By BARRY LAKE
2 October 2006

The new Lexus RX400h is something of an enigma. It is a hybrid vehicle - that is, it employs a mix of petrol engine and electric motors and regenerates otherwise wasted power during braking and coasting. As such, it returns greatly improved fuel consumption figures over an equivalent vehicle powered by a normal internal combustion engine, and it pumps fewer pollutants into the atmosphere.

But if you seriously want to protect the environment, why would you be buying a big, heavy, luxury 4WD vehicle in the first place?

You could do a lot more good simply by buying a lighter, less powerful, yet equally roomy car with a conventional engine.

Obviously there are many people out there who don’t share these thoughts. Already 33,000 proud owners have purchased examples of this model and this represents 22 per cent of all Lexus RX (4WD) models sold in the US.

Lexus in Australia pre-sold the first three months supply of the vehicle and is expecting perhaps even more dramatic response than in the US, suggesting the RX400h could go to 20 per cent of all Lexus vehicles sold in this country.

After having driven the car, we have to say that Lexus has produced a very, very refined vehicle that is a pleasure to drive in city and suburban traffic. And this is where most examples will spend their lives. Very few, if any are likely to be seen scrambling up the steep, red sand of "Big Red", the largest of the 1100 sand dunes in the Simpson Desert.

Starting from standstill at moderate pace, the RX400h glides silently away, running on its electric motors. At higher speeds, it uses both the petrol engine and the front electric motor in varying ratios, depending on speed, load and other conditions.

The rear electric motor assists that at the front when starting from standstill, and then it cuts out as the vehicle gathers speed. Otherwise, it drives the rear wheels only when the front wheels lose traction. In that sense, it isn’t really a full all-wheel drive vehicle. Our test drive did not include any off-road driving, so we can’t comment on its potential in such conditions - and we suspect very few potential owners will be bothered by that omission.

The 3.3-litre petrol engine produces 155kW of power, the front electric motor has a maximum of 123 kW and the rear electric motor peaks at 50kW. At full throttle, full load, the vehicle can draw from both the engine and the electric motors to a maximum of 200kW.

Controlling the flow of power from engine and motors to the wheels is an electronically controlled continuously variable transmission.

Driving this car is not as boring as it sounds. Sure there is no gear shifting - either by driver or by ECU - but if you tramp on the accelerator pedal it really gets up and goes. And when ambling along at leisurely pace, you ride in eerily smooth and quiet comfort. The seats are excellent, everything is electrically adjustable, and interior styling is top class.

Lexus is selling the RX400h directly against the increasingly popular diesel-powered vehicles of its rivals. The company claims for this model lighter overall weight than its diesel rivals and better fuel consumption at what their maths calculations show as a lower price - specification for specification.

At $94,100 recommended retail price, the Lexus RX400h is loaded with standard features, many of which are extra-cost items in rival vehicles. Lexus claims a diesel powered direct rival might be advertised at $86,000 but would cost a massive $113,000 once it is optioned up to the levels of the Lexus.

Among the features are: 18-inch alloy wheels; anti-lock braking; stability control; traction control; airbags in front, side, knee and curtain positions; power-operated full leather seats; moon roof; a top class audio system with six-stacker CD player and 11 speakers; MP3 compatibility; adaptive front lights; rear spoiler; satellite navigation system; plus rear view camera with rear guide assist; and blue tooth compatibility - and a whole lot more.

This is a big, quality, sophisticated and luxurious vehicle that is listed as having average fuel consumption on the official tests of just 8.1 litres per 100 km.

Relative to many of its rivals it is a step in the general direction of environmental friendliness, and the marketing people say there are plenty of potential customers out there prepared to pay to create that impression among their peers. But our perception is that it simply is a way of justifying to one’s self having the biggest car on the block.