpg (3.1-L/100 km) range but admits to hogging the bike lane with the hazard lights on.

Driving purely on electric power proves elusive. Our braking is insufficient to charge the battery enough to be in EV mode more than a minute at a time. The gas engine kicks on every time speeds exceed 25 mph (40 km/h).

EV mode is one of three driver-selectable modes, and the most fuel-efficient. In Eco mode, the engine runs at peak efficiency. The throttle opening can be reduced up to 11.6% to save fuel in all driving situations.

In Power mode, throttle response is sharper for freeway merges, passing or hill climbs, with internal Toyota tests showing a 1.7-second improvement in acceleration time at half throttle from 30-50 mph (48-80 km/h).

The Prius now is on Toyota’s new, wider MC (midsize-car) platform. As a result, it feels much more rigid than the old Prius and resists body roll during aggressive cornering.

The new HEV retains a MacPherson strut front suspension and torsion beam rear setup. The front suspension caster angle is improved for better on-center steering performance, Toyota says.

The car’s rack-and-pinion electric power steering system is carried over but improved, with a new electric motor power-assist mounted on the steering column. The system has no belts, hoses, pump or power/steering fluid that need replacing.

Very light steering was a hallmark of the outgoing Prius. The new one is properly weighted, although at times it still feels slightly over-assisted.

The ’10 Prius gets disc brakes at all four wheels, eliminating the rear drums in the previous model. Aluminum calipers help reduce weight.

A noticeable improvement is the reduced start shock when the gas engine rumbles to life, accomplished by moving the engine mount, shortening the roll axis of the powertrain by 0.9 ins. (2.3 cm) and tweaking the hybrid system control logic to lessen vibration.

Despite plentiful hard plastics, the interior layout is handsome and functional, with an attractive “leaf vein” graining on the dash.

Controls are easier to reach on the protruding center stack, and the shifter is nicely placed, relocated from the steering column to the lower right of the driver.

The bulging center stack makes possible a Volvo-esque floor cubby to hold large objects, such as a purse. (Strangely, the button for the heated driver’s seat is placed inside the cubby, making it difficult to see.)

The new Prius is loaded with luxury-like equipment, including a high-end 8-speaker JBL audio system with navigation that includes Sirius XM Satellite Radio and Bluetooth hands-free phone and music capabilities. WMA and MP3 audio files are compatible. A rearview monitor is included.

The same voice-activated navigation system as in the new Lexus RX is available in the ’10 Prius, which enables more casual speaking commands.

Despite demands by current Prius owners for better-bolstered seats, the driver’s seat in our tester is flimsy. While not terribly comfortable, it has eco-friendly foam produced with 15% castor oil.

In addition, eco-plastic with 25% corn content is used in the inner and outer front and rear scuff plates, as well as the cowl side trim. Leather seating remains an option for Prius buyers, perhaps diminishing the car’s earth-friendly credentials due to the greenhouse gases generated by cattle ranching.

Cars will come from Toyota’s plant in Tsutsumi, Japan. The auto maker plans to sell 100,000 new units this year and 180,000 in 2010.

The starting price around $20,000 should shake up every auto maker readying an “alternative vehicle,” as Americans thus far have proven they like them inexpensive.

Honda Motor Co. Ltd. has said it intends to price its new entry-level HEV, debuting just weeks before the ’10 Prius, below $20,000.

The starting price for the ’09 Prius is about $22,000, but media reports from Japan suggest Toyota might push the all-new HEV below $20,000 to compete more directly with the Insight.

Even without the discount, the Prius is a good value that offers more space and better fuel economy, interior materials and features than the Insight.

Honda is right to force hybrid pricing downward to boost volumes. But Toyota already has done a good job on that front. The new Prius raises the bar for hybrids and should cement its reputation as the world’s most popular HEV.

cschweinsberg@wardsauto.com