Toyota Prius v Mercedes Benz A-Class - Green or mean?

Fuel is not quite expensive enough yet for there to be wholesale change in the way we think about and buy our cars in New Zealand. Small cars as clean and innovative as these two are still only an occasional sight on our roads.

However, public pressure and increasing fuel costs could mean that such cars become more common. After a week driving Toyota's petrol-electric hybrid and Mercedes-Benz's A-class diesel head-to- head, I can't see as they'll prove much of a sacrifice.

The Prius is simply an electric car that carries around its own generator. By mating up an electric motor with a relatively small conventional petrol unit, the electric part of the system can fill-in where its petrol partner is weak, and vice- versa. Thus the car performs like a larger one without the fuel or environmental costs.

Other benefits are "free" charging from harnessing braking and engine energy and directing it back into the main batteries.

Driving as you would any car, with the air conditioning on, the lights ignited when needed, commuting to and from work and clocking some distance up at highway velocities, without pussy-footing – as is so-often the norm on competitive economy runs – I managed a reading of 5.2l/100km or 51.9mpg. That's not bad, making the car about 40 per cent more frugal than most others of its size.

TOYOTA PRIUS I-TECH

Drivetrain: Transverse mounted FWD fuel injected variable- valve timed 1497cc DOHC 16-valve petrol four producing 57kW at 5000rpm and 115Nm at 4000rpm, integrated with a permanent magnet synchronous AC electric motor producing 50kW at 1200-1540rpm and 400Nm at 0-1200rpm. Continuously variable transmission. Max speed 195kmh, 0-100kmh 11.3secs, average fuel consumption 5.2l/100km.

Chassis: Struts and coils at front, torsion beam at rear, stabiliser bars front and rear. Electronically controlled regenerative braking with vented front and solid rear discs, with ABS standard. Electrically power-assisted vehicle speed sensitive steering. 15 6JJ alloy wheels, 195/60R15 tyres.

Dimensions: L 4445mm, W 1725mm, H 1490mm, W/base 2700mm, F/track 1510mm, R/track 1480mm, Weight 1295kg, Fuel 45l.

Price: $43,500 to $50,000.

HOT: A simple drive; great refinement; subtly different styling; roomy cabin; a fuel sipper.

NOT: Chassis doesn't match drivetrain; sloping roof affects rear headroom; not quite brisk enough; too many functions dependent on centre screen.

OVERALL: It'll slow down fossil fuel consumption that's for sure, but you'll have to make compromises along the way.

BENZ A-CLASS

Drivetrain: Transverse mounted FWD 1699 and 2034cc petrol and 1991cc turbodiesel fours offering from 85kW to 103kW and 155Nm to 300Nm. Autotronic continuously variable transmission with sport and seven-step manual mode. Max speed 188kmh to 201kmh, 0-100kmh 9.5secs to 10.5secs, average fuel consumption 5.4l to 7.2l/100km.

Chassis: Struts and coils at front with anti-roll bar, parabolic rear axle with torsion bar. Vented front and solid rear discs, with ABS standard with EBD. Electrically assisted rack and pinion power steering. 15 or 16 x 6J rims with 185/65 R15 or 16 tyres, various alloy options available to 17-inch diameter.

Dimensions: L 3838mm, W 1838mm, H 1593mm, W/base 2568mm, F/track 1566mm, R/track 1551mm, Weight 1210-1345kg, Fuel 54l.

Price: $36,900 to $58,900.

HOT: Amazing space for size; disarmingly quick, especially diesels; decently frugal; engaging chassis; solid build; custom choices.

NOT: Single column stalk confuses; options add heavily to sticker price; wacky styling not for everyone.

OVERALL: Diesel can be almost as cheap to run as Prius, and better to drive and ride in, but can be expensive to buy.

There are some compromises. Ultimate interior packaging has to suffer so that the Prius can carry around its battery pack, but unlike the earlier models, the new car has a proper folding rear seat and a hatch. Rear legroom is excellent, though an ill-advised swoop of the stylist's pen has resulted in a dipping roofline that can annoy taller passengers. Top marks for frugality to the Prius but eight out of 10 for packaging.

Packaging is the A-class's forte. Despite the baby Benz being more than half a metre shorter than the Prius, its cabin is just as roomy and better in the back for headroom. Plus, it can be made to carry all sorts, through folding or removing any seats that aren't in use. The A-class uses body height to great advantage and if calculated around its diminutive 3838mm x 1838mm "footprint" it is probably the most efficient user of road space on the market.

It's pretty frugal too. Even in 1.7-litre petrol form, the A-class manages 6.8l/100km but running the A200D diesel model through the same loop as the Prius, I dipped down to 5.4l/100km or just on 50mpg, again with no recourse to switching off home comforts or lighting.

The diesel A-class owner has to pay a $31.41 per 1000km road-user charge, but even then the A200D would cost about $782 all up to run for 10,000km, with the Prius asking around a hundred dollars fewer than that. Each car is about $500 cheaper to run than equivalent conventional petrol models.

There will be arguments about the various merits of hybrids and diesel cars in terms of emissions. Europe has long decided that diesel is the way to go, having brought in a sliding scale of emissions yardsticks for them, while the United States has gone the way of the hybrid, having never been very strong in the area of diesel power for family cars.

In New Zealand the compunction to be clean and green – beyond our own consciences, that is – is absent, along with the Government's hopefully temporary abandonment of emissions testing, which means you can drive a worn-out smelly old dunger without feeling responsible for it.

So super-clean though the Prius is, apart from a small number of laudably keen, green citizens, the car suffers in the marketplace from there being no incentive to buy it, either by financial or tax relief or by dint of emissions law.

Diesel cars like the A200D also suffer in the market. At the mention of such fuel, the picture of smoky vehicles is brought to mind and the wee Benz is painted in many people's thoughts as just as dirty, slow and noisy.

It's none of these, and especially in A200D form, with 100kW on tap – not to mention 300Nm of torque; the A-class is an astonishingly brisk performer, scampering to 100kmh in well under 10 seconds. It does so driving through a CVT Autotronic transmission that can be operated manually with a selectable seven-step override facility.

The A200D is quite flexible enough being left to its own devices, displaying an urgency and liveliness that does rather set it apart from the Prius, which through its own CVT transmission gets to 100kmh in about 11 seconds or so. That's not especially slow, just a mark of one of the compromises required when driving the car.

There are few others. Low speed ride is a little harsh, but this improves at highway speed, while ultimate cornering grip is less than it could be thanks to low rolling resistance tyres.

The Benz's ride also suffers with optional sports tyres and suspension. I'd advise on standard wheels and tyres with which it can dispatch all manner of bumps with little trouble.

The A200D is a remarkably sharp handler and fun to drive, and its suspension contributes to a very calm cruising demeanour; road noise is well suppressed, as is wind flurry, making the baby Benz a pleasingly quiet drive.

But not as quiet or refined as the Prius, which settles back after the business of accelerating to speed to waft along almost limousine-like at 100kmh.

At low speeds it can be a little unnerving for cyclists as its engine switches off and leaves things to the electric motor, but you do get used to it, though pedestrians and cyclists can be surprised.

Well-equipped safety wise – as is the Prius, with front, side and curtain airbags in top models with the usual electronic chassis aids – the A-class adds to the equation by way of its double-floor construction. This sandwich adds to side impact protection and general body stiffness, and also gives the car's canted forward power unit somewhere to go in a head-on collision, sliding on impact between the two floors and dispersing energy away from the unaffected passenger capsule above.

Possibly the biggest difference between these cars apart from their exterior designs and drivetrains is in their driving environment.

The A200D's cabin is trimmed and designed in typical Mercedes-Benz fashion, belying the quirkiness of its exterior. Materials are good – with leather and wood as options, and assembly spot-on. The only criticism is the car's single column-stalk, which has to cope with being used for indicators, headlights, and wipers and washers, front and rear. It's a real fiddle.

For the Prius driver, a central screen is the conduit for all functions, from Sat-Nav, to stereo and radio, the air-conditioning and even a pictogram of the car's battery, engine and electric motor as they go about their power sharing. It's all a bit too much, and adds an extra step when adjusting normally single switch functions like station select, temperature choice or fan speed. Also fussy is the dash-mounted, cotton-reel sized "gear-button" that does the job of a conventional gear lever, and the card-in-the-slot and press button starts the car up.

But we're getting picky now, as these cars show that being sensible, frugal and indeed green – if we're made to – can be satisfying and fun.

The better cars in the next few years or so will be forced to take the best elements from each of these cars and put them together.

The Prius would definitely be better with the A-class's packaging and chassis, and the little Benz's double floor would even supply somewhere to put the battery pack.

The Toyota's synergy drive has a place for the future too, but it still depends on fossil fuel to do most of its work, however efficiently.

Perhaps an adaptation of a diesel engine could be coupled to the electric part of the Prius and made to run on home-grown rape seed and kale oil or the like – then there'd be no need for fossil fuels at all.

As they stand, I'd be proud to own either of them. The A200 offers least compromises in terms of driving the car day to day, to the extent that its more satisfactory performance is worth the extra $100 it would cost to run every 10,000km.

However, should the Government get serious about the Kyoto Protocol and slap some controls on emissions then my choice would be the Prius.

But I'd miss the engaging cheek and fun of the Mercedes.